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“Sampling real-time atomic dynamics in metal nanoparticles by combining experiments, simulations, and machine learning”. Cioni M, Delle Piane M, Polino D, Rapetti D, Crippa M, Arslan Irmak E, Van Aert S, Bals S, Pavan GM, Advanced Science , 1 (2024). http://doi.org/10.1002/ADVS.202307261
Abstract: Even at low temperatures, metal nanoparticles (NPs) possess atomic dynamics that are key for their properties but challenging to elucidate. Recent experimental advances allow obtaining atomic-resolution snapshots of the NPs in realistic regimes, but data acquisition limitations hinder the experimental reconstruction of the atomic dynamics present within them. Molecular simulations have the advantage that these allow directly tracking the motion of atoms over time. However, these typically start from ideal/perfect NP structures and, suffering from sampling limits, provide results that are often dependent on the initial/putative structure and remain purely indicative. Here, by combining state-of-the-art experimental and computational approaches, how it is possible to tackle the limitations of both approaches and resolve the atomistic dynamics present in metal NPs in realistic conditions is demonstrated. Annular dark-field scanning transmission electron microscopy enables the acquisition of ten high-resolution images of an Au NP at intervals of 0.6 s. These are used to reconstruct atomistic 3D models of the real NP used to run ten independent molecular dynamics simulations. Machine learning analyses of the simulation trajectories allow resolving the real-time atomic dynamics present within the NP. This provides a robust combined experimental/computational approach to characterize the structural dynamics of metal NPs in realistic conditions. Experimental and computational techniques are bridged to unveil atomic dynamics in gold nanoparticles (NPs), using annular dark-field scanning transmission electron microscopy and molecular dynamics simulations informed by machine learning. The approach provides unprecedented insights into the real-time structural behaviors of NPs, merging state-of-the-art techniques to accurately characterize their dynamics under realistic conditions. image
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 15.1
DOI: 10.1002/ADVS.202307261
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“Single-layered imine-linked porphyrin-based two-dimensional covalent organic frameworks targeting CO₂, reduction”. Arisnabarreta N, Hao Y, Jin E, Salame A, Muellen K, Robert M, Lazzaroni R, Van Aert S, Mali KS, De Feyter S, Advanced energy materials (2024). http://doi.org/10.1002/AENM.202304371
Abstract: The reduction of carbon dioxide (CO2) using porphyrin-containing 2D covalent organic frameworks (2D-COFs) catalysts is widely explored nowadays. While these framework materials are normally fabricated as powders followed by their uncontrolled surface heterogenization or directly grown as thin films (thickness >200 nm), very little is known about the performance of substrate-supported single-layered (approximate to 0.5 nm thickness) 2D-COFs films (s2D-COFs) due to its highly challenging synthesis and characterization protocols. In this work, a fast and straightforward fabrication method of porphyrin-containing s2D-COFs is demonstrated, which allows their extensive high-resolution visualization via scanning tunneling microscopy (STM) in liquid conditions with the support of STM simulations. The as-prepared single-layered film is then employed as a cathode for the electrochemical reduction of CO2. Fe porphyrin-containing s2D-COF@graphite used as a single-layered heterogeneous catalyst provided moderate-to-high carbon monoxide selectivity (82%) and partial CO current density (5.1 mA cm(-2)). This work establishes the value of using single-layered films as heterogene ous catalysts and demonstrates the possibility of achieving high performance in CO2 reduction even with extremely low catalyst loadings.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 27.8
DOI: 10.1002/AENM.202304371
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“Stabilizing perovskite Pb(Mg0.33Nb0.67)O3-PbTiO3 thin films by fast deposition and tensile mismatched growth template”. Ni S, Houwman E, Gauquelin N, Chezganov D, Van Aert S, Verbeeck J, Rijnders G, Koster G, ACS applied materials and interfaces 16, 12744 (2024). http://doi.org/10.1021/ACSAMI.3C16241
Abstract: Because of its low hysteresis, high dielectric constant, and strong piezoelectric response, Pb(Mg1/3Nb2/3)O-3-PbTiO3 (PMN-PT) thin films have attracted considerable attention for the application in PiezoMEMS, field-effect transistors, and energy harvesting and storage devices. However, it remains a great challenge to fabricate phase-pure, pyrochlore-free PMN-PT thin films. In this study, we demonstrate that a high deposition rate, combined with a tensile mismatched template layer can stabilize the perovskite phase of PMN-PT films and prevent the nucleation of passive pyrochlore phases. We observed that an accelerated deposition rate promoted mixing of the B-site cation and facilitated relaxation of the compressively strained PMN-PT on the SrTiO3 (STO) substrate in the initial growth layer, which apparently suppressed the initial formation of pyrochlore phases. By employing La-doped-BaSnO3 (LBSO) as the tensile mismatched buffer layer, 750 nm thick phase-pure perovskite PMN-PT films were synthesized. The resulting PMN-PT films exhibited excellent crystalline quality close to that of the STO substrate.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 9.5
DOI: 10.1021/ACSAMI.3C16241
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“Terahertz magneto-optical properties of Nitrogen-doped diamond”. Xiao H, Wen H, Xu W, Cheng Y, Zhang J, Cheng X, Xiao Y, Ding L, Li H, He B, Peeters FM, Infrared physics and technology 138, 105237 (2024). http://doi.org/10.1016/J.INFRARED.2024.105237
Abstract: Nitrogen-doped diamond (N-D) is one of the most important carbon-based electronic and optical materials. Here we study the terahertz (THz) magneto-optical (MO) properties of N-D grown by microwave plasma-enhanced chemical vapor deposition. The optical microscope, SEM, XRD, Raman spectrum, FTIR spectroscopy and XPS are used for the characterization of N-D samples. Applying THz time-domain spectroscopy (TDS), in combination with the polarization test and the presence of magnetic field in Faraday geometry, THz MO transmissions through N-D are measured from 0 to 8 T at 80 K. The complex right- and left-handed circular transmission coefficients and MO conductivities for N-D are obtained accordingly. Through fitting the experimental results with theoretical formulas of the dielectric constant and MO conductivities for an electron gas, we are able to determine magneto-optically the key electronic parameters of N-D, such as the static dielectric constant epsilon b, the electron density ne, the electronic relaxation time tau, the electronic localization factor alpha and, particularly, the effective electron mass m* obtained under non-resonant condition. The dependence of these parameters upon magnetic field is examined and analyzed. We find that the MO conductivities of N-D can be described rightly by the MO Drude-Smith formulas developed by us previously. It is shown that N-doping and the presence of the magnetic field can lead towards the larger epsilon b and heavier m* in diamond, while ne/tau/alpha in N-D decreases/increases/decreases with increasing magnetic field. The results obtained from this work are benefit to us in gaining an in-depth understanding of the electronic and optoelectronic properties of N-D.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.3
