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	Author	Ke, X.
	Title	From top-down to bottom-up : from carbon nanotubes to nanodevices			Type	Doctoral thesis
	Year	2010	Publication		Abbreviated Journal
	Volume		Issue		Pages
	Keywords	Doctoral thesis; Electron microscopy for materials research (EMAT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Antwerpen	Editor
	Language		Wos		Publication Date	0000-00-00
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ lucian @ c:irua:87408			Serial	1289
Permanent link to this record



	Author	Zhou, X.-G.; Yang, C.-Q.; Sang, X.; Li, W.; Wang, L.; Yin, Z.-W.; Han, J.-R.; Li, Y.; Ke, X.; Hu, Z.-Y.; Cheng, Y.-B.; Van Tendeloo, G.
	Title	Probing the electron beam-induced structural evolution of halide perovskite thin films by scanning transmission electron microscopy			Type	A1 Journal article
	Year	2021	Publication	Journal Of Physical Chemistry C	Abbreviated Journal	J Phys Chem C
	Volume	125	Issue	19	Pages	10786-10794
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	A deep understanding of the fine structure at the atomic scale of halide perovskite materials has been limited by their sensitivity to the electron beam that is widely used for structural characterization. The sensitivity of a gamma-CsPbIBr2 perovskite thin film under electron beam irradiation is revealed by scanning transmission electron microscopy (STEM) through a universal large-range electron dose measurement, which is based on discrete single-electron events in the STEM mode. Our research indicates that the gamma-CsPbIBr2 thin film undergoes structural changes with increasing electron overall dose (e(-).A(-2)) rather than dose rate (e(-).A(-2).s(-1)), which suggests that overall dose is the key operative parameter. The electron beam-induced structural evolution of gamma-CsPbIBr2 is monitored by fine control of the electron beam dose, together with the analysis of high-resolution (S)TEM, diffraction, and energy-dispersive X-ray spectroscopy. Our results show that the gamma-CsPbIBr2 phase first forms an intermediate phase [e.g., CsPb(1-x)(IBr)((3-y))] with a superstructure of ordered vacancies in the pristine unit cell, while a fraction of Pb2+ is reduced to Pb-0. As the electron dose increases, Pb nanoparticles precipitate, while the remaining framework forms the Cs2IBr phase, accompanied by some amorphization. This work provides guidelines to minimize electron beam irradiation artifacts for atomic-resolution imaging on CsPbIBr2 thin films.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000655640900061	Publication Date	2021-05-11
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1932-7447; 1932-7455	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	4.536	Times cited		Open Access	Not_Open_Access
	Notes				Approved	Most recent IF: 4.536
	Call Number	UA @ admin @ c:irua:179187			Serial	6880
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	Author	Corthals, S.; van Noyen, J.; Liang, D.; Ke, X.; Van Tendeloo, G.; Jacobs, P.; Sels, B.
	Title	A cyclic catalyst pretreatment in CO₂ for high yield production of Carbon nanofibers with narrow diameter distribution			Type	A1 Journal article
	Year	2011	Publication	Catalysis letters	Abbreviated Journal	Catal Lett
	Volume	141	Issue	11	Pages	1621-1624
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	This paper presents a cyclic catalyst pretreatment process to improve the CNF yield with narrow size distribution by sequentially feeding the CVD reactor with CH4/CO2 mixtures (carbon deposition) and CO2 (carbon removal) prior to the actual growth process. A mechanism based on a break-up of large Ni particles tentatively explains the beneficial effect of the cyclic carbon deposition/removal CVD procedure.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Basel	Editor
	Language		Wos	000296471400006	Publication Date	2011-09-26
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1011-372X;1572-879X;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.799	Times cited	1	Open Access
	Notes	Iwt; Iap			Approved	Most recent IF: 2.799; 2011 IF: 2.242
	Call Number	UA @ lucian @ c:irua:91888			Serial	598
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	Author	Guttmann, P.; Bittencourt, C.; Ke, X.; Van Tendeloo, G.; Umek, P.; Arcon, D.; Ewels, C.P.; Rehbein, S.; Heim, S.; Schneider, G.
	Title	TXM-NEXAFS of TiO₂-based nanostructures			Type	P1 Proceeding
	Year	2011	Publication	AIP conference proceedings	Abbreviated Journal
	Volume	1365	Issue		Pages	437-440
	Keywords	P1 Proceeding; Electron microscopy for materials research (EMAT)
	Abstract	In this work, electronic properties of individual TiOx-pristine nanoribbons (NR) prepared by hydrothermal treatment of anatase TiO(2) micro-particles were studied using the HZB transmission x-ray microscope (TXM) at the BESSY II undulator beamline U41-FSGM. NEXAFS is ideally suited to study TiO(2)-based materials because both the O K-edge and Ti L-edge features are very sensitive to the local bonding environment, providing diagnostic information about the crystal structures and oxidation states of various forms of titanium oxides and sub-oxides. TXM-NEXAFS combines full-field x-ray microscopy with spectroscopy, allowing the study of the electronic structure of individual nanostructures with spatial resolution better than 25 nm and a spectral resolution of up to E/Delta E = 10000. The typical image field in TXM-NEXAFS measurements is about 10 mu m. 10 mu m, which is large compared to the individual nanoparticle. Therefore, one image stack already contains statistically significant data. In addition, the directional electric field vector ((E) over bar) of the x-rays can be used as a “search tool” for the direction of chemical bonds of the atom selected by its absorption edge.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	New York	Editor
	Language		Wos	000298672400103	Publication Date	2011-09-19
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor		Times cited	2	Open Access
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ lucian @ c:irua:113071			Serial	3789
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	Author	Tsoufis, T.; Georgakilas, V.; Ke, X.; Van Tendeloo, G.; Rudolf, P.; Gournis, D.
