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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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“Mechanism of Nitrogen Fixation by Nitrogenase: The Next Stage”. Hoffman BM, Lukoyanov D, Yang Z-Y, Dean DR, Seefeldt LC, Chemical Reviews 114, 4041 (2014). http://doi.org/10.1021/cr400641x
Abstract: Ammonia is a crucial nutrient used for plant growth and as a building block in pharmaceutical and chemical industry, produced via nitrogen fixation of the ubiquitous atmospheric N2. Current industrial ammonia production relies heavily on fossil resources, but a lot of work is put into developing non-fossil based pathways. Among these is the use of nonequilibrium plasma. In this work, we investigated water vapor as H source for nitrogen fixation into NH3 by non-equilibrium plasma. The highest selectivity towards NH3 was observed with low amounts of added H2O vapor, but the highest production rate was reached at high H2O vapor.
Keywords: A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
DOI: 10.1021/cr400641x
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“DFT Study of Synergistic Catalysis of the Water-Gas-Shift Reaction on Cu-Au Bimetallic Surfaces”. Saqlain MA, Hussain A, Siddiq DM, Leenaerts O, Leitão AA, ChemCatChem 8, 1208 (2016). http://doi.org/10.1002/cctc.201501312
Abstract: The water-gas-shift reaction (WGSR) is an important industrial process that can be significantly enhanced at suitable catalyst surfaces. In this work, we investigate the catalytic behavior of metallic Cu(1 0 0) and bimetallic Cu–Au(1 0 0) surfaces. With density functional theory calculations, the variation in the Gibbs free energy (ΔG°), the activation barriers, and the rate constants for the WGSR are calculated. The variation in ΔG° for water dissociation shows that the process is spontaneous up to 520 K on the bimetallic surface and up to 229 K on the Cu(1 0 0) surface. The calculated rate constants for the process also show that the bimetallic surface is much more reactive than the Cu(1 0 0) surface. The calculated pressure–temperature phase diagram for water dissociation shows that the partial pressure of H2O required for water dissociation on the bimetallic surface is substantially lower than that on the Cu(1 0 0) surface at all the studied temperatures. Additionally, the calculations demonstrate that the kinetics of the water-gas-shift reaction is dominated by redox processes on both the surfaces.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.803
Times cited: 8
DOI: 10.1002/cctc.201501312
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“An eco-friendly soft template synthesis of mesostructured silica-carbon nanocomposites for acid catalysis”. Zhong R, Peng L, de Clippel F, Gommes C, Goderis B, Ke X, Van Tendeloo G, Jacobs PA, Sels BF, ChemCatChem 7, 3047 (2015). http://doi.org/10.1002/cctc.201500728
Abstract: The synthesis of ordered mesoporous silica-carbon composites was explored by employing TEOS and sucrose as the silica and carbon precursor respectively, and the triblock copolymer F127 as a structure-directing agent via an evaporation-induced self-assembly (EISA) process. It is demonstrated that the synthesis procedures allow for control of the textural properties and final composition of these silica-carbon nanocomposites via adjustment of the effective SiO2/C weight ratio. Characterization by SAXS, N-2 physisorption, HRTEM, TGA, and C-13 and Si-29 solid-state MAS NMR show a 2D hexagonal mesostructure with uniform large pore size ranging from 5.2 to 7.6nm, comprising of separate carbon phases in a continuous silica phase. Ordered mesoporous silica and non-ordered porous carbon can be obtained by combustion of the pyrolyzed nanocomposites in air or etching with HF solution, respectively. Sulfonic acid groups can be readily introduced to such kind of silica-carbon nanocomposites by a standard sulfonation procedure with concentrated sulfuric acid. Excellent acid-catalytic activities and selectivities for the dimerization of styrene to produce 1,3-diphenyl-1-butene and dimerization of -methylstyrene to unsaturated dimers were demonstrated with the sulfonated materials.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.803
Times cited: 13
DOI: 10.1002/cctc.201500728
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“Dual improvement of beta-MnO₂, oxygen evolution electrocatalysts via combined substrate control and surface engineering”. Bigiani L, Gasparotto A, Maccato C, Sada C, Verbeeck J, Andreu T, Morante JR, Barreca D, Chemcatchem , 1 (2020). http://doi.org/10.1002/CCTC.202000999