DOI: 10.1016/J.INFRARED.2024.105237
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“Two new members of the covalent organic frameworks family : crystalline 2D-oxocarbon and 3D-borocarbon structures”. Hassani N, Movafegh-Ghadirli A, Mahdavifar Z, Peeters FM, Neek-Amal M, Computational materials science 241, 1 (2024). http://doi.org/10.1016/J.COMMATSCI.2024.113022
Abstract: Oxocarbons, known for over two centuries, have recently revealed a long-awaited facet: two-dimensional crystalline structures. Employing an intelligent global optimization algorithm (IGOA) alongside densityfunctional calculations, we unearthed a quasi -flat oxocarbon (C 6 0 6 ), featuring an oxygen -decorated hole, and a novel 3D-borocarbon. Comparative analyses with recently synthesized isostructures, such as 2D -porous carbon nitride (C 6 N 6 ) and 2D -porous boroxine (B 6 0 6 ), highlight the unique attributes of these compounds. All structures share a common stoichiometry of X 6 Y 6 (which we call COF-66), where X = B, C, and Y = B, N, O (with X not equal Y), exhibiting a 2D -crystalline structure, except for borocarbon C 6 B 6 , which forms a 3D crystal. In our comprehensive study, we conducted a detailed exploration of the electronic structure of X 6 Y 6 compounds, scrutinizing their thermodynamic properties and systematically evaluating phonon stability criteria. With expansive surface areas, diverse pore sizes, biocompatibility, pi-conjugation, and distinctive photoelectric properties, these structures, belonging to the covalent organic framework (COF) family, present enticing prospects for fundamental research and hold potential for biosensing applications.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.3
DOI: 10.1016/J.COMMATSCI.2024.113022
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“Unconventional superconducting diode effects via antisymmetry and antisymmetry breaking”. Li C, Lyu Y-Y, Yue W-C, Huang P, Li H, Li T, Wang C-G, Yuan Z, Dong Y, Ma X, Tu X, Tao T, Dong S, He L, Jia X, Sun G, Kang L, Wang H, Peeters FM, Milošević, MV, Wu P, Wang Y-L, Nano letters 24, 4108 (2024). http://doi.org/10.1021/ACS.NANOLETT.3C05008
Abstract: Symmetry breaking plays a pivotal role in unlocking intriguing properties and functionalities in material systems. For example, the breaking of spatial and temporal symmetries leads to a fascinating phenomenon: the superconducting diode effect. However, generating and precisely controlling the superconducting diode effect pose significant challenges. Here, we take a novel route with the deliberate manipulation of magnetic charge potentials to realize unconventional superconducting flux-quantum diode effects. We achieve this through suitably tailored nanoengineered arrays of nanobar magnets on top of a superconducting thin film. We demonstrate the vital roles of inversion antisymmetry and its breaking in evoking unconventional superconducting effects, namely a magnetically symmetric diode effect and an odd-parity magnetotransport effect. These effects are nonvolatilely controllable through in situ magnetization switching of the nanobar magnets. Our findings promote the use of antisymmetry (breaking) for initiating unconventional superconducting properties, paving the way for exciting prospects and innovative functionalities in superconducting electronics.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 10.8
DOI: 10.1021/ACS.NANOLETT.3C05008
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“Control of proton transport and hydrogenation in double-gated graphene”. Tong J, Fu Y, Domaretskiy D, Della Pia F, Dagar P, Powell L, Bahamon D, Huang S, Xin B, Costa Filho RN, Vega LF, Grigorieva IV, Peeters FM, Michaelides A, Lozada-Hidalgo M, Nature 630, 619 (2024). http://doi.org/10.1038/s41586-024-07435-8
Abstract: The basal plane of graphene can function as a selective barrier that is permeable to protons but impermeable to all ions and gases, stimulating its use in applications such as membranes, catalysis and isotope separation. Protons can chemically adsorb on graphene and hydrogenate it, inducing a conductor–insulator transition that has been explored intensively in graphene electronic devices. However, both processes face energy barriersand various strategies have been proposed to accelerate proton transport, for example by introducing vacancies, incorporating catalytic metalsor chemically functionalizing the lattice. But these techniques can compromise other properties, such as ion selectivity or mechanical stability. Here we show that independent control of the electric field,<italic>E</italic>, at around 1 V nm<sup>−1</sup>, and charge-carrier density,<italic>n</italic>, at around 1 × 10<sup>14</sup> cm<sup>−2</sup>, in double-gated graphene allows the decoupling of proton transport from lattice hydrogenation and can thereby accelerate proton transport such that it approaches the limiting electrolyte current for our devices. Proton transport and hydrogenation can be driven selectively with precision and robustness, enabling proton-based logic and memory graphene devices that have on–off ratios spanning orders of magnitude. Our results show that field effects can accelerate and decouple electrochemical processes in double-gated 2D crystals and demonstrate the possibility of mapping such processes as a function of<italic>E</italic>and<italic>n</italic>, which is a new technique for the study of 2D electrode–electrolyte interfaces.
Keywords: A1 Journal Article; Condensed Matter Theory (CMT) ;
Impact Factor: 64.8
DOI: 10.1038/s41586-024-07435-8
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“Improving Molecule–Metal Surface Reaction Networks Using the Meta-Generalized Gradient Approximation: CO2Hydrogenation”. Cai Y, Michiels R, De Luca F, Neyts E, Tu X, Bogaerts A, Gerrits N, The Journal of Physical Chemistry C 128, 8611 (2024). http://doi.org/10.1021/acs.jpcc.4c01110
Abstract: Density functional theory is widely used to gain insights into molecule−metal surface reaction networks, which is important for a better understanding of catalysis. However, it is well-known that generalized gradient approximation (GGA)
density functionals (DFs), most often used for the study of reaction networks, struggle to correctly describe both gas-phase molecules and metal surfaces. Also, GGA DFs typically underestimate reaction barriers due to an underestimation of the selfinteraction energy. Screened hybrid GGA DFs have been shown to reduce this problem but are currently intractable for wide usage. In this work, we use a more affordable meta-GGA (mGGA) DF in combination with a nonlocal correlation DF for the first time to study and gain new insights into a catalytically important surface
reaction network, namely, CO2 hydrogenation on Cu. We show that the mGGA DF used, namely, rMS-RPBEl-rVV10, outperforms typical GGA DFs by providing similar or better predictions for metals and molecules, as well as molecule−metal surface adsorption
and activation energies. Hence, it is a better choice for constructing molecule−metal surface reaction networks.