	Title	Incorporation of pure fullerene into organoclays : towards C₆₀-pillared clay structures			Type	A1 Journal article
	Year	2013	Publication	Chemistry: a European journal	Abbreviated Journal	Chem-Eur J
	Volume	19	Issue	24	Pages	7937-7943
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	In this work, we demonstrate the successful incorporation of pure fullerene from solution into two-dimensional layered aluminosilicate minerals. Pure fullerenes are insoluble in water and neutral in terms of charge, hence they cannot be introduced into the clay galleries by ion exchange or intercalation from water solution. To overcome this bottleneck, we organically modified the clay with quaternary amines by using well-established reactions in clay science in order to expand the interlayer space and render the galleries organophilic. During the reaction with the fullerene solution, the organic solvent could enter into the clay galleries, thus transferring along the fullerene molecules. Furthermore, we demonstrate that the surfactant molecules, can be selectively removed by either simple ion-exchange reaction (e.g., interaction with Al(NO3)3 solution to replace the surfactant molecules with Al3+ ions) or thermal treatment (heating at 350 °C) to obtain novel fullerene-pillared clay structures exhibiting enhanced surface area. The synthesized hybrid materials were characterized in detail by a combination of experimental techniques including powder X-ray diffraction, transmission electron microscopy, X-ray photoemission, and UV/Vis spectroscopy as well as thermal analysis and nitrogen adsorptiondesorption measurements. The reported fullerene-pillared clay structures constitute a new hybrid system with very promising potential for the use in areas such as gas storage and/or gas separation due to their high surface area.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Weinheim	Editor
	Language		Wos	000319825500035	Publication Date	2013-04-15
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0947-6539;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	5.317	Times cited	3	Open Access
	Notes	262348 Esmi; 246791 Countatoms			Approved	Most recent IF: 5.317; 2013 IF: 5.696
	Call Number	UA @ lucian @ c:irua:107347			Serial	1599
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	Author	Chen, J.-J.; Ke, X.; Van Tendeloo, G.; Meng, J.; Zhou, Y.-B.; Liao, Z.-M.; Yu, D.-P.
	Title	Magnetotransport across the metal-graphene hybrid interface and its modulation by gate voltage			Type	A1 Journal article
	Year	2015	Publication	Nanoscale	Abbreviated Journal	Nanoscale
	Volume	7	Issue	7	Pages	5516-5524
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	The graphene-metal contact is very important for optimizing the performance of graphene based electronic devices. However, it is difficult to probe the properties of the graphene/metal interface directly via transport measurements in traditional graphene lateral devices, because the dominated transport channel is graphene, not the interface. Here, we employ the Au/graphene/Au vertical and lateral hybrid structure to unveil the metal-graphene interface properties, where the transport is dominated by the charge carriers across the interface. The magnetoresistance (MR) of Au/monolayer graphene/Au and Au/stacked two-layered graphene/Au devices is measured and modulated by gate voltage, demonstrating that the interface is a device. The gate-tunable MR is identified from the graphene lying on the SiO2 substrate and underneath the top metal electrode. Our unique structures couple the in-plane and out-of-plane transport and display linear MR with small amplitude oscillations at low temperatures. Under a magnetic field, the electronic coupling between the graphene edge states and the electrode leads to the appearance of quantum oscillations. Our results not only provide a new pathway to explore the intrinsic transport mechanism at the graphene/metal interface but also open up new vistas of magnetoelectronics.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Cambridge	Editor
	Language		Wos	000351372400050	Publication Date	2015-02-19
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2040-3364;2040-3372;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	7.367	Times cited	3	Open Access
	Notes	246791 Countatoms			Approved	Most recent IF: 7.367; 2015 IF: 7.394
	Call Number	c:irua:125533			Serial	1931
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	Author	Bittencourt, C.; Ke, X.; Van Tendeloo, G.; Tagmatarchis, N.; Guttmann, P.
	Title	NEXAFS spectromicroscopy of suspended carbon nanohorns			Type	A1 Journal article
	Year	2013	Publication	Chemical physics letters	Abbreviated Journal	Chem Phys Lett
	Volume	587	Issue		Pages	85-87
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	We demonstrate that near-edge X-ray-absorption fine-structure spectroscopy combined with full-field transmission X-ray microscopy can be used to study the electronic structure of suspended carbon nanohorns. Based on reports of electronic structure calculations additional spectral features observed in the π region of the NEXAFS spectrum recorded on the carbon nanohorns were associated to the presence of the pentagonal rings and the folding of the graphene sheet.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Amsterdam	Editor
	Language		Wos	000326104500016	Publication Date	2013-09-18
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0009-2614;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	1.815	Times cited	4	Open Access
	Notes	Fp7; Countatoms;			Approved	Most recent IF: 1.815; 2013 IF: 1.991
	Call Number	UA @ lucian @ c:irua:111592			Serial	2339
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	Author	Hoek, M.; Coneri, F.; Poccia, N.; Renshaw Wang, X.; Ke, X.; Van Tendeloo, G.; Hilgenkamp, H.
	Title	Strain accommodation through facet matching in La_1.85Sr_0.15CuO₄/Nd_1.85Ce_0.15CuO₄ ramp-edge junctions			Type	A1 Journal article
	Year	2015	Publication	APL materials	Abbreviated Journal	Apl Mater
	Volume	3	Issue	3	Pages	086101
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	Scanning nano-focused X-ray diffraction and high-angle annular dark-field scanning transmission electron microscopy are used to investigate the crystal structure of ramp-edge junctions between superconducting electron-doped Nd1.85Ce0.15CuO4 and superconducting hole-doped La1.85Sr0.15CuO4 thin films, the latter being the top layer. On the ramp, a new growth mode of La1.85Sr0.15CuO4 with a 3.3° tilt of the c-axis is found. We explain the tilt by developing a strain accommodation model that relies on facet matching, dictated by the ramp angle, indicating that a coherent domain boundary is formed at the interface. The possible implications of this growth mode for the creation of artificial domains in morphotropic materials are discussed.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000360656800009	Publication Date	2015-08-03
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2166-532X;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	4.335	Times cited	4	Open Access
	Notes	312483 Esteem2; 246791 Countatoms; esteem2_jra2			Approved	Most recent IF: 4.335; 2015 IF: NA
	Call Number	c:irua:127690 c:irua:127690			Serial	3163
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	Author	Shan, L.; Punniyakoti, S.; Van Bael, M.J.; Temst, K.; Van Bael, M.K.; Ke, X.; Bals, S.; Van Tendeloo, G.; D'Olieslaeger, M.; Wagner, P.; Haenen, K.; Boyen, H.G.;
	Title	Homopolymers as nanocarriers for the loading of block copolymer micelles with metal salts : a facile way to large-scale ordered arrays of transition-metal nanoparticles			Type	A1 Journal article
	Year	2014	Publication	Journal of materials chemistry C : materials for optical and electronic devices	Abbreviated Journal	J Mater Chem C
	Volume	2	Issue	4	Pages	701-707
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	A new and facile approach is presented for generating quasi-regular patterns of transition metal-based nanoparticles on flat substrates exploiting polystyrene-block-poly2vinyl pyridine (PS-b-P2VP) micelles as intermediate templates. Direct loading of such micellar nanoreactors by polar transition metal salts in solution usually results in nanoparticle ensembles exhibiting only short range order accompanied by broad distributions of particle size and inter-particle distance. Here, we demonstrate that the use of P2VP homopolymers of appropriate length as molecular carriers to transport precursor salts into the micellar cores can significantly increase the degree of lateral order within the final nanoparticle arrays combined with a decrease in spreading in particle size. Thus, a significantly extended range of materials is now available which can be exploited to study fundamental properties at the transition from clusters to solids by means of well-organized, well-separated, size-selected metal and metal oxide nanostructures.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000329069900015	Publication Date	2013-11-12
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2050-7526;2050-7534;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	5.256	Times cited	5	Open Access	Not_Open_Access
	Notes	FWO projects G.0456.12; 50 G.0346.09N; Methusalem project "NANO			Approved	Most recent IF: 5.256; 2014 IF: 4.696
	Call Number	UA @ lucian @ c:irua:113734			Serial	1489
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	Author	Cabana, L.; Gonzalez-Campo, A.; Ke, X.; Van Tendeloo, G.; Nunez, R.; Tobias, G.
