“Plasmonic goldsilver alloy on TiO2 photocatalysts with tunable visible light activity”. Verbruggen SW, Keulemans M, Filippousi M, Flahaut D, Van Tendeloo G, Lacombe S, Martens JA, Lenaerts S, Applied catalysis : B : environmental 156, 116 (2014). http://doi.org/10.1016/j.apcatb.2014.03.027
Abstract: Adaptation of the photoresponse of anatase TiO2 to match the solar spectrum is an important scientific challenge. Modification of TiO2 with noble metal nanoparticles displaying surface plasmon resonance effects is one of the promising approaches. Surface plasmon resonance typically depends on chemical composition, size, shape and spatial organization of the metal nanoparticles in contact with TiO2. AuxAg(1 − x) alloy nanoparticles display strong composition-dependent surface plasmon resonance in the visible light region of the spectrum. In this work, a general strategy is presented to prepare plasmonic TiO2-based photocatalysts with a visible light response that can be accurately tuned over a broad range of the spectrum. The application as self-cleaning material toward the degradation of stearic acid is demonstrated for a plasmonic TiO2 photocatalyst displaying visible light photoactivity at the intensity maximum of solar light around 490 nm.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.446
Times cited: 84
DOI: 10.1016/j.apcatb.2014.03.027
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“Platinum particle size and support effects in NOx mediated carbon oxidation over platinum catalysts”. Villani K, Vermandel W, Smets K, Liang D, Van Tendeloo G, Martens JA, Environmental science &, technology 40, 2727 (2006). http://doi.org/10.1021/es051871h
Abstract: Platinum metal was dispersed on microporous, mesoporous, and nonporous support materials including the zeolites Na-Y, Ba-Y, Ferrierite, ZSM-22, ETS-10, and AlPO-11, alumina, and titania. The oxidation of carbon black loosely mixed with catalyst powder was monitored gravimetrically in a gas stream containing nitric oxide, oxygen, and water. The carbon oxidation activity of the catalysts was found to be uniquely related to the Pt dispersion and little influenced by support type. The optimum dispersion is around 3-4% corresponding to relatively large Pt particle sizes of 2040 nm. The carbon oxidation activity reflects the NO oxidation activity of the platinum catalyst, which reaches an optimum in the 20-40 nm Pt particle size range. The lowest carbon oxidation temperatures were achieved with platinum loaded ZSM-22 and AlPO-11 zeolite crystallites bearing platinum of optimum dispersion on their external surfaces.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.198
Times cited: 29
DOI: 10.1021/es051871h
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“Quantitative three-dimensional modeling of zeotile through discrete electron tomography”. Bals S, Batenburg KJ, Liang D, Lebedev O, Van Tendeloo G, Aerts A, Martens JA, Kirschhock CE, Journal of the American Chemical Society 131, 4769 (2009). http://doi.org/10.1021/ja8089125
Abstract: Discrete electron tomography is a new approach for three-dimensional reconstruction of nanoscale objects. The technique exploits prior knowledge of the object to be reconstructed, which results in an improvement of the quality of the reconstructions. Through the combination of conventional transmission electron microscopy and discrete electron tomography with a model-based approach, quantitative structure determination becomes possible. In the present work, this approach is used to unravel the building scheme of Zeotile-4, a silica material with two levels of structural order. The layer sequence of slab-shaped building units could be identified. Successive layers were found to be related by a rotation of 120°, resulting in a hexagonal space group. The Zeotile-4 material is a demonstration of the concept of successive structuring of silica at two levels. At the first level, the colloid chemical properties of Silicalite-1 precursors are exploited to create building units with a slablike geometry. At the second level, the slablike units are tiled using a triblock copolymer to serve as a mesoscale structuring agent.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Impact Factor: 13.858
Times cited: 58
DOI: 10.1021/ja8089125