Keywords: A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 3.7
DOI: 10.1021/acs.jpcc.4c01110
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“Ab initio study of the adsorption of O, O2, H2O and H2O2 on UO2 surfaces using DFT+U and non-collinear magnetism”. Arts I, Saniz R, Baldinozzi G, Leinders G, Verwerft M, Lamoen D, Journal of Nuclear Materials 599, 155249 (2024). http://doi.org/10.1016/j.jnucmat.2024.155249
Abstract: In order to model correctly the corrosion of spent nuclear fuel under disposal conditions, it is important to understand its behavior in the presence of oxidants. To advance in this direction, we consider the oxidation of UO2. We investigate computationally the adsorption of various species on its three most stable surfaces: (111), (110), and (100), with emphasis on incorporating a full non-collinear PBE+U approach. Various species, namely O, O2, H2O and H2O2 are considered due to their relevance for the oxidation of UO2. The dissociation energy and an estimate for the dissociation barrier for O2 were obtained, using the preferred adsorption configurations of O and O2. The adsorption configurations for H2O in our study compare well with previous studies that used collinear approximations, both in terms of relative stability of configurations and bond lengths. Differences in adsorption energies were found, which may be important for reaction kinetics. Dissociative reactions in which the water molecule splits in hydrogen and hydroxyl occur only on one of the three surfaces. The hydrogen further reacts with a surface oxygen to also form a hydroxyl group. Not surprisingly, we find that H2O2 binds more strongly to the three surfaces than water (lower formation energy), and similar to H2O adsorption, dissociative reactions may occur. The dissociated hydrogen reacts with a surface oxygen to form a hydroxyl group and the hydroperoxyl molecule binds with a surface uranium. Our study, which includes a detailed study of electron transfer, magnetic structure and the preferred adsorption configurations, gives insight into the uranium oxidation states and the influence of surface geometry on adsorption. The findings contribute to a more comprehensive understanding of the early stages of UO2 oxidation.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 3.1
DOI: 10.1016/j.jnucmat.2024.155249
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“Cs3Bi2Br9 nanoparticles decorated C3N4 nanotubes composite photocatalyst for highly selective oxidation of benzylic alcohol”. Ding Y, Wang C, Bandaru S, Pei L, Zheng R, Hau Ng Y, Arenas Esteban D, Bals S, Zhong J, Hofkens J, Van Tendeloo G, Roeffaers MBJ, Chen L-H, Su B-L, Journal of Colloid and Interface Science 672, 600 (2024). http://doi.org/10.1016/j.jcis.2024.06.017
Abstract: Solar-light driven oxidation of benzylic alcohols over photocatalysts endows significant prospects in value-added organics evolution owing to its facile, inexpensive and sustainable process. However, the unsatisfactory performance of actual photocatalysts due to the inefficient charge separation, low photoredox potential and sluggish surface reaction impedes the practical application of this process. Herein, we developed an innovative Z-Scheme Cs3BiBr9 nanoparticles@porous C3N4 tubes (CBB-NP@P-tube-CN) heterojunction photocatalyst for highly selective benzyl alcohol oxidation. Such composite combining increased photo-oxidation potential, Z-Scheme charge migration route as well as the structural advantages of porous tubular C3N4 ensures the accelerated mass and ions diffusion kinetics, the fast photoinduced carriers dissociation and sufficient photoredox potentials. The CBB-NP@P-tube-CN photocatalyst demonstrates an exceptional performance for selective photo-oxidation of benzylic alcohol into benzaldehyde with 19, 14 and 3 times higher benzylic alcohols conversion rate than those of C3N4 nanotubes, Cs3Bi2Br9 and Cs3Bi2Br9@bulk C3N4 photocatalysts, respectively. This work offers a sustainable photocatalytic system based on lead-free halide perovskite toward large scale solar-light driven value-added chemicals production.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 9.9
DOI: 10.1016/j.jcis.2024.06.017
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“Plasma Catalysis Modeling: How Ideal Is Atomic Hydrogen for Eley–Rideal?”.Michiels R, Gerrits N, Neyts E, Bogaerts A, The Journal of Physical Chemistry C 128, 11196 (2024). http://doi.org/10.1021/acs.jpcc.4c02193
Abstract: Plasma catalysis is an emerging technology, but a lot of questions about the underlying surface mechanisms remain unanswered. One of these questions is how important Eley−Rideal (ER) reactions are, next to Langmuir−Hinshelwood reactions. Most plasma catalysis kinetic models predict ER reactions to be important and sometimes even vital for the surface chemistry. In this work, we take a critical look at how ER reactions involving H radicals are incorporated in kinetic models describing CO2 hydrogenation and NH3 synthesis. To this end, we construct potential energy surface (PES) intersections, similar to elbow plots constructed for dissociative chemisorption. The results of the PES intersections are in agreement with ab initio molecular dynamics (AIMD) findings in literature while being computationally much cheaper. We find that, for the reactions studied here, adsorption is more probable than a reaction via the hot atom (HA) mechanism, which in turn is more probable than a reaction via the ER mechanism. We also conclude that kinetic models of plasma-catalytic systems tend to overestimate the importance if ER reactions. Furthermore, as opposed to what is often assumed in kinetic models, the choice of catalyst will influence the ER reaction probability. Overall, the description of ER reactions is too much “ideal” in models. Based on our indings, we make a number of recommendations on how to incorporate ER reactions in kinetic models to avoid overestimation of their importance.