	Title	Efficient Chemical Modification of Carbon Nanotubes with Metallacarboranes			Type	A1 Journal article
	Year	2015	Publication	Chemistry: a European journal	Abbreviated Journal	Chem-Eur J
	Volume	21	Issue	21	Pages	16792-16795
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	As-produced single-walled carbon nanotubes (SWCNTs) tend to aggregate in bundles due to pi-pi interactions. Several approaches are nowadays available to debundle, at least partially, the nanotubes through surface modification by both covalent and noncovalent approaches. Herein, we explore different strategies to afford an efficient covalent functionalization of SWCNTs with cobaltabisdicarbollide anions. Aberration-corrected HRTEM analysis reveals the presence of metallacarboranes along the walls of the SWCNTs. This new family of materials presents an outstanding water dispersibility that facilitates its processability for potential applications.
	Address	Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus Universitari de la UAB. 08193, Bellaterra (Spain). gerard.tobias@icmab.es
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000366501600011	Publication Date	2015-10-06
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0947-6539;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	5.317	Times cited	5	Open Access
	Notes	The research leading to these results received financial support from MINECO (MAT2014-53500-R; CTQ2013-44670-R), Generalitat de Catalunya (2014/SGR/149), and from the European Commission under the FP7 ITN Marie-Curie Network programme RADDEL (grant agreement 290023), the Integrated Infrastructure Initiative No. 262348 European Soft Matter Infrastructure (ESMI) and the European Research Council, ERC Grant No 246791-COUNTATOMS. A.G.C. thanks the CSIC for the JAE-DOC grant.			Approved	Most recent IF: 5.317; 2015 IF: 5.731
	Call Number	c:irua:129215			Serial	3964
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	Author	Vereecke, B.; van der Veen, M.H.; Sugiura, M.; Kashiwagi, Y.; Ke, X.; Cott, D.J.; Hantschel, T.; Huyghebaert, C.; Tökei, Z.
	Title	Wafer-level electrical evaluation of vertical carbon nanotube bundles as a function of growth temperature			Type	A1 Journal article
	Year	2013	Publication	Japanese journal of applied physics	Abbreviated Journal	Jpn J Appl Phys
	Volume	52	Issue	42	Pages	04cn02-5
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	We have evaluated the resistance of carbon nanotubes (CNTs) grown at a CMOS-compatible temperature using a realistic integration scheme. The structural analysis of the CNTs by transmission electron microscopy (TEM) showed that the degree of graphitization decreased significantly when the growth temperature was decreased from 540 to 400 °C. The CNTs were integrated to form 150-nm-diameter vertical interconnects between a TiN layer and Cu metal trenches on 200 mm full wafers. Wafers with CNTs grown at low temperature were found to have a lower single-contact resistance than those produced at high temperatures. Thickness measurements showed that the low contact resistance is a result of small contact height. This height dependence is masking the impact of CNT graphitization quality on resistance. When benchmarking our results with data from the literature, a relationship between resistivity and growth temperature cannot be found for CNT-based vertical interconnects.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Kyoto	Editor
	Language		Wos	000320002400150	Publication Date	2013-03-22
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0021-4922;1347-4065;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	1.384	Times cited	5	Open Access
	Notes				Approved	Most recent IF: 1.384; 2013 IF: 1.057
	Call Number	UA @ lucian @ c:irua:108713			Serial	3902
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	Author	Vidick, D.; Ke, X.; Devillers, M.; Poleunis, C.; Delcorte, A.; Moggi, P.; Van Tendeloo, G.; Hermans, S.
	Title	Heterometal nanoparticles from Ru-based molecular clusters covalently anchored onto functionalized carbon nanotubes and nanofibers			Type	A1 Journal article
	Year	2015	Publication	Beilstein journal of nanotechnology	Abbreviated Journal	Beilstein J Nanotech
	Volume	6	Issue	6	Pages	1287-1297
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	Heterometal clusters containing Ru and Au, Co and/or Pt are anchored onto carbon nanotubes and nanofibers functionalized with chelating phosphine groups. The cluster anchoring yield is related to the amount of phosphine groups available on the nanocarbon surface. The ligands of the anchored molecular species are then removed by gentle thermal treatment in order to form nanoparticles. In the case of Au-containing clusters, removal of gold atoms from the clusters and agglomeration leads to a bimodal distribution of nanoparticles at the nanocarbon surface. In the case of Ru-Pt species, anchoring occurs without reorganization through a ligand exchange mechanism. After thermal treatment, ultrasmall (1-3 nm) bimetal Ru-Pt nanoparticles are formed on the surface of the nanocarbons. Characterization by high resolution transmission electron microscopy (HRTEM) and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) confirms their bimetal nature on the nanoscale. The obtained bimetal nanoparticles supported on nanocarbon were tested as catalysts in ammonia synthesis and are shown to be active at low temperature and atmospheric pressure with very low Ru loading.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000355908400001	Publication Date	2015-06-10
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2190-4286;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.127	Times cited	7	Open Access
	Notes	246791 Countatoms; 262348 Esmi			Approved	Most recent IF: 3.127; 2015 IF: 2.670
	Call Number	c:irua:126431			Serial	1420
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	Author	Li, H.; Zhang, L.; Li, L.; Wu, C.; Huo, Y.; Chen, Y.; Liu, X.; Ke, X.; Luo, J.; Van Tendeloo, G.