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“Smart heating profiles for the synthesis of benzene bridged periodic mesoporous organosilicas”. Smeulders G, van Oers C, Van Havenbergh K, Houthoofd K, Mertens M, Martens JA, Bals S, Maes BUW, Meynen V, Cool P, Chemical engineering journal 175, 585 (2011). http://doi.org/10.1016/j.cej.2011.09.116
Abstract: In this study the effects of the heating rate and heating time on the formation of crystal-like benzene bridged periodic mesoporous organosilicas (PMOs) are investigated. The time needed to heat up an autoclave during the hydrothermal treatment has shown to be crucial in the synthesis of PMOs, while the total duration of heating gave rise to only minor differences. By choosing a smart heating profile, superior PMO materials can be obtained in a short time. Different heating profiles in a range from one minute to one hour are adopted by microwave equipment and compared with conventional heating methods. The heating rate has a large influence on the porosity characteristics and the uniformity of the obtained particles. Moreover, two new alternative synthetic strategies to adopt the smart heating profile are presented, in order to give some possible solutions for the expensive microwave equipment.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Organic synthesis (ORSY)
Impact Factor: 6.216
Times cited: 7
DOI: 10.1016/j.cej.2011.09.116
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“Synthesis and characterization of nanocrystal zeolite/mesoporous matrix composite material”. Gagea BC, Liang D, Van Tendeloo G, Martens JA, Jacobs PA, Studies in surface science and catalysis 162, 259 (2006). http://doi.org/10.1016/S0167-2991(06)80915-8
Keywords: P1 Proceeding; Electron microscopy for materials research (EMAT)
Times cited: 8
DOI: 10.1016/S0167-2991(06)80915-8
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“Synthesis and characterization of the new cyclosilicate hydrate (hexamethyleneimine)4.[Si8O16(OH)4].12H2O”. Verlooy PLH, Robeyns K, van Meervelt L, Lebedev OI, Van Tendeloo G, Martens JA, Kirschhock CEA, Microporous and mesoporous materials: zeolites, clays, carbons and related materials 130, 14 (2010). http://doi.org/10.1016/j.micromeso.2009.10.006
Abstract: A new cyclosilicate hydrate with composition (C6H14N)4·[Si8O16(OH)4]·12H2O was crystallized and the structure determined by single-crystal X-ray diffraction. The structure, described by the tetragonal space group I41/a, with unit cell dimensions of a = 39.2150(2) Å and c = 14.1553(2) Å, contains columns of hydrogen-bonded cubic octamer silicate anions. The space between silicate columns holds hydrogen-bonded water and protonated hexamethyleneimine molecules compensating the negative charge of the silicate. The crystal water can be removed resulting in a rearrangement of the columns into orthorhombic symmetry. Removal of the organic moiety causes amorphisation. Flash evacuation results in a new microporous material with pore volumes typical of a zeolite.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.615
Times cited: 5
DOI: 10.1016/j.micromeso.2009.10.006
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“Synthesis of highly stable pure-silica thin-walled hexagonally ordered mesoporous material”. Verlooy P, Aerts A, Lebedev OI, Van Tendeloo G, Kirschhock C, Martens JA, Chemical communications , 4287 (2009). http://doi.org/10.1039/b901796h
Abstract: Hexagonally ordered mesoporous silica with a very narrow mesopore size distribution and exceptionally high stability paired with unusually thin pore walls was prepared using piperidine and cetyltrimethylammonium bromide.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 17
DOI: 10.1039/b901796h
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“Synthesis of uniformly dispersed anatase nanoparticles inside mesoporous silica thin films via controlled breakup and crystallization of amorphous TiO2 deposited using atomic layer deposition”. Sree SP, Dendooven J, Masschaele K, Hamed HM, Deng S, Bals S, Detavernier C, Martens JA, Nanoscale 5, 5001 (2013). http://doi.org/10.1039/c3nr00594a
Abstract: Amorphous titanium dioxide was introduced into the pores of mesoporous silica thin films with 75% porosity and 12 nm average pore diameter via Atomic Layer Deposition (ALD) using alternating pulses of tetrakis(dimethylamino)titanium and water. Calcination provoked fragmentation of the deposited amorphous TiO2 phase and its crystallization into anatase nanoparticles inside the nanoporous film. The narrow particle size distribution of 4 ± 2 nm and the uniform dispersion of the particles over the mesoporous silica support were uniquely revealed using electron tomography. These anatase nanoparticle bearing films showed photocatalytic activity in methylene blue degradation. This new synthesis procedure of the anatase nanophase in mesoporous silica films using ALD is a convenient fabrication method of photocatalytic coatings amenable to application on very small as well as very large surfaces