Keywords: A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 3.7
DOI: 10.1021/acs.jpcc.4c02193
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“Defect Engineering of MoTe2via Thiol Treatment for Type III van der Waals Heterojunction Phototransistor”. Jeong Y, Han B, Tamayo A, Claes N, Bals S, Samorì, P, ACS Nano 18, 18334 (2024). http://doi.org/10.1021/acsnano.4c02207
Abstract: Molybdenum ditelluride (MoTe2) nanosheets have displayed intriguing physicochemical properties and opto-electric characteristics as a result of their tunable and
small band gap (Eg ∼ 1 eV), facilitating concurrent electron and hole transport. Despite the numerous efforts devoted to the development of p-type MoTe2 field-effect transistors (FETs), the presence of tellurium (Te) point vacancies has caused serious reliability issues. Here, we overcome this major
limitation by treating the MoTe2 surface with thiolated molecules to heal Te vacancies. Comprehensive materials and electrical characterizations provided unambiguous evidence for the efficient chemisorption of butanethiol. Our thiol-treated MoTe2 FET exhibited a 10-fold increase in hole current and a positive threshold voltage shift of 25 V, indicative of efficient hole carrier doping. We demonstrated that our powerful molecular engineering strategy can be extended to the controlled formation of van der Waals heterostructures by developing an n-SnS2/thiol-MoTe2 junction FET (thiol-JFET). Notably, the thiol-JFET exhibited a significant negative photoresponse with a responsivity of 50 A W−1 and a fast response time of 80 ms based on band-to-band tunneling. More interestingly, the
thiol-JFET displayed a gate tunable trimodal photodetection comprising two photoactive modes (positive and negative photoresponse) and one photoinactive mode. These findings underscore the potential of molecular engineering approaches in
enhancing the performance and functionality of MoTe2-based nanodevices as key components in advanced 2D-based optoelectronics.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 17.1
DOI: 10.1021/acsnano.4c02207
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“Insight in NO synthesis in a gliding arc plasma via gas temperature and density mapping by laser-induced fluorescence”. Manaigo F, Chatterjee A, Bogaerts A, Snyders R, Plasma Sources Science and Technology 33, 075005 (2024). http://doi.org/10.1088/1361-6595/ad5df5
Abstract: A gliding arc (GA) plasma, operating at atmospheric pressure in a gas mixture of 50% N<sub>2</sub>and 50% O<sub>2</sub>, is studied using laser-induced fluorescence spectroscopy. The main goal is to determine the two-dimensional distribution of both the gas temperature and the NO ground state density in the afterglow. As GA plasma discharges at atmospheric pressure normally produce rather high NO<sub><italic>x</italic></sub>densities, the high concentration of relevant absorbers, such as NO, may impose essential restrictions for the use of ‘classical’ laser-induced fluorescence methods (dealing with excitation in the bandhead vicinity), as the laser beam would be strongly absorbed along its propagation in the afterglow. Since this was indeed the case for the studied discharge, an approach dealing with laser-based excitation of separate rotational lines is proposed. In this case, due to a non-saturated absorption regime, simultaneous and reliable measurements of both the NO density and the gas temperature (using a reference fitting spectrum) are possible. The proposed method is applied to provide a two-dimensional map for both the NO density and the gas temperature at different plasma conditions. The results show that the input gas flow rate strongly alters the plasma shape, which appears as an elongated column at low input gas flow rate and spreads laterally as the flow rate increases. Finally, based on temperature map analysis, a clear correlation between the gas temperature and NO concentration is found. The proposed method may be interesting for the plasma-chemical analysis of discharges with high molecular production yields, where knowledge of both molecular concentration and gas temperature is required.
Keywords: A1 Journal Article; plasma nitrogen fixation, gliding arc plasmatron, laser-induced fluorescence, afterglow rotational temperature, afterglow NO concentration; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 3.8
DOI: 10.1088/1361-6595/ad5df5
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“Plasma-based conversion of CO2 and CH4 into syngas: A dive into the effect of adding water”. Wanten B, Gorbanev Y, Bogaerts A, Fuel 374, 132355 (2024). http://doi.org/10.1016/j.fuel.2024.132355
Abstract: Plasma technology can play a vital role in the electrification and decarbonization of chemical processes. In this work, we carried out the bi-reforming of methane (BRM), producing syngas out of H2O vapor and the greenhouse gases CO2 and CH4, in an atmospheric pressure glow discharge reactor. Compared to dry reforming of methane (DRM), the addition of H2O helps in counteracting soot formation, and thus avoids severe destabilization of the generated plasma. A mixture of 14–41-45 vol% (CO2-CH4-H2O) leads to the overall best results in terms of stable plasma and performance metrics. We obtained a CO2 and CH4 conversion of 49 % and 74 %, respectively, at a SEI of 210 kJ/mol. The energy cost is 390 kJ/mol converted reactants, which is below the target defined for plasmabased syngas production to be competitive with other technologies. Moreover, we reached CO and H2 yields of
59 % and 49 %, and a syngas ratio (SR) of 2, which is ideal for further methanol synthesis.
Keywords: A1 Journal Article; Plasma Bi-reforming of methane Atmospheric pressure glow discharge Hydrogen-rich syngas; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 7.4
DOI: 10.1016/j.fuel.2024.132355
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“In SituStudy of the Activation Process of MOF-74 Using Three-Dimensional Electron Diffraction”. Quintelier M, Hajizadeh A, Zintler A, Gonçalves BF, Fernández de Luis R, Esrafili Dizaji L, Vande Velde CML, Wuttke S, Hadermann J, Chemistry of Materials (2024). http://doi.org/10.1021/acs.chemmater.4c01153
Abstract: Metal–organic framework (MOF)-74 is known for its effectiveness in selectively capturing carbon dioxide (CO2). Especially the Zn and Cu versions of MOF-74 show high efficiency of this material for CO2. However, the activation of this MOF, which is a crucial step for its utilization, is so far not well understood. Here, we are closing the knowledge gap by examining the activation using, for the first time in the MOF, three-dimensional electron diffraction (3DED) during in situ heating. The use of state-of-the-art direct electron detectors enables rapid acquisition and minimal exposure times, therefore minimizing beam damage to the very electron beam-sensitive MOF material. The activation process of Zn-MOF-74 and Cu-MOF-74 is systematically studied in situ, proving the creation of open metal sites. Differences in thermal stability between Zn-MOF-74 and Cu-MOF-74 are attributed to the strength of the metal–oxygen bonds and Jahn–Teller distortions. In the case of Zn-MOF-74, we observe previously unknown remaining electrostatic potentials inside the MOF pores, which indicate the presence of remaining atoms that might impede gas flow throughout the structure when using the MOF for absorption purposes. We believe our study exemplifies the significance of employing advanced characterization techniques to enhance our material understanding, which is a crucial step for unlocking the full potential of MOFs in various applications.