	Title	Two-in-one solution using insect wings to produce graphene-graphite films for efficient electrocatalysis			Type	A1 Journal article
	Year	2019	Publication	Nano Research	Abbreviated Journal	Nano Res
	Volume	12	Issue	1	Pages	33-39
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	Natural organisms contain rich elements and naturally optimized smart structures, both of which have inspired various innovative concepts and designs in human society. In particular, several natural organisms have been used as element sources to synthesize low-cost and environmentally friendly electrocatalysts for the oxygen reduction reaction (ORR) in fuel cells and metal-air batteries, which are clean energy devices. However, to date, no naturally optimized smart structures have been employed in the synthesis of ORR catalysts, including graphene-based materials. Here, we demonstrate a novel strategy to synthesize graphene-graphite films (GGFs) by heating butterfly wings coated with FeCl3 in N-2, in which the full power of natural organisms is utilized. The wings work not only as an element source for GGF generation but also as a porous supporting structure for effective nitrogen doping, two-dimensional spreading, and double-face exposure of the GGFs. These GGFs exhibit a half-wave potential of 0.942 V and a H2O2 yield of < 0.07% for ORR electrocatalysis; these values are comparable to those for the best commercial Pt/C and all previously reported ORR catalysts in alkaline media. This two-in-one strategy is also successful with cicada and dragonfly wings, indicating that it is a universal, green, and cost-effective method for developing high-performance graphene-based materials.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000453629900004	Publication Date	2018-08-30
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1998-0124	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	7.354	Times cited	7	Open Access	Not_Open_Access
	Notes	; The authors would like to thank Drs Qiang Wang and Wenjuan Yuan for useful discussions. This work was financially supported by the National Key R&D Program of China (No. 2017YFA0700104), the National Natural Science Foundation of China (Nos. 21601136 and 11404016), the National Program for Thousand Young Talents of China, Tianjin Municipal Education Commission, Tianjin Municipal Science and Technology Commission (No. 15JCYBJC52600), and the Fundamental Research Fund of Tianjin University of Technology. This work also made use of the resources of the National Center for Electron Microscopy in Beijing. ;			Approved	Most recent IF: 7.354
	Call Number	UA @ admin @ c:irua:156210			Serial	5265
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	Author	He, Z.; Ke, X.; Bals, S.; Van Tendeloo, G.
	Title	Direct evidence for the existence of multi-walled carbon nanotubes with hexagonal cross-sections			Type	A1 Journal article
	Year	2012	Publication	Carbon	Abbreviated Journal	Carbon
	Volume	50	Issue	7	Pages	2524-2529
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Carbon nanotubes (CNTs) with a polygonal cross-section have been paid increasing attention since their three-dimensional structure is related to specific physical properties, which are found to be different in comparison to CNTs with a circular cross-section. Here, we report the existence of novel multi-walled CNTs yielding walls with a rounded-hexagonal configuration. This structure was directly confirmed for the first time by both cross-sectional transmission electron microscopy and electron tomography. The morphology of the Fe catalytic particle also exhibits hexagonal characteristics, and is proposed as the origin of the formation of the rounded-hexagonal walls of the CNT. This observation is of great importance with respect to the design of polygonal (such as pentagonal or hexagonal) cross-sectional CNTs. By controlling the morphology of the catalytic nanoparticles it will be possible to grow CNTs with desired electronic and mechanical properties.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Oxford	Editor
	Language		Wos	000303038400015	Publication Date	2012-02-06
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0008-6223;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.337	Times cited	8	Open Access
	Notes	Fwo			Approved	Most recent IF: 6.337; 2012 IF: 5.868
	Call Number	UA @ lucian @ c:irua:96956			Serial	711
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	Author	Ribbens, S.; Beyers, E.; Schellens, K.; Mertens, M.; Ke, X.; Bals, S.; Van Tendeloo, G.; Meynen, V.; Cool, P.
	Title	Systematic evaluation of thermal and mechanical stability of different commercial and synthetic photocatalysts in relation to their photocatalytic activity			Type	A1 Journal article
	Year	2012	Publication	Microporous and mesoporous materials: zeolites, clays, carbons and related materials	Abbreviated Journal	Micropor Mesopor Mat
	Volume	156	Issue		Pages	62-72
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
	Abstract	The effect of thermal treatment and mechanical stress on the structural and photocatalytic properties of eight different (synthetic and commercial) photocatalysts has been thoroughly investigated. Different mesoporous Ti-based materials were prepared via surfactant based synthesis routes (e.g. Pluronic 123, CTMABr = Cetyltrimethylammonium bromide) or via template-free synthesis routes (e.g. trititanate nanotubes). Also, the stabilizing effect of the NaOH/NH4OH post-treatment on the templated mesoporous materials and their photocatalytic activity was investigated. Furthermore, the thermal and mechanical properties of commercially available titanium dioxides such as P25 Evonik® and Millenium PC500® were studied. The various photocatalysts were analyzed with N2-sorption, X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) to obtain information concerning the specific surface area, pore volume, crystal structure, morphology, phase transitions, etc. In general, results show that the NaOH post-treatment leads to an increased control of the crystallization process during calcination resulting in a higher thermal stability, but at the same time diminishes the photocatalytic activity. Mesoporous materials in which pre-synthesized nanoparticles are used as titania source have the best mechanical stability whereas the mechanical stability of the nanotubes is the most limited. At increased temperatures and pressures, the tested commercial titanium dioxides lose their superior photocatalytic activity caused by a decreased accessibility of the active sites. The observed changes in adsorption capacities and photocatalytic activities cannot be assigned to one single phenomenon. In this respect, it shows the need to define a general/standard method to compare different photocatalysts. Furthermore, it is shown that the photocatalytic properties do not necessarily deteriorate under thermal stress, but can be improved due to crystallization, even though the initial material is (partially) destroyed. It is shown that the usefulness of a specific type of photocatalyst strongly depends on the application and the temperature/pressure to which it needs to resist.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Amsterdam	Editor
	Language		Wos	000303625200010	Publication Date	2012-02-08
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1387-1811;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.615	Times cited	8	Open Access
	Notes	Fwo			Approved	Most recent IF: 3.615; 2012 IF: 3.365
	Call Number	UA @ lucian @ c:irua:96910			Serial	3466
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	Author	Li, J.; Pereira, P.J.; Yuan, J.; Lv, Y.-Y.; Jiang, M.-P.; Lu, D.; Lin, Z.-Q.; Liu, Y.-J.; Wang, J.-F.; Li, L.; Ke, X.; Van Tendeloo, G.; Li, M.-Y.; Feng, H.-L.; Hatano, T.; Wang, H.-B.; Wu, P.-H.; Yamaura, K.; Takayama-Muromachi, E.; Vanacken, J.; Chibotaru, L.F.; Moshchalkov, V.V.