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 7.367
Times cited: 22
DOI: 10.1039/c3nr00594a
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“TEM observation of aggregation steps in room-temperature silicalite-1 zeolite formation”. Liang D, Follens LRA, Aerts A, Martens JA, Van Tendeloo G, Kirschhock CEA, Journal of physical chemistry C 111, 14283 (2007). http://doi.org/10.1021/jp074960k
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.536
Times cited: 41
DOI: 10.1021/jp074960k
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“Tiling silicalite-1 nanoslabs into 3D mosaics”. Kremer SPB, Kirschhock CEA, Aerts A, Villani K, Martens JA, Lebedev OI, Van Tendeloo G, Advanced materials 15, 1705 (2003). http://doi.org/10.1002/adma.200305266
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 19.791
Times cited: 82
DOI: 10.1002/adma.200305266
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“Zeotile-2: a microporous analogue of MCM-48”. Kremer SPB, Kirschhock CEA, Aerts A, Aerts CA, Houthoofd KJ, Grobet PJ, Jacobs PA, Lebedev OI, Van Tendeloo G, Martens JA, Solid state sciences 7, 861 (2005). http://doi.org/10.1016/j.solidstatesciences.2005.01.021
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.811
Times cited: 10
DOI: 10.1016/j.solidstatesciences.2005.01.021
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“PDMS membranes containing ZIF-coated mesoporous silica spheres for efficient ethanol recovery via pervaporation”. Naik PV, Wee LH, Meledina M, Turner S, Li Y, Van Tendeloo G, Martens JA, Vankelecom IFJ, Journal of materials chemistry A : materials for energy and sustainability 4, 12790 (2016). http://doi.org/10.1039/C6TA04700A
Abstract: The design of functional micro- and mesostructured composite materials is significantly important for separation processes. Mesoporous silica is an attractive material for fast diffusion, while microporous zeolitic imidazolate frameworks (ZIFs) are beneficial for selective adsorption and diffusion. In this work, ZIF-71 and ZIF-8 nanocrystals were grown on the surface of mesoporous silica spheres (MSS) via the seeding and regrowth approach in order to obtain monodispersed MSS-ZIF-71 and MSS-ZIF-8 spheres with a particle size of 2-3 mm. These MSS-ZIF spheres were uniformly dispersed into a polydimethylsiloxane (PDMS) matrix to prepare mixed matrix membranes (MMMs). These MMMs were evaluated for the separation of ethanol from water via pervaporation. The pervaporation results reveal that the MSS-ZIF filled MMMs substantially improve the ethanol recovery in both aspects viz. flux and separation factor. These MMMs outperforms the unfilled PDMS membranes and the conventional carbon and zeolite filled MMMs. As expected, the mesoporous silica core allows very fast flow of the permeating compound, while the hydrophobic ZIF coating enhances the ethanol selectivity through its specific pore structure, hydrophobicity and surface chemistry. It can be seen that ZIF-8 mainly has a positive impact on the selectivity, while ZIF-71 enhances fluxes more significantly.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 8.867
Times cited: 26
DOI: 10.1039/C6TA04700A
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“1D-2D-3D Transformation Synthesis of Hierarchical Metal-Organic Framework Adsorbent for Multicomponent Alkane Separation”. Wee LH, Meledina M, Turner S, Van Tendeloo G, Zhang K, Marleny Rodriguez-Albelo L, Masala A, Bordiga S, Jiang J, Navarro JAR, Kirschhock CEA, Martens JA, Journal of the American Chemical Society 139, 819 (2017). http://doi.org/10.1021/JACS.6B10768