Keywords: A1 Journal Article; 3DED; MOFs; in situ; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 8.6
DOI: 10.1021/acs.chemmater.4c01153
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“Direct visualization of ligands on gold nanoparticles in a liquid environment”. Pedrazo-Tardajos A, Claes N, Wang D, Sánchez-Iglesias A, Nandi P, Jenkinson K, De Meyer R, Liz-Marzán LM, Bals S, Nature Chemistry (2024). http://doi.org/10.1038/s41557-024-01574-1
Abstract: The interaction among Au nanoparticles, their surface ligands and the solvent critically influences the properties of nanoparticles. Despite employing spectroscopic and scattering techniques to investigate their ensemble structure, a comprehensive understanding at the nanoscale remains elusive. Electron microscopy enables characterization of the local structure and composition but is limited by insufficient contrast, electron beam sensitivity and ultra-high vacuum, which prevent the investigation of dynamic aspects. Here we show that, by exploiting high-quality graphene liquid cells, we can overcome these limitations and investigate the structure of the ligand shell around the Au nanoparticles, as well as the ligand-Au interface in a liquid environment. Using this graphene liquid cell, we visualize the anisotropy, composition and dynamics of ligand distribution at the Au nanorod surface. Our results indicate a micellar model for the surfactant organisation. This work opens up a reliable and direct visualization of ligand distribution around colloidal nanoparticles.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 21.8
DOI: 10.1038/s41557-024-01574-1
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“Effect of O2on Plasma-Based Dry Reforming of Methane: Revealing the Optimal Gas Composition via Experiments and Modeling of an Atmospheric Pressure Glow Discharge”. Maerivoet S, Wanten B, De Meyer R, Van Hove M, Van Alphen S, Bogaerts A, ACS Sustainable Chemistry &, Engineering 12, 11419 (2024). http://doi.org/10.1021/acssuschemeng.4c04283
Abstract: Plasma technology is gaining increasing interest for the conversion of greenhouse gases, such as CO2 and CH4, into value-added chemicals using (renewable) electricity. In this paper, we study the effect of O2 addition to the combined conversion of CO2 and CH4 in an atmospheric pressure glow discharge plasma. This process is called “oxidative CO2 reforming of methane”, and we search for the optimal gas mixing ratio in terms of conversion, energy cost, product output and plasma stability. A mixing ratio of 42.5:42.5:15 CO2/CH4/O2 yields the best performance, with a CO2 and CH4 conversion of 50 and 74%, respectively, and an energy cost as low as 2 eV molecule−1 (corresponding to 7.9 kJ L−1 and 190 kJ mol−1), i.e., clearly below the target defined to be competitive with other technologies. The syngas components (CO and H2) are the most important products, with a syngas ratio, H2/CO, being 0.8. Plasma destabilization at high CH4 fractions due to solid carbon formation is the limiting factor for further improving this syngas ratio. The solid carbon material is found to be contaminated with steel particles originating from the electrode material, rendering it unappealing as a side product. Therefore, O2 addition helps to remove the carbon formation. Besides the experiments, we developed a 2D axisymmetric fluid dynamics model, which can successfully predict the experimental trends in conversion, product composition and temperatures, while providing unique insights in the formation of CxHy species.
Keywords: A1 Journal Article; plasma-based conversion, thermal plasma, syngas production, CO2 conversion, CH4 conversio; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 8.4
DOI: 10.1021/acssuschemeng.4c04283
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“Organic Molecular Glues to Design Three-Dimensional Cubic Nano-assemblies of Magnetic Nanoparticles”. Chowdhury MS, Esteban DA, Amin R, Román-Freijeiro C, Rösch EL, Etzkorn M, Schilling M, Ludwig F, Bals S, Salgueiriño V, Lak A, Chemistry of Materials 36, 6865 (2024). http://doi.org/10.1021/acs.chemmater.4c00770
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 8.6
DOI: 10.1021/acs.chemmater.4c00770
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“Insight on Zn-Al LDH as electrocatalyst for CO2 reduction reaction: An in-situ ATR-IR study”. Cavallo M, Dosa M, Nakazato R, Porcaro NG, Signorile M, Quintelier M, Hadermann J, Bordiga S, Rosero-Navarro NC, Tadanaga K, Crocellà, V, Bonino F, Journal of CO2 Utilization 83, 102804 (2024). http://doi.org/10.1016/j.jcou.2024.102804
Abstract: Electrochemical reduction of CO2 (CO2RR) is expected to play a key role among the various strategies being explored to limit global warming. In this scenario, Layered Double Hydroxides (LDHs) are emerging as a promising class of electrocatalysts to replace the most used noble metals. In this work three Zn-Al LDH with different Zn2+/Al3+ ratio were synthesized and characterized by means of XRD, STEM-EDX and HR-TEM. Their suitability for CO2RR to CO was assessed by means of a custom-made three-compartment cell, showing an increase in CO selectivity by decreasing the Zn2+/Al3+ ratio. The CO2 interaction with the samples was firstly
characterized by means of volumetric adsorption measurements, exhibiting an increase in capture capacity by decreasing the Zn2+/Al3+ ratio. The evolution of the samples in interaction with a CO2-saturated liquid flow was then deeply investigated by means of in-situ ATR-IR spectroscopy. The samples displayed a different evolution in the vibrational region of the carbonate-like species (1800–1200 cm???? 1). To better discriminate the different carbonate cyclohexane was also employed. A definitive assignment of the main IR bands of the carbonate was
carried out by studying the spectral behavior of the different bands observed in the ATR-IR experiments and by comparing these results with the existing literature. Interestingly, Zn-Al 1:2 LDH, the most efficient electrocatalyst for CO2RR, is also the sole sample exhibiting a higher monodentate to total bidentate carbonates ratio, suggesting that the existence of a higher content of low coordination oxygen anions with stronger basic character can influence the final catalytic activity.