	Title	Nematic superconducting state in iron pnictide superconductors			Type	A1 Journal article
	Year	2017	Publication	Nature communications	Abbreviated Journal	Nat Commun
	Volume	8	Issue	1	Pages	1880
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	Nematic order often breaks the tetragonal symmetry of iron-based superconductors. It arises from regular structural transition or electronic instability in the normal phase. Here, we report the observation of a nematic superconducting state, by measuring the angular dependence of the in-plane and out-of-plane magnetoresistivity of Ba 0.5 K 0.5 Fe 2 As 2 single crystals. We find large twofold oscillations in the vicinity of the superconducting transition, when the direction of applied magnetic field is rotated within the basal plane. To avoid the influences from sample geometry or current flow direction, the sample was designed as Corbino-shape for in-plane and mesa-shape for out-of-plane measurements. Theoretical analysis shows that the nematic superconductivity arises from the weak mixture of the quasi-degenerate s-wave and d-wave components of the superconducting condensate, most probably induced by a weak anisotropy of stresses inherent to single crystals.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000416933400002	Publication Date	2017-11-27
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2041-1723	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	12.124	Times cited	8	Open Access	OpenAccess
	Notes	The authors J.L., P.J.P., and J.Y. contributed equally to this work. J.L. and J.Y. designed the experiments. J.L., H.-L.F., K.Y., and E.T.-M. grew the single crystals. J.L., J.Y., Y.-Y.L., M.-P.J., D.L., M.-Y.L., T.H., H.-B.W., P.-H.W., K.Y., E.T.-M., J.V., and V.V.M. fabricated the devices and measured transport properties. J.L., Y.-Y.L., Z.-Q.L., Y.-J.L., J.-F.W., and L.L. studied on the pulsed high field measurements. X.K. and G.V.T. measured the low temperature TEM. All authors discussed the data. J.L., P.J.P., and L.F.C. proposed the model and simulated the results. J.L., P.J.P., K.Y., E.T.-M., and L.F.C. analyzed the data and prepared the manuscript.			Approved	Most recent IF: 12.124
	Call Number	EMAT @ emat @c:irua:147348			Serial	4772
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	Author	Song, H.-D.; Wu, Y.-F.; Yang, X.; Ren, Z.; Ke, X.; Kurttepeli, M.; Tendeloo, G.V.; Liu, D.; Wu, H.-C.; Yan, B.; Wu, X.; Duan, C.-G.; Han, G.; Liao, Z.-M.; Yu, D.
	Title	Asymmetric Modulation on Exchange Field in a Graphene/BiFeO₃Heterostructure by External Magnetic Field			Type	A1 Journal article
	Year	2018	Publication	Nano letters	Abbreviated Journal	Nano Lett
	Volume	18	Issue	4	Pages	2435-2441
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	Graphene, having all atoms on its surface, is favorable to extend the functions by introducing the spin–orbit coupling and magnetism through proximity effect. Here, we report the tunable interfacial exchange field produced by proximity coupling in graphene/BiFeO3 heterostructures. The exchange field has a notable dependence with external magnetic field, and it is much larger under negative magnetic field than that under positive magnetic field. For negative external magnetic field, interfacial exchange coupling gives rise to evident spin splitting for N ≠ 0 Landau levels and a quantum Hall metal state for N = 0 Landau level. Our findings suggest graphene/BiFeO3 heterostructures are promising for spintronics.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000430155900034	Publication Date	2018-04-11
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1530-6984	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	12.712	Times cited	9	Open Access	Not_Open_Access
	Notes	This work was supported by National Key Research and Development Program of China (No. 2016YFA0300802) and NSFC (Nos. 11774004 and 11604004). Ministry of Science and Technology of the People's Republic of China, 2016YFA0300802 ; National Natural Science Foundation of China, 11604004 11774004 ;			Approved	Most recent IF: 12.712
	Call Number	EMAT @ lucian @c:irua:150794			Serial	4923
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	Author	Ke, X.; Bittencourt, C.; Van Tendeloo, G.
	Title	Possibilities and limitations of advanced transmission electron microscopy for carbon-based nanomaterials			Type	A1 Journal article
	Year	2015	Publication	Beilstein journal of nanotechnology	Abbreviated Journal	Beilstein J Nanotech
	Volume	6	Issue	6	Pages	1541-1557
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	A major revolution for electron microscopy in the past decade is the introduction of aberration correction, which enables one to increase both the spatial resolution and the energy resolution to the optical limit. Aberration correction has contributed significantly to the imaging at low operating voltages. This is crucial for carbon-based nanomaterials which are sensitive to electron irradiation. The research of carbon nanomaterials and nanohybrids, in particular the fundamental understanding of defects and interfaces, can now be carried out in unprecedented detail by aberration-corrected transmission electron microscopy (AC-TEM). This review discusses new possibilities and limits of AC-TEM at low voltage, including the structural imaging at atomic resolution, in three dimensions and spectroscopic investigation of chemistry and bonding. In situ TEM of carbon-based nanomaterials is discussed and illustrated through recent reports with particular emphasis on the underlying physics of interactions between electrons and carbon atoms.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000357977300001	Publication Date	2015-07-16
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2190-4286;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.127	Times cited	10	Open Access
	Notes	246791 Countatoms			Approved	Most recent IF: 3.127; 2015 IF: 2.670
	Call Number	c:irua:126857			Serial	2682
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	Author	Chen, J.J.; Wang, Q.; Meng, J.; Ke, X.; Van Tendeloo, G.; Bie, Y.Q.; Liu, J.; Liu, K.; Liao, Z.M.; Sun, D.; Yu, D.;
	Title	Photovoltaic effect and evidence of carrier multiplication in graphene vertical homojunctions with asymmetrical metal contacts			Type	A1 Journal article
	Year	2015	Publication	ACS nano	Abbreviated Journal	Acs Nano
	Volume	9	Issue	9	Pages	8851-8858
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	Graphene exhibits exciting potentials for high-speed wideband photodetection and high quantum efficiency solar energy harvest because of its broad spectral absorption, fast photoelectric response, and potential carrier multiplication. Although photocurrent can be generated near a metalgraphene interface in lateral devices, the photoactive area is usually limited to a tiny one-dimensional line-like interface region. Here, we report photoelectric devices based on vertical graphene two-dimensional homojunction, which is fabricated via vertically stacking four graphene monolayers with asymmetric metal contacts. The devices show excellent photovoltaic output with excitation wavelength ranging from visible light to mid-infrared. The wavelength dependence of the internal quantum efficiency gives direct evidence of the carrier multiplication effect in graphene. The simple fabrication process, easy scale-up, large photoresponsive active area, and broadband response of the vertical graphene device are very promising for practical applications in optoelectronics and photovoltaics.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000361935800023	Publication Date	2015-08-15
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1936-0851;1936-086X;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	13.942	Times cited	11	Open Access
	Notes	246791 Countatoms			Approved	Most recent IF: 13.942; 2015 IF: 12.881
	Call Number	c:irua:127689			Serial	2615