Abstract: A new hierarchical MOF consisting of Cu(II) centers connected by benzene-tricarboxylates (BTC) is prepared by thermoinduced solid transformation of a dense CuBTC precursor phase. The mechanism of the material formation has been thoroughly elucidated and revealed a transformation of a ribbon-like 1D building unit into 2D layers and finally a 3D network. The new phase contains excess copper, charge compensated by systematic hydroxyl groups, which leads to an open microporous framework with tunable permanent mesoporosity. The new phase is particularly attractive for molecular separation. Energy consumption of adsorptive separation processes can be lowered by using adsorbents that discriminate molecules based on adsorption entropy rather than enthalpy differences. In separation of a 11-component mixture of C-1-C-6 alkanes, the hierarchical phase outperforms the structurally related microporous HKUST-1 as well as silicate-based hierarchical materials. Grand canonical Monte Carlo (GCMC) simulation provides microscopic insight into the structural host-guest interaction, confirming low adsorption enthalpies and significant entropic contributions to the molecular separation. The unique three-dimensional hierarchical structure as well as the systematic presence of Cu(II) unsaturated coordination sites cause this exceptional behavior.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 33
DOI: 10.1021/JACS.6B10768
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“Activity versus selectivity in photocatalysis : morphological or electronic properties tipping the scale”. Keulemans M, Verbruggen SW, Hauchecorne B, Martens JA, Lenaerts S, Journal of catalysis 344, 221 (2016). http://doi.org/10.1016/J.JCAT.2016.09.033
Abstract: In this paper a structure-activity and structure-selectivity relation is established for three commercial TiO2 sources (P25, P90, and PC500). Morphological and electronic parameters of the photocatalysts are determined using widely applicable and inexpensive characterization procedures. More specifically, the electronic properties are rigorously characterized using an electron titration method yielding quantitative information on the amount of defect sites present in the catalyst. Surface photovoltage measurements on the other hand provide complementary information on the charge carrier recombination process. As model reaction, the degradation of a solid layer of stearic acid is studied using an in situ FTIR reaction cell that enables to investigate the catalyst surface and possible formation of reaction intermediates while the reactions are ongoing. We show that the order of photocatalytic conversion is PC500 > P90 > P25, matching the order of favorable morphological properties. In terms of selectivity to CO2 formation (complete mineralization), however, this trend is reversed: P25 > P90 > PC500, now matching the order of advantageous electronic properties, i.e. low charge carrier recombination and high charge carrier generation. With this we intend to provide new mechanistic insights using a wide variety of physical, (wet) chemical and operando analysis methods that aid the development of performant (self-cleaning) photocatalytic materials.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.844
Times cited: 10
DOI: 10.1016/J.JCAT.2016.09.033
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“The benefit of glass bead supports for efficient gas phase photocatalysis : case study of a commercial and a synthesised photocatalyst”. Verbruggen SW, Ribbens S, Tytgat T, Hauchecorne B, Smits M, Meynen V, Cool P, Martens JA, Lenaerts S, Chemical engineering journal 174, 318 (2011). http://doi.org/10.1016/J.CEJ.2011.09.038
Abstract: In the field of photocatalytic air purification, the immobilisation of catalyst particles on support surfaces without loss of photon efficiency is an important challenge. Therefore, an immobilisation method involving a one-step suspension coating of pre-synthesised photocatalysts on glass beads was applied. The various benefits are exemplified in the gas phase photodegradation of ethylene. Coating of glass beads is easy, fast, cheap and offers a more efficient alternative to bulk catalyst pellets. Furthermore, this coating procedure allows to use porous, pre-synthesised catalysts to their full potential, as the surface area and morphology of the initial powder is barely altered after coating, in strong contrast to pelletising. With this technique it became possible to study the gas phase photocatalytic activity of commercial titanium dioxide, trititanate nanotubes and mixed phase anatase/trititanate nanotubes in a packed bed reactor towards the degradation of ethylene without changing the catalyst properties. Coating of glass beads with the photocatalyst revealed the superior activity of the as-prepared nanotubes, compared to TiO2 Aerolyst® 7710 in gaseous phase.