Keywords: A1 Journal Article; In-situ ATR-IR spectroscopy; Layered Double Hydroxide; CO2 reduction reaction; Electrocatalysis; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 7.7
DOI: 10.1016/j.jcou.2024.102804
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“Plasma-catalytic direct oxidation of methane to methanol over Cu-MOR: Revealing the zeolite-confined Cu2+ active sites”. Lv H, Meng S, Cui Z, Li S, Li D, Gao X, Guo H, Bogaerts A, Yi Y, Chemical Engineering Journal 496, 154337 (2024). http://doi.org/10.1016/j.cej.2024.154337
Abstract: Efficient methane conversion to methanol remains a significant challenge in chemical industry. This study investigates the direct oxidation of methane to methanol under mild conditions, employing a synergy of nonthermal plasma and Cu-MOR (Copper-Mordenite) catalysts. Catalytic tests demonstrate that the Cu-MOR IE-3 catalyst (i.e., prepared by three cycles of ion exchange) exhibits superior catalytic performance (with 51 % methanol selectivity and 7.9 % methane conversion). Conversely, the Cu-MOR catalysts prepared via wetness impregnation tend to over-oxidize CH4 to CO and CO2. Through systematic catalyst characterizations (XRD, TPR, UV–Vis, HRTEM, XPS), we elucidate that ion exchange mainly leads to the formation of zeolite-confined Cu2+ species, while wetness impregnation predominantly results in CuO particles. Based on the catalytic performance, catalyst characterizations and in-situ FTIR spectra, we conclude that zeolite-confined Cu2+ species serve as the active sites for plasma-catalytic direct oxidation of methane to methanol.
Keywords: A1 Journal Article; Direct oxidation Methanol production Plasma catalysis Copper-mordenite catalysts; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 15.1
DOI: 10.1016/j.cej.2024.154337
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“Synergy or Antagonism? Exploring the Interplay of SnO2and an N-OMC Carbon Capture Medium for the Electrochemical CO2Reduction toward Formate”. Van Daele K, Balalta D, Hoekx S, Jacops R, Daems N, Altantzis T, Pant D, Breugelmans T, ACS Applied Energy Materials 7, 5517 (2024). http://doi.org/10.1021/acsaem.4c00994
Abstract: Closing the anthropogenic carbon cycle by means of the sustainable electrochemical CO2 reduction (eCO2R) toward formate (FA) is a promising strategy for CO2 abatement, clearing the path toward a carbon neutral future. Currently, three possible reaction pathways have been identified for the eCO2R toward FA, all of which are initiated by the adsorption of CO2 on the electrocatalyst’s surface. Therefore, a possible strategy to enhance the availability of CO2 near the active sites is to combine an active electrocatalyst material (here, SnO2) with a known carbon capture medium (here, nitrogen-doped ordered mesoporous carbon (N-OMC)). SnO2 was introduced in situ during the N-OMC synthesis, yielding SnO2-N-OMCs. We approached the state of the art for Sn-based N-doped carbon electrocatalysts in terms of performance under industrially relevant currents with an average FEFA of 59% for SnO2-N-OMC (6) and 61% for SnO2-N-OMC (2). Moreover, the SnO2-N-OMC electrocatalysts require a low overpotential, courtesy of the N-OMC support, compared to the state of the art, for the selective conversion of CO2 toward FA at the industrially relevant current density of 100 mA cm–2. Additionally, the 24 h stability of the best performing SnO2-N-OMC electrocatalysts is explored, and pulverization/agglomeration and in situ SnO2 reduction are identified as major degradation pathways, allowing future research to be steered more accurately toward more stable Sn-based electrocatalysts for the eCO2R toward FA. An optimal combination of both the SnO2 species and the N-OMC carbon capture medium could result in a synergistic effect, especially when utilization of the N-OMC support material is optimized to morphologically stabilize the SnO2 active species.
Keywords: A1 Journal Article; nitrogen-doped ordered mesoporous carbon, SnO2, degradation pathways, electrochemical CO2 reduction, formate; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 6.4
DOI: 10.1021/acsaem.4c00994
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“Genomic oropharyngeal Neisseria surveillance detects MALDI-TOF MS species misidentifications and reveals a novel Neisseria cinerea clade”. de Block T, De Baetselier I, Van den Bossche D, Abdellati S, Gestels Z, Laumen JGE, Van Dijck C, Vanbaelen T, Claes N, Vandelannoote K, Kenyon C, Harrison O, Santhini Manoharan-Basil S, Journal of Medical Microbiology 73 (2024). http://doi.org/10.1099/jmm.0.001871
Abstract: Introduction. Commensal Neisseria spp. are highly prevalent in the oropharynx as part of the healthy microbiome. N. meningitidis can colonise the oropharynx too from where it can cause invasive meningococcal disease. To identify N. meningitidis, clinical microbiology laboratories often rely on Matrix Assisted Laser Desorption/Ionisation Time of Flight Mass Spectrometry (MALDI-TOF MS).
Hypothesis/Gap statement. N. meningitidis may be misidentified by MALDI-TOF MS.
Aim. To conduct genomic surveillance of oropharyngeal Neisseria spp. in order to: (i) verify MALDI-TOF MS species identification, and (ii) characterize commensal Neisseria spp. genomes.
Methodology. We analysed whole genome sequence (WGS) data from 119 Neisseria spp. isolates from a surveillance programme for oropharyngeal Neisseria spp. in Belgium. Different species identification methods were compared: (i) MALDI-TOF MS, (ii) Ribosomal Multilocus Sequence Typing (rMLST) and (iii) rplF gene species identification. WGS data were used to further characterize Neisseria species found with supplementary analyses of Neisseria cinerea genomes.
Results. Based on genomic species identification, isolates from the oropharyngeal Neisseria surveilence study were composed of the following species: N. meningitidis (n=23), N. subflava (n=61), N. mucosa (n=15), N. oralis (n=8), N. cinerea (n=5), N. elongata (n=3), N. lactamica (n=2), N. bacilliformis (n=1) and N. polysaccharea (n=1). Of these 119 isolates, four isolates identified as N. meningitidis (n=3) and N. subflava (n=1) by MALDI-TOF MS, were determined to be N. polysaccharea (n=1), N. cinerea (n=2) and N. mucosa (n=1) by rMLST. Phylogenetic analyses revealed that N. cinerea isolates from the general population (n=3, cluster one) were distinct from those obtained from men who have sex with men (MSM, n=2, cluster two). The latter contained genomes misidentified as N. meningitidis using MALDI-TOF MS. These two N. cinerea clusters persisted after the inclusion of published N. cinerea WGS (n=42). Both N. cinerea clusters were further defined through pangenome and Average Nucleotide Identity (ANI) analyses.