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	Author	Li, J.; Ji, M.; Schwarz, T.; Ke, X.; Van Tendeloo, G.; Yuan, J.; Pereira, P.J.; Huang, Y.; Zhang, G.; Feng, H.L.; Yuan, Y.H.; Hatano, T.; Kleiner, R.; Koelle, D.; Chibotaru, L.F.; Yamaura, K.; Wang, H.B.; Wu, P.H.; Takayama-Muromachi, E.; Vanacken, J.; Moshchalkov, V.V.;
	Title	Local destruction of superconductivity by non-magnetic impurities in mesoscopic iron-based superconductors			Type	A1 Journal article
	Year	2015	Publication	Nature communications	Abbreviated Journal	Nat Commun
	Volume	6	Issue	6	Pages	7614
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	The determination of the pairing symmetry is one of the most crucial issues for the iron-based superconductors, for which various scenarios are discussed controversially. Non-magnetic impurity substitution is one of the most promising approaches to address the issue, because the pair-breaking mechanism from the non-magnetic impurities should be different for various models. Previous substitution experiments demonstrated that the non-magnetic zinc can suppress the superconductivity of various iron-based superconductors. Here we demonstrate the local destruction of superconductivity by non-magnetic zinc impurities in Ba0.5K0.5Fe2As2 by exploring phase-slip phenomena in a mesoscopic structure with 119 × 102 nm2 cross-section. The impurities suppress superconductivity in a three-dimensional Swiss cheese-like pattern with in-plane and out-of-plane characteristic lengths slightly below ~1.34 nm. This causes the superconducting order parameter to vary along abundant narrow channels with effective cross-section of a few square nanometres. The local destruction of superconductivity can be related to Cooper pair breaking by non-magnetic impurities.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000358857000007	Publication Date	2015-07-03
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2041-1723;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	12.124	Times cited	12	Open Access
	Notes	246791 Countatoms			Approved	Most recent IF: 12.124; 2015 IF: 11.470
	Call Number	c:irua:126677			Serial	1827
Permanent link to this record



	Author	Ke, X.; Bittencourt, C.; Bals, S.; Van Tendeloo, G.
	Title	Low-dose patterning of platinum nanoclusters on carbon nanotubes by focused-electron-beam-induced deposition as studied by TEM			Type	A1 Journal article
	Year	2013	Publication	Beilstein journal of nanotechnology	Abbreviated Journal	Beilstein J Nanotech
	Volume	4	Issue		Pages	77-86
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	Focused-electron-beam-induced deposition (FEBID) is used as a direct-write approach to decorate ultrasmall Pt nanoclusters on carbon nanotubes at selected sites in a straightforward maskless manner. The as-deposited nanostructures are studied by transmission electron microscopy (TEM) in 2D and 3D, demonstrating that the Pt nanoclusters are well-dispersed, covering the selected areas of the CNT surface completely. The ability of FEBID to graft nanoclusters on multiple sides, through an electron-transparent target within one step, is unique as a physical deposition method. Using high-resolution TEM we have shown that the CNT structure can be well preserved thanks to the low dose used in FEBID. By tuning the electron-beam parameters, the density and distribution of the nanoclusters can be controlled. The purity of as-deposited nanoclusters can be improved by low-energy electron irradiation at room temperature.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000314499700001	Publication Date	2013-02-04
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2190-4286;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.127	Times cited	12	Open Access
	Notes	262348 ESMI; 246791 COUNTATOMS; FWO G002410N; ESF Cost Action NanoTP MP0901			Approved	Most recent IF: 3.127; 2013 IF: 2.332
	Call Number	UA @ lucian @ c:irua:106187			Serial	1848
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	Author	Zhang, L.; Lin, B.-C.; Wu, Y.-F.; Wu, H.; Huang, T.-W.; Chang, C.-R.; Ke, X.; Kurttepeli, M.; Tendeloo, G.V.; Xu, J.; Yu, D.; Liao, Z.-M.
	Title	Electronic Coupling between Graphene and Topological Insulator Induced Anomalous Magnetotransport Properties			Type	A1 Journal article
	Year	2017	Publication	ACS nano	Abbreviated Journal	Acs Nano
	Volume	11	Issue	11	Pages	6277-6285
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	It has been theoretically proposed that the spin textures of surface states in a topological insulator can be directly transferred to graphene by means of the proximity effect, which is very important for realizing the two-dimensional topological insulator based on graphene. Here we report the anomalous magnetotransport properties of graphene-topological insulator Bi2Se3 heterojunctions, which are sensitive to the electronic coupling between graphene and the topological surface state. The coupling between the p_z orbitals of graphene and the p orbitals of the surface states on the Bi2Se3 bottom surface can be enhanced by applying a perpendicular negative magnetic field, resulting in a giant negative magnetoresistance at the Dirac point up to about -91%. Obvious resistances dip in the transfer curve at the Dirac point is also observed in the hybrid devices, which is consistent with theoretical predictions of the distorted Dirac bands with nontrivial spin textures inherited from the Bi2Se3 surface states.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000404808000110	Publication Date	2017-05-10
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1936-0851	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	13.942	Times cited	12	Open Access	OpenAccess
	Notes	; This work was supported by National Key Research and Development Program of China (Nos. 2016YFA0300802, 2013CB934600) and NSFC (No. 11234001). ;			Approved	Most recent IF: 13.942
	Call Number	EMAT @ emat @ c:irua:143192			Serial	4569
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	Author	Bittencourt, C.; Krüger, P.; Lagos, M.J.; Ke, X.; Van Tendeloo, G.; Ewels, C.; Umek, P.; Guttmann, P.
	Title	Towards atomic resolution in sodium titanate nanotubes using near-edge X-ray-absorption fine-structure spectromicroscopy combined with multichannel multiple-scattering calculations			Type	A1 Journal article
	Year	2012	Publication	Beilstein journal of nanotechnology	Abbreviated Journal	Beilstein J Nanotech
	Volume	3	Issue		Pages	789-797
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	Recent advances in near-edge X-ray-absorption fine-structure spectroscopy coupled with transmission X-ray microscopy (NEXAFS-TXM) allow large-area mapping investigations of individual nano-objects with spectral resolution up to E/Delta E = 104 and spatial resolution approaching 10 nm. While the state-of-the-art spatial resolution of X-ray microscopy is limited by nanostructuring process constrains of the objective zone plate, we show here that it is possible to overcome this through close coupling with high-level theoretical modelling. Taking the example of isolated bundles of hydrothermally prepared sodium titanate nanotubes ((Na,H)TiNTs) we are able to unravel the complex nanoscale structure from the NEXAFS-TXM data using multichannel multiple-scattering calculations, to the extent of being able to associate specific spectral features in the O K-edge and Ti L-edge with oxygen atoms in distinct sites within the lattice. These can even be distinguished from the contribution of different hydroxyl groups to the electronic structure of the (Na,H)TiNTs.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000311482400001	Publication Date	2012-11-23
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2190-4286;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.127	Times cited	13	Open Access
	Notes				Approved	Most recent IF: 3.127; 2012 IF: 2.374
	Call Number	UA @ lucian @ c:irua:105140			Serial	3684
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	Author	Zhong, R.; Peng, L.; de Clippel, F.; Gommes, C.; Goderis, B.; Ke, X.; Van Tendeloo, G.; Jacobs, P.A.; Sels, B.F.