Keywords: A1 Journal article; Engineering sciences. Technology; Laboratory of adsorption and catalysis (LADCA); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.216
Times cited: 39
DOI: 10.1016/J.CEJ.2011.09.038
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“Controllable nitrogen doping in as deposited TiO2 film and its effect on post deposition annealing”. Deng S, Verbruggen SW, Lenaerts S, Martens JA, Van den Berghe S, Devloo-Casier K, Devulder W, Dendoover J, Deduytsche D, Detavernier C, Journal of vacuum science and technology: A: vacuum surfaces and films 32, 01a123 (2014). http://doi.org/10.1116/1.4847976
Abstract: In order to narrow the band gap of TiO2, nitrogen doping by combining thermal atomic layer deposition (TALD) of TiO2 and plasma enhanced atomic layer deposition (PEALD) of TiN has been implemented. By altering the ratio between TALD TiO2 and PEALD TiN, the as synthesized TiOxNy films showed different band gaps (from 1.91 eV to 3.14 eV). In situ x-ray diffraction characterization showed that the crystallization behavior of these films changed after nitrogen doping. After annealing in helium, nitrogen doped TiO2 films crystallized into rutile phase while for the samples annealed in air a preferential growth of the anatase TiO2 along (001) orientation was observed. Photocatalytic tests of the degradation of stearic acid were done to evaluate the effect of N doping on the photocatalytic activity.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 1.374
Times cited: 10
DOI: 10.1116/1.4847976
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“Elucidating the photocatalytic degradation pathway of acetaldehyde : an FTIR in situ study under atmospheric conditions”. Hauchecorne B, Terrens D, Verbruggen S, Martens JA, van Langenhove H, Demeestere K, Lenaerts S, Applied catalysis : B : environmental 106, 630 (2011). http://doi.org/10.1016/J.APCATB.2011.06.026
Abstract: In this paper, new insights of the photocatalytic oxidation pathway of acetaldehyde are obtained by means of an in-house constructed FTIR in situ reactor. It is shown that there are generally three different intermediates present: acetic acid, formic acid and formaldehyde. By means of FTIR in situ spectroscopy, this study revealed that these intermediates are bound on the TiO2 surface in different ways, resulting in the presence of more intermediate species, such as molecularly adsorbed acetic acid, bidentate acetate, molecularly adsorbed formic acid, monodentate formate, bidentate formate, formaldehyde and dioxymethylene. Furthermore, spectroscopic evidence is obtained concerning the formation of 3-hydroxybutanal and crotonaldehyde upon adsorption of acetaldehyde on TiO2 prior to UV illumination. The presented results thus give new insights in the photocatalytic oxidation pathway of acetaldehyde.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.446
Times cited: 46
DOI: 10.1016/J.APCATB.2011.06.026
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“Factors driving the activity of commercial titanium dioxide powders towards gas phase photocatalytic oxidation of acetaldehyde”. Verbruggen SW, Masschaele K, Moortgat E, Korany TE, Hauchecorne B, Martens JA, Lenaerts S, Catalysis science &, technology 2, 2311 (2012). http://doi.org/10.1039/C2CY20123B
Abstract: The photocatalytic activity of two commercial titanium dioxide powders (Cristal Global, Millennium PC500 and Evonik, P25) is compared towards acetaldehyde degradation in the gas phase. In contrast to the extensive literature available, we found a higher activity for the PC500 than for the P25 coating. Here, we present a comprehensive characterization of the bulk and surface properties of both powders. Our comparison shows that the material properties that dominate the overall photocatalytic activity in gas phase differ from those required for the photodegradation of water-borne pollutants.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 5.773
Times cited: 33
DOI: 10.1039/C2CY20123B
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“Harvesting hydrogen gas from air pollutants with an un-biased gas phase photo-electrochemical cell”. Verbruggen SW, Van Hal M, Bosserez T, Rongé, J, Hauchecorne B, Martens JA, Lenaerts S, Chemsuschem 10, 1413 (2017). http://doi.org/10.1002/CSSC.201601806