Conclusion. This study provides insights into the importance of genomic genus-wide Neisseria surveillance studies to improve the characterization and identification of the Neisseria genus.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 3
DOI: 10.1099/jmm.0.001871
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“Unlocking Novel Anticancer Strategies: Bioactive Hydrogels for Local Delivery of Plasma‐Derived Oxidants in an In Ovo Cancer Model”. Espona‐Noguera A, Živanić, M, Smits E, Bogaerts A, Privat‐Maldonado A, Canal C, Macromolecular Bioscience (2024). http://doi.org/10.1002/mabi.202400213
Abstract: Cold atmospheric plasma (CAP) is a tool with the ability to generate reactive oxygen and nitrogen species (RONS), which can induce therapeutic effects like disinfection, wound healing, and cancer treatment. In the plasma oncology field, CAP‐treated hydrogels (PTHs) are being explored for the local administration of CAP‐derived RONS as a novel anticancer approach. PTHs have shown anticancer effects in vitro, however, they have not yet been studied in more relevant cancer models. In this context, the present study explores for the first time the therapeutic potential of PTHs using an advanced in ovo cancer model. PTHs composed of alginate (Alg), gelatin (Gel), Alg/Gel combination, or Alg/hyaluronic acid (HA) combination are investigated. All embryos survived the PTHs treatment, suggesting that the in ovo model could become a time‐ and cost‐effective tool for developing hydrogel‐based anticancer approaches. Results revealed a notable reduction in CD44+ cell population and their proliferative state for the CAP‐treated Alg‐HA condition. Moreover, the CAP‐treated Alg‐HA formulation alters the extracellular matrix composition, which may help combat drug‐resistance. In conclusion, the present study validates the utility of in ovo cancer model for PTHs exploration and highlights the promising potential of Alg‐based PTHs containing HA and CAP‐derived RONS for cancer treatment.
Keywords: A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 4.6
DOI: 10.1002/mabi.202400213
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“Sorption-Enhanced Dry Reforming of Methane in a DBD Plasma Reactor for Single-Stage Carbon Capture and Utilization”. Vertongen R, De Felice G, van den Bogaard H, Gallucci F, Bogaerts A, Li S, ACS Sustainable Chemistry &, Engineering 12, 10841 (2024). http://doi.org/10.1021/acssuschemeng.4c02502
Abstract: Plasma−sorbent systems are a novel technology for single-stage carbon capture and utilization (CCU), where the plasma enables the desorption of CO2 from a sorbent and the simultaneous conversion to CO. In this study, we test the flexibility of a plasma−sorbent system in a single unit, specifically for sorption-enhanced dry reforming of methane (DRM). The experimental results indicate the selective adsorption of CO2 by the sorbent zeolite 5A in the first step, and CH4 addition during the plasma-based desorption of CO2 enables DRM to various value-added products in the second step, such as H2, CO, hydrocarbons, and the byproduct H2O. Furthermore, our work also demonstrates that zeolite has the potential to increase the conversion of CO2 and CH4, attributed to its capability to capture H2O. Aside from the notable carbon deposition, material analysis shows that the zeolite remains relatively stable under plasma exposure.
Keywords: A1 Journal Article; plasma, dry reforming of methane, dielectric barrier discharge, sorbent, carbon capture and utilization, zeolite; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 8.4
DOI: 10.1021/acssuschemeng.4c02502
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“Can post-plasma CH4injection improve plasma-based dry reforming of methane? A modeling study”. Albrechts M, Tsonev I, Bogaerts A, Green Chemistry 26, 9712 (2024). http://doi.org/10.1039/D4GC02889A
Abstract: Thermal plasma-driven dry reforming of methane (DRM) has gained increased attention in recent years due to its high conversion and energy conversion efficiency (ECE). Recent experimental work investigated the performance of a pure CO<sub>2</sub>plasma with post-plasma CH<sub>4</sub>injection. The rationale behind this strategy is that by utilizing a pure CO<sub>2</sub>plasma, all plasma energy can be used to dissociate CO<sub>2</sub>, while CH<sub>4</sub>reforming proceeds post-plasma in the reforming reactor with residual heat, potentially improving the energy efficiency compared to injecting both CO<sub>2</sub>and CH<sub>4</sub>into the plasma. To assess whether post-plasma CH<sub>4</sub>injection indeed improves the DRM performance, we developed a chemical kinetics model describing the post-plasma conversion process. We first validated our model by reproducing the experimental results of the pure CO<sub>2</sub>plasma with post-plasma CH<sub>4</sub>injection. Subsequently, we compared both strategies: injecting only CO<sub>2</sub>inside the plasma while injecting CH<sub>4</sub>post-plasma,<italic>vs.</italic>classical plasma-based DRM. Our modeling results indicate that below specific energy inputs (SEI) of 220 kJ mol<sup>−1</sup>, the total conversion slightly improves (<italic>ca.</italic>5%) with the first strategy. However, the ECE is slightly lower due to the low H<sub>2</sub>selectivity caused by substantial H<sub>2</sub>O formation. The highest conversion and ECE are obtained at SEI values of 240–280 kJ mol<sup>−1</sup>, where both strategies yield nearly identical results, indicating the limited potential of improving the performance of DRM by pure CO<sub>2</sub>plasma with post-plasma CH<sub>4</sub>injection. Nevertheless, the approach is still very valuable to allow higher CH<sub>4</sub>/CO<sub>2</sub>ratios without problems of coke formation within the plasma, and thus, to improve plasma stability and reach higher syngas ratios, which is more useful for further Fischer–Tropsch or methanol synthesis.