	Title	An eco-friendly soft template synthesis of mesostructured silica-carbon nanocomposites for acid catalysis			Type	A1 Journal article
	Year	2015	Publication	ChemCatChem	Abbreviated Journal	Chemcatchem
	Volume	7	Issue	7	Pages	3047-3058
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The synthesis of ordered mesoporous silica-carbon composites was explored by employing TEOS and sucrose as the silica and carbon precursor respectively, and the triblock copolymer F127 as a structure-directing agent via an evaporation-induced self-assembly (EISA) process. It is demonstrated that the synthesis procedures allow for control of the textural properties and final composition of these silica-carbon nanocomposites via adjustment of the effective SiO2/C weight ratio. Characterization by SAXS, N-2 physisorption, HRTEM, TGA, and C-13 and Si-29 solid-state MAS NMR show a 2D hexagonal mesostructure with uniform large pore size ranging from 5.2 to 7.6nm, comprising of separate carbon phases in a continuous silica phase. Ordered mesoporous silica and non-ordered porous carbon can be obtained by combustion of the pyrolyzed nanocomposites in air or etching with HF solution, respectively. Sulfonic acid groups can be readily introduced to such kind of silica-carbon nanocomposites by a standard sulfonation procedure with concentrated sulfuric acid. Excellent acid-catalytic activities and selectivities for the dimerization of styrene to produce 1,3-diphenyl-1-butene and dimerization of -methylstyrene to unsaturated dimers were demonstrated with the sulfonated materials.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000361189400037	Publication Date	2015-09-03
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1867-3880; 1867-3899	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	4.803	Times cited	13	Open Access
	Notes				Approved	Most recent IF: 4.803; 2015 IF: 4.556
	Call Number	UA @ lucian @ c:irua:127836			Serial	4138
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	Author	Yan, Y.; Zhou, X.; Jin, H.; Li, C.-Z.; Ke, X.; Van Tendeloo, G.; Liu, K.; Yu, D.; Dressel, M.; Liao, Z.-M.
	Title	Surface-Facet-Dependent Phonon Deformation Potential in Individual Strained Topological Insulator Bi2Se3 Nanoribbons			Type	A1 Journal article
	Year	2015	Publication	ACS nano	Abbreviated Journal	Acs Nano
	Volume	9	Issue	9	Pages	10244-10251
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	Strain is an important method to tune the properties of topological insulators. For example, compressive strain can induce superconductivity in Bi2Se3 bulk material. Topological insulator nanostructures are the superior candidates to utilize the unique surface states due to the large surface to volume ratio. Therefore, it is highly desirable to monitor the local strain effects in individual topological insulator nanostructures. Here, we report the systematical micro-Raman spectra of single strained Bi2Se3 nanoribbons with different thicknesses and different surface facets, where four optical modes are resolved in both Stokes and anti-Stokes Raman spectral lines. A striking anisotropy of the strain dependence is observed in the phonon frequency of strained Bi2Se3 nanoribbons grown along the ⟨112̅0⟩ direction. The frequencies of the in-plane Eg2 and out-of-plane A1g1 modes exhibit a nearly linear blue-shift against bending strain when the nanoribbon is bent along the ⟨112̅0⟩ direction with the curved {0001} surface. In this case, the phonon deformation potential of the Eg2 phonon for 100 nm-thick Bi2Se3 nanoribbon is up to 0.94 cm–1/%, which is twice of that in Bi2Se3 bulk material (0.52 cm–1/%). Our results may be valuable for the strain modulation of individual topological insulator nanostructures.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Wos	000363915300079	Publication Date	2015-09-12
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1936-0851;1936-086X;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	13.942	Times cited	14	Open Access
	Notes	Y.Y. would like to thank Xuewen Fu for helpful discussions. This work was supported by MOST (Nos. 2013CB934600, 2013CB932602) and NSFC (Nos. 11274014, 11234001).			Approved	Most recent IF: 13.942; 2015 IF: 12.881
	Call Number	c:irua:129216			Serial	3963
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	Author	Bittencourt, C.; van Lier, G.; Ke, X.; Suarez-Martinez, I.; Felten, A.; Ghijsen, J.; Van Tendeloo, G.; Ewels, C.O.
	Title	Spectroscopy and defect identification for fluorinated carbon nanotubes			Type	A1 Journal article
	Year	2009	Publication	ChemPhysChem : a European journal of chemical physics and physical chemistry	Abbreviated Journal	Chemphyschem
	Volume	10	Issue	6	Pages	920-925
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Multi-wall carbon nanotubes (MWCNTs) were exposed to a CF4 radio-frequency (rf) plasma. High-resolution photoelectron spectroscopy shows that the treatment effectively grafts fluorine atoms onto the MWCNTs, altering the valence electronic states. Fluorine surface concentration can be tuned by varying the exposure time. Evaporation of gold onto MWCNTs is used to mark active site formation. High-resolution transmission electron microscopy coupled with density functional theory (DFT) modelling is used to characterise the surface defects formed, indicating that the plasma treatment does not etch the tube surface. We suggest that this combination of theory and microscopy of thermally evaporated gold atoms onto the CNT surface may be a powerful approach to characterise both surface defect density as well as defect type.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Weinheim	Editor
	Language		Wos	000265469200011	Publication Date	2009-03-05
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1439-4235;1439-7641;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.075	Times cited	14	Open Access
	Notes	Iuap; Fwo			Approved	Most recent IF: 3.075; 2009 IF: 3.453
	Call Number	UA @ lucian @ c:irua:77315			Serial	3073
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	Author	de Clippel, F.; Harkiolakis, A.; Vosch, T.; Ke, X.; Giebeler, L.; Oswald, S.; Houthoofd, K.; Jammaer, J.; Van Tendeloo, G.; Martens, J.A.; Jacobs, P.A.; Baron, G.V.; Sels, B.F.; Denayer, J.F.M.