Abstract: The concept of an all-gas-phase photo-electrochemical cell (PEC) producing hydrogen gas from volatile organic contaminated gas and light is presented. Without applying any external bias, organic contaminants are degraded and hydrogen gas is produced in separate electrode compartments. The system works most efficiently with organic pollutants in inert carrier gas. In the presence of oxygen gas, the cell performs less efficiently but still significant photocurrents are generated, showing the cell can be run on organic contaminated air. The purpose of this study is to demonstrate new application opportunities of PEC technology and to encourage further advancement toward photo-electrochemical remediation of air pollution with the attractive feature of simultaneous energy recovery and pollution abatement.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 7.226
Times cited: 6
DOI: 10.1002/CSSC.201601806
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“A non-aqueous synthesis of TiO2SiO2 composites in supercritical CO2 for the photodegradation of pollutants”. Jammaer J, Aprile C, Verbruggen SW, Lenaerts S, Pescarmona PP, Martens JA, Chemsuschem 4, 1457 (2011). http://doi.org/10.1002/CSSC.201100059
Abstract: Titania/silica composites with different Ti/Si ratios are synthesized via a nonconventional synthesis route. The synthesis involves non-aqueous reaction of metal alkoxides and formic acid at 75 °C in supercritical carbon dioxide. The as-prepared composite materials contain nanometer-sized anatase crystallites and amorphous silica. Large specific surface areas are obtained. The composites are evaluated in the photocatalytic degradation of phenol in aqueous medium, and in the elimination of acetaldehyde from air. The highest photocatalytic activity in both processes is achieved with a composite containing 40 wt % TiO2.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 7.226
Times cited: 15
DOI: 10.1002/CSSC.201100059
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“Photocatalysis assisted simultaneous carbon oxidation and NOx reduction”. Liao L, Heylen S, Sree SP, Vallaey B, Keulemans M, Lenaerts S, Roeffaers MBJ, Martens JA, Applied catalysis : B : environmental 202, 381 (2017). http://doi.org/10.1016/J.APCATB.2016.09.042
Abstract: Photocatalysis assisted oxidation of carbon black was performed using TiO2 photocatalyst under UV illumination in an atmosphere with NO, O-2 and water vapor at 150 degrees C. Carbon is oxidized mainly to CO2 while NO is selectively converted to N-2. Enhanced O-2 and NO concentrations have a positive effect on the carbon oxidation rate. At a concentration of 3000 ppm NO and 13.3% O-2 in the gas phase the carbon oxidation rate reaches 2.3 mu g(carbon)/mg(TiO2) h, at a formal electron/photon quantum efficiency of 0.019. HR SEM images reveal uniform gradual reduction of the carbon particle size irrespective of the distance to TiO2 photocatalyst particles in the presence of NO, O-2 and H2O. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.446
Times cited: 11
DOI: 10.1016/J.APCATB.2016.09.042
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“Photocatalytic carbon oxidation with nitric oxide”. Liao L, Heylen S, Vallaey B, Keulemans M, Lenaerts S, Roeffaers MBJ, Martens JA, Applied catalysis : B : environmental 166, 374 (2015). http://doi.org/10.1016/J.APCATB.2014.11.051
Abstract: The photocatalytic oxidation of carbon black on TiO2 using nitric oxide as an oxidizing agent was investigated. Layer-wise deposited carbon and TiO2 powder was illuminated with UVA light in the presence of NO at parts per million concentrations in dry and hydrated carrier gas at a temperature of 150 degrees C. Carbon was photocatalytically converted mainly into CO2, and NO mainly into N-2. Carbon oxidation rates of 7.2 mu g/h/mgTiO(2) were achieved in the presence of 3000 ppm NO. Under these experimental conditions in the absence of molecular oxygen, formation of surface nitrates causing TiO2 photocatalyst deactivation is suppressed. Addition of water enhances surface nitrate formation and catalyst deactivation. NO and carbon particulate matter are air pollutants emitted by diesel engines. Elimination of soot collected on a diesel particulate filter through oxidation is a demanding reaction requiring temperatures in excess of 250 degrees C. The present study opens perspectives for a low-temperature regeneration strategy for the diesel particulate filter that simultaneously performs DeNO(x) reactions. (C) 2014 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.446
Times cited: 5
DOI: 10.1016/J.APCATB.2014.11.051