Keywords: A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 9.8
DOI: 10.1039/D4GC02889A
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“Plasma-catalytic dry reforming of CH4: Effects of plasma-generated species on the surface chemistry”. Sun J, Chen Q, Qin W, Wu H, Liu B, Li S, Bogaerts A, Chemical Engineering Journal 498, 155847 (2024). http://doi.org/10.1016/j.cej.2024.155847
Abstract: By means of steady-state experiments and a global model, we studied the effects of plasma-generated reactive species on the surface chemistry and coking in plasma-catalytic CH4/CO2 reforming at reduced pressure (8–40 kPa). We used a hybrid ZDPlasKin-CHEMKIN model to predict the species densities over time. The detailed plasma-catalytic mechanism consists of the plasma discharge scheme, a gas-phase chemistry set and a surface mechanism. Our experimental results show that the coupling of Ni/SiO2 catalyst with plasma is more effective in CH4/CO2 activation and conversion than unpacked DBD plasma, with syngas being the main products. The
highest total conversion of 16 % was achieved at 8000 V and 473 K, with corresponding CO and H2 yields of 15 % and 12 %, respectively. The reactants conversion and product selectivity are well captured by the kinetic model. Our simulation results suggest that vibrational species and radicals can accelerate the dissociative adsorption and Eley-Rideal (E-R) reactions. Path flux analysis shows that E-R reactions dominate the surface reaction pathways, which differs from thermal catalysis, indicating that the coupling of non-equilibrium plasma and catalysis can effectively shift the formation and consumption pathways of important adsorbates. For instance, our model suggests that HCOO(s) is primarily generated through the E-R reaction CO2(v) + H(s) → HCOO(s), while the hydrogenation reaction HCOO(s) + H → HCOOH(s) is the main source of HCOOH(s). Carbon deposition on the
catalyst surface is primarily formed through the stepwise dehydrogenation of CH4, while the E-R reactions enhanced by plasma-generated H and O atoms dominate the consumption of carbon deposition. This work provides new insights into the effects of reactive species on the surface chemistry in plasma-catalytic CH4/CO2 reforming.
Keywords: A1 Journal Article; Dry reforming of methane Plasma catalysis Plasma-enhanced surface chemistry Path flux and sensitivity analysis Coking kinetics; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 15.1
DOI: 10.1016/j.cej.2024.155847
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“Plasma-assisted NH3 cracking in warm plasma reactors for green H2 production”. Fedirchyk I, Tsonev I, Quiroz Marnef R, Bogaerts A, Chemical Engineering Journal 499, 155946 (2024). http://doi.org/10.1016/j.cej.2024.155946
Abstract: renewable energy. Plasma technology is promising for this purpose, as it can crack NH3 without the need for a catalyst and is highly compatible with renewable electricity, reducing the environmental footprint of the cracking process. This work investigates the NH3 cracking performance of four different warm plasma reactors with different configurations and operating in a wide range of conditions. We show that the NH3 conversion in warm plasma reactors is primarily determined by the specific energy input, with the main difference observed in the energy cost (EC) of cracking. The lowest EC obtained is 146 kJ/mol but at a conversion of only 8 %. A more reasonable conversion of around 50 % yields an EC of around 200 kJ/mol in two of the reactors investigated. Plasma reactors operating at higher feed flow rates are more efficient and yield a higher H2 production rate. Our data indicate that NH3 cracking in these warm plasma reactors occurs mainly via thermal chemistry, with nonthermal plasma chemistry playing a less prominent role. NH3 decomposes not only inside the plasma core but also in a hot volume around it, which reduces the EC. Our study shows that warm plasmas are significantly more efficient for NH3 cracking than cold plasmas, even when the latter are combined with catalysts.
Keywords: A1 Journal Article; Plasma-assisted NH3 cracking Plasma reactors Warm plasma H2 production from NH3; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 15.1
DOI: 10.1016/j.cej.2024.155946
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“The effect of the acceleration voltage on the quality of structure determination by 3D-electron diffraction”. Gholam S, Hadermann J, Ultramicroscopy 266, 114022 (2024). http://doi.org/10.1016/j.ultramic.2024.114022
Abstract: Nowadays, 3D Electron Diffraction (3DED) is widely used for the structure determination of sub-micron-sized particles. In this work, we investigate the influence of the acceleration voltage on the quality of 3DED datasets acquired on BaTiO3 nanoparticles. Datasets were acquired using a wide range of beam energies, from common, high acceleration voltages (300 kV and 200 kV) to medium (120 kV and 80 kV) and low acceleration voltages (60 kV and 30 kV). In the integration process, Rint increases as the beam energy reduces, which is mainly due to the increased dynamical scattering. Nevertheless, the structure was solved successfully in all cases. The structure refinement was comparable for all beam energies with small deficiencies such as negative atomic displacements for the heaviest atom in the structure, barium. Including extinction correction in the refinement noticeably improved the model for low acceleration voltages, probably due to higher beam absorption in these cases. Dynamical refinement, however, shows superior results for higher acceleration voltages, since the dynamical refinement calculations currently discard inelastic scattering effects.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 2.2
DOI: 10.1016/j.ultramic.2024.114022
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“Obtaining 3D Atomic Reconstructions from Electron Microscopy Images Using a Bayesian Genetic Algorithm: Possibilities, Insights, and Limitations”. Stoops T, De Backer A, Lobato I, Van Aert S, Microscopy and Microanalysis (2024). http://doi.org/10.1093/mam/ozae090
Abstract: The Bayesian genetic algorithm (BGA) is a powerful tool to reconstruct the 3D structure of mono-atomic single-crystalline metallic nanoparticles imaged using annular dark field scanning transmission electron microscopy. The number of atoms in a projected atomic column in the image is used as input to obtain an accurate and atomically precise reconstruction of the nanoparticle, taking prior knowledge and the finite precision of atom counting into account. However, as the number of parameters required to describe a nanoparticle with atomic detail rises quickly with the size of the studied particle, the computational costs of the BGA rise to prohibitively expensive levels. In this study, we investigate these computational costs and propose methods and control parameters for efficient application of the algorithm to nanoparticles of at least up to 10 nm in size.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 2.8
DOI: 10.1093/mam/ozae090
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“Optimization of three-dimensional electron diffuse scattering data acquisition”. Poppe R, Hadermann J, Ultramicroscopy 265, 114023 (2024). http://doi.org/10.1016/j.ultramic.2024.114023
Abstract: The diffraction patterns of crystalline materials with local order contain sharp Bragg reflections as well as highly structured diffuse scattering. In this study, we quantitatively show how the diffuse scattering in three-dimensional electron diffraction (3D ED) data is influenced by various parameters, including the data acquisition mode, the detector type and the use of an energy filter. We found that diffuse scattering data used for quantitative analysis are preferably acquired in selected area electron diffraction (SAED) mode using a CCD and an energy filter. In this study, we also show that the diffuse scattering in 3D ED data can be obtained with a quality comparable to that from single-crystal X-ray diffraction. As electron diffraction requires much smaller crystal sizes than X-ray diffraction, this opens up the possibility to investigate the local structure of many technologically relevant materials for which no crystals large enough for single-crystal X-ray diffraction are available.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 2.2
DOI: 10.1016/j.ultramic.2024.114023
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