	Title	Graphitic nanocrystals inside the pores of mesoporous silica : synthesis, characterization and an adsorption study			Type	A1 Journal article
	Year	2011	Publication	Microporous and mesoporous materials: zeolites, clays, carbons and related materials	Abbreviated Journal	Micropor Mesopor Mat
	Volume	144	Issue	1/3	Pages	120-133
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	This work presents a new carbonsilica hybrid material, denoted as CSM, with remarkable sorption properties. It consists of intraporous graphitic nanocrystals grown in the pores of mesoporous silica. CSM is obtained by a subtle incipient wetness impregnation of Al-containing mesoporous silica with furfuryl alcohol (FA)/hemelitol solutions. Both the volume match of the impregnation solution with that of the silica template pore volume, and the presence of Al3+ in the silica, are crucial to polymerize FA selectively inside the mesopores. Carbonization of the intraporous polymer was then performed by pyrolysis under He up to 1273 K. The resulting CSMs were examined by SEM, HRTEM, 27Al MAS NMR, N2 adsorption, XRD, TGA, TPD, XPS, pycnometry and Raman spectroscopy. Mildly oxidized graphitic-like carbon nanoblocks, consisting of a few graphene-like sheets, were thus identified inside the template mesopores. Random stacking of these carbon crystallites generates microporosity resulting in biporous materials at low carbon content and microporous materials at high carbon loadings. Very narrow pore distributions were obtained when pyrolysis was carried out under slow heating rate, viz. 1 K min−1. Adsorption and shape selective properties of the carbon filled mesoporous silica were studied by performing pulse chromatography and breakthrough experiments, and by measuring adsorption isotherms of linear and branched alkanes. Whereas the parent mesoporous silica shows unselective adsorption, their CSM analogues preferentially adsorb linear alkanes. The sorption capacity and selectivity can be adjusted by changing the pore size of the template or by varying the synthesis conditions. A relation between the carbon crystallites size and the shape selective behaviour of the corresponding CSM for instance is demonstrated. Most interestingly, CSM shows separation factors for linear and branched alkanes up to values comparable to those of zeolitic molecular sieves.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Amsterdam	Editor
	Language		Wos	000293435400016	Publication Date	2011-04-15
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1387-1811;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.615	Times cited	15	Open Access
	Notes				Approved	Most recent IF: 3.615; 2011 IF: 3.285
	Call Number	UA @ lucian @ c:irua:92325			Serial	1380
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	Author	Bittencourt, C.; Hitchock, A.P.; Ke, X.; Van Tendeloo, G.; Ewels, C.P.; Guttmann, P.
	Title	X-ray absorption spectroscopy by full-field X-ray microscopy of a thin graphite flake: Imaging and electronic structure via the carbon K-edge			Type	A1 Journal article
	Year	2012	Publication	Beilstein journal of nanotechnology	Abbreviated Journal	Beilstein J Nanotech
	Volume	3	Issue		Pages	345-350
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	We demonstrate that near-edge X-ray-absorption fine-structure spectra combined with full-field transmission X-ray microscopy can be used to study the electronic structure of graphite flakes consisting of a few graphene layers. The flake was produced by exfoliation using sodium cholate and then isolated by means of density-gradient ultracentrifugation. An image sequence around the carbon K-edge, analyzed by using reference spectra for the in-plane and out-of-plane regions of the sample, is used to map and spectrally characterize the flat and folded regions of the flake. Additional spectral features in both π and σ regions are observed, which may be related to the presence of topological defects. Doping by metal impurities that were present in the original exfoliated graphite is indicated by the presence of a pre-edge signal at 284.2 eV.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000303243400001	Publication Date	2012-04-25
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2190-4286;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.127	Times cited	15	Open Access
	Notes				Approved	Most recent IF: 3.127; 2012 IF: 2.374
	Call Number	UA @ lucian @ c:irua:97703			Serial	3924
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	Author	Ke, X.; Turner, S.; Quintana, M.; Hadad, C.; Montellano-López, A.; Carraro, M.; Sartorel, A.; Bonchio, M.; Prato, M.; Bittencourt, C.; Van Tendeloo, G.;
	Title	Dynamic motion of Ru-polyoxometalate ions (POMs) on functionalized few-layer graphene			Type	A1 Journal article
	Year	2013	Publication	Small	Abbreviated Journal	Small
	Volume	9	Issue	23	Pages	3922-3927
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	The interaction and stability of Ru4POM on few layer graphene via functional groups is investigated by time-dependent imaging using aberration-corrected transmission electron microscopy. The Ru4POM demonstrates dynamic motion on the graphene surface with its frequency and amplitude of rotation related to the nature of the functional group used. The stability of the Ru4POMgraphene hybrid corroborates its long-term robustness when applied to multielectronic catalytic processes.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Weinheim	Editor
	Language		Wos	000331282400003	Publication Date	2013-07-01
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1613-6810;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	8.643	Times cited	16	Open Access
	Notes	IAP-7; Countatoms;			Approved	Most recent IF: 8.643; 2013 IF: 7.514
	Call Number	UA @ lucian @ c:irua:115768			Serial	763
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	Author	Gengler, R.Y.N.; Toma, L.M.; Pardo, E.; Lloret, F.; Ke, X.; Van Tendeloo, G.; Gournis, D.; Rudolf, P.
	Title	Prussian blue analogues of reduced dimensionality			Type	A1 Journal article
	Year	2012	Publication	Small	Abbreviated Journal	Small
	Volume	8	Issue	16	Pages	2532-2540
	Keywords	A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
	Abstract	Mixed-valence polycyanides (Prussian Blue analogues) possess a rich palette of properties spanning from room-temperature ferromagnetism to zero thermal expansion, which can be tuned by chemical modifications or the application of external stimuli (temperature, pressure, light irradiation). While molecule-based materials can combine physical and chemical properties associated with molecular-scale building blocks, their successful integration into real devices depends primarily on higher-order properties such as crystal size, shape, morphology, and organization. Herein a study of a new reduced-dimensionality system based on Prussian Blue analogues (PBAs) is presented. The system is built up by means of a modified Langmuir-Blodgett technique, where the PBA is synthesized from precursors in a self-limited reaction on a clay mineral surface. The focus of this work is understanding the magnetic properties of the PBAs in different periodic, low-dimensional arrangements, and the influence of the “on surface” synthesis on the final properties and dimensionality of the system.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Weinheim	Editor
	Language		Wos	000307390300012	Publication Date	2012-07-03
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1613-6810;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	8.643	Times cited	17	Open Access
	Notes				Approved	Most recent IF: 8.643; 2012 IF: 7.823
	Call Number	UA @ lucian @ c:irua:101104			Serial	2736
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