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“Plasma-enhanced atomic layer deposition of silver using Ag(fod)(PEt3) and NH3-plasma”. Minjauw MM, Solano E, Sree SP, Asapu R, Van Daele M, Ramachandran RK, Heremans G, Verbruggen SW, Lenaerts S, Martens JA, Detavernier C, Dendooven J, Chemistry of materials 29, 7114 (2017). http://doi.org/10.1021/ACS.CHEMMATER.7B00690
Abstract: A plasma-enhanced atomic layer deposition (ALD) process using the Ag(fod)(PEt3) precursor [(triethylphosphine)(6,6,7,7,8,8,8-heptafluoro-2,2-dimethy1-3,5-octanedionate)silver(I)] in combination with NH3-plasma is reported. The steady growth rate of the reported process (0.24 +/- 0.03 nm/cycle) was found to be 6 times larger than that of the previously reported Ag ALD process based on the same precursor in combination with H-2-plasma (0.04 +/- 0.02 nm/cycle). The ALD characteristics of the H-2-plasma and NH3-plasma processes were verified. The deposited Ag films were polycrystalline face-centered cubic Ag for both processes. The film morphology was investigated by ex situ scanning electron microscopy and grazing-incidence small-angle X-ray scattering, and it was found that films grown with the NH3-plasma process exhibit a much higher particle areal density and smaller particle sizes on oxide substrates compared to those deposited using the H-2-plasma process. This control over morphology of the deposited Ag is important for applications in catalysis and plasmonics. While films grown with the H-2-plasma process had oxygen impurities (similar to 9 atom %) in the bulk, the main impurity for the NH3-plasma process was nitrogen (similar to 7 atom %). In situ Fourier transform infrared spectroscopy experiments suggest that these nitrogen impurities are derived from NH surface groups generated during the NH3-plasma, which interact with the precursor molecules during the precursor pulse. We propose that the reaction of these surface groups with the precursor leads to additional deposition of Ag atoms during the precursor pulse compared to the H-2-plasma process, which explains the enhanced growth rate of the NH3-plasma process.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 9.466
Times cited: 9
DOI: 10.1021/ACS.CHEMMATER.7B00690
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“Predicting the surface plasmon resonance wavelength of gold-silver alloy nanoparticles”. Verbruggen SW, Keulemans M, Martens JA, Lenaerts S, The journal of physical chemistry: C : nanomaterials and interfaces 117, 19142 (2013). http://doi.org/10.1021/JP4070856
Abstract: Gold-silver alloy nanoparticles display surface plasmon resonance (SPR) over a broad range of the UV-vis spectrum. We propose a model to predict the SPR wavelength of gold-silver alloy colloids based on the combined effect of alloy composition and particle size. The SPR wavelength is derived from extinction spectra simulated using available experimental dielectric constant data and accounts for particle size by applying Mie theory. Comparison of calculated values with experimental data evidences the accuracy of the model. The new SPR wavelength estimation tool will be of particular interest for developing dedicated bimetallic plasmonic nanostructures.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.536
Times cited: 51
DOI: 10.1021/JP4070856
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“Surface photovoltage measurements : a quick assessment of the photocatalytic activity?”.Verbruggen SW, Dirckx JJJ, Martens JA, Lenaerts S, Catalysis today 209, 215 (2013). http://doi.org/10.1016/J.CATTOD.2012.11.010
Abstract: Surface photovoltage (SPV) measurements can contribute to a better understanding of electronic properties of photocatalysts under illumination. Direct linking of SPV data to the actual photocatalytic activity remains troublesome. This work aims to discuss SPV measurements from a photocatalytic point of view. By means of several application-based scenarios we illustrate that the trend between SPV and photocatalysis strongly depends on parameters such as the crystal structure, surface modifications, morphology and humidity. This makes the interpretation far from straightforward.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.636
Times cited: 8
DOI: 10.1016/J.CATTOD.2012.11.010
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“Cost-effectiveness analysis to assess commercial TiO2 photocatalysts for acetaldehyde degradation in air”. Verbruggen SW, Tytgat T, Van Passel S, Martens JA, Lenaerts S, Chemicke zvesti 68, 1273 (2014). http://doi.org/10.2478/S11696-014-0557-3
Abstract: In the commercialisation of photocatalytic air purifiers, the performance as well as the cost of the catalytic material plays an important role. Where most comparative studies only regard the photocatalytic activity as a decisive parameter, in this study both activity and cost are taken into account. Using a cost-effectiveness analysis, six different commercially available TiO2-based catalysts are evaluated in terms of their activities in photocatalytic degradation of acetaldehyde as a model reaction for indoor air purification.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 1.258
Times cited: 10
DOI: 10.2478/S11696-014-0557-3
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“High-performance CO2-selective hybrid membranes by exploiting MOF-breathing effects”. Kertik A, Wee LH, Şentosun K, Navarro JAR, Bals S, Martens JA, Vankelecom IFJ, Acs Applied Materials &, Interfaces 12, 2952 (2020). http://doi.org/10.1021/ACSAMI.9B17820
Abstract: Conventional CO2 separation in the petrochemical industry via cryogenic distillation or amine-based absorber-stripper units is energy-intensive and environmentally unfriendly. Membrane-based gas separation technology, in contrast, has contributed significantly to the development of energy-efficient systems for processes such as natural gas purification. The implementation of commercial polymeric membranes in gas separation processes is restricted by their permeability-selectivity trade-off and by their insufficient thermal and chemical stability. Herein, we present the fabrication of a Matrimid-based membrane loaded with a breathing metal-organic framework (MOF) (NH2-MIL-53(Al)) which is capable of separating binary CO2/CH4 gas mixtures with high selectivities without sacrificing much of its CO2 permeabilities. NH2-MIL-53(Al) crystals were embedded in a polyimide (PI) matrix, and the mixed-matrix membranes (MMMs) were treated at elevated temperatures (up to 350 degrees C) in air to trigger PI cross-linking and to create PI-MOF bonds at the interface to effectively seal the grain boundary. Most importantly, the MOF transitions from its narrow-pore form to its large-pore form during this treatment, which allows the PI chains to partly penetrate the pores and cross-link with the amino functions at the pore mouth of the NH2-MIL-53(Al) and stabilizes the open-pore form of NH2-MIL-53(Al). This cross-linked MMM, with MOF pore entrances was made more selective by the anchored PI-chains and achieves outstanding CO2/CH4 selectivities. This approach provides significant advancement toward the design of selective MMMs with enhanced thermal and chemical stabilities which could also be applicable for other potential applications, such as separation of hydrocarbons (olefin/paraffin or isomers), pervaporation, and solvent-resistant nanofiltration.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 9.5
Times cited: 26
DOI: 10.1021/ACSAMI.9B17820
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“Towards green ammonia synthesis through plasma-driven nitrogen oxidation and catalytic reduction”. Hollevoet L, Jardali F, Gorbanev Y, Creel J, Bogaerts A, Martens JA, Angewandte Chemie-International Edition (2020). http://doi.org/10.1002/ANIE.202011676
Abstract: Ammonia is an industrial large-volume chemical, with its main application in fertilizer production. It also attracts increasing attention as a green-energy vector. Over the past century, ammonia production has been dominated by the Haber-Bosch process, in which a mixture of nitrogen and hydrogen gas is converted to ammonia at high temperatures and pressures. Haber-Bosch processes with natural gas as the source of hydrogen are responsible for a significant share of the global CO(2)emissions. Processes involving plasma are currently being investigated as an alternative for decentralized ammonia production powered by renewable energy sources. In this work, we present the PNOCRA process (plasma nitrogen oxidation and catalytic reduction to ammonia), combining plasma-assisted nitrogen oxidation and lean NO(x)trap technology, adopted from diesel-engine exhaust gas aftertreatment technology. PNOCRA achieves an energy requirement of 4.6 MJ mol(-1)NH(3), which is more than four times less than the state-of-the-art plasma-enabled ammonia synthesis from N(2)and H(2)with reasonable yield (>1 %).
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 16.6
Times cited: 1
DOI: 10.1002/ANIE.202011676
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