Abstract: The development of catalysts with high intrinsic activity towards the oxygen evolution reaction (OER) plays a critical role in sustainable energy conversion and storage. Herein, we report on the development of efficient (photo)electrocatalysts based on functionalized MnO(2)systems. Specifically,beta-MnO(2)nanostructures grown by plasma enhanced-chemical vapor deposition on fluorine-doped tin oxide (FTO) or Ni foams were decorated with Co(3)O(4)or Fe(2)O(3)nanoparticles by radio frequency sputtering. Upon functionalization, FTO-supported materials yielded a performance increase with respect to bare MnO2, with current densities at 1.65 Vvs. the reversible hydrogen electrode (RHE) up to 3.0 and 3.5 mA/cm(2)in the dark and under simulated sunlight, respectively. On the other hand, the use of highly porous and conductive Ni foam substrates enabled to maximize cooperative interfacial effects between catalyst components. The best performing Fe2O3/MnO(2)system provided a current density of 17.9 mA/cm(2)at 1.65 Vvs. RHE, an overpotential as low as 390 mV, and a Tafel slope of 69 mV/decade under dark conditions, comparing favorably with IrO(2)and RuO(2)benchmarks. Overall, the control of beta-MnO2/substrate interactions and the simultaneous surface property engineering pave the way to an efficient energy generation from abundant natural resources.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.5
Times cited: 5
DOI: 10.1002/CCTC.202000999
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“Pd/Lewis acid synergy in macroporous Pd@Na-ZSM-5 for enhancing selective conversion of biomass”. Liu J-W, Wu S-M, Wang L-Y, Tian G, Qin Y, Wu J-X, Zhao X-F, Zhang Y-X, Chang G-G, Wu L, Zhang Y-X, Li Z-F, Guo C-Y, Janiak C, Lenaerts S, Yang X-Y, Chemcatchem , 1 (2020). http://doi.org/10.1002/CCTC.202000868
Abstract: Pd nanometal particles encapsulated in macroporous Na-ZSM-5 with only Lewis acid sites have been successfully synthesized by a steam-thermal approach. The synergistic effect of Pd and Lewis acid sites have been investigated for significant enhancement of the catalytic selectivity towards furfural alcohol in furfural hydroconversion.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.5
Times cited: 1
DOI: 10.1002/CCTC.202000868
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“Waste-derived copper-lead electrocatalysts for CO₂, reduction”. Yang S, An H, Anastasiadou D, Xu W, Wu L, Wang H, de Ruiter J, Arnouts S, Figueiredo MC, Bals S, Altantzis T, van der Stam W, Weckhuysen BM, ChemCatChem 14, e202200754 (2022). http://doi.org/10.1002/CCTC.202200754
Abstract: It remains a real challenge to control the selectivity of the electrocatalytic CO2 reduction (eCO(2)R) reaction to valuable chemicals and fuels. Most of the electrocatalysts are made of non-renewable metal resources, which hampers their large-scale implementation. Here, we report the preparation of bimetallic copper-lead (CuPb) electrocatalysts from industrial metallurgical waste. The metal ions were extracted from the metallurgical waste through simple chemical treatment with ammonium chloride, and CuxPby electrocatalysts with tunable compositions were fabricated through electrodeposition at varying cathodic potentials. X-ray spectroscopy techniques showed that the pristine electrocatalysts consist of Cu-0, Cu1+ and Pb2+ domains, and no evidence for alloy formation was found. We found a volcano-shape relationship between eCO(2)R selectivity toward two electron products, such as CO, and the elemental ratio of Cu and Pb. A maximum Faradaic efficiency towards CO was found for Cu9.00Pb1.00, which was four times higher than that of pure Cu, under the same electrocatalytic conditions. In situ Raman spectroscopy revealed that the optimal amount of Pb effectively improved the reducibility of the pristine Cu1+ and Pb2+ domains to metallic Cu and Pb, which boosted the selectivity towards CO by synergistic effects. This work provides a framework of thinking to design and tune the selectivity of bimetallic electrocatalysts for CO2 reduction through valorization of metallurgical waste.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 4.5
Times cited: 7
DOI: 10.1002/CCTC.202200754
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“Study of hydrogen peroxide reactions on manganese oxides as a tool to decode the oxygen reduction reaction mechanism”. Ryabova AS, Bonnefont A, Zagrebin P, Poux T, Sena RP, Hadermann J, Abakumov AM, Kerangueven G, Istomin SY, Antipov EV, Tsirlina GA, Savinova ER, ChemElectroChem 3, 1667 (2016). http://doi.org/10.1002/CELC.201600236
Abstract: Hydrogen peroxide has been detected as a reaction intermediate in the electrochemical oxygen reduction reaction (ORR) on transition-metal oxides and other electrode materials. In this work, we studied the electrocatalytic and catalytic reactions of hydrogen peroxide on a set of Mn oxides, Mn2O3, MnOOH, LaMnO3, MnO2, and Mn3O4, that adopt different crystal structures to shed light on the mechanism of the ORR on these materials. We then combined experiment with kinetic modeling with the objective to correlate the differences in the ORR activity to the kinetics of the elementary reaction steps, and we uncovered the importance of structural and compositional factors in the catalytic activity of the Mn oxides. We concluded that the exceptional activity of Mn2O3 in the ORR is due to its high catalytic activity both in the reduction of oxygen to hydrogen peroxide and in the decomposition of the latter, and furthermore, we proposed a tentative link between crystal structure and reactivity.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.136
Times cited: 20
DOI: 10.1002/CELC.201600236
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“Attaching redox proteins onto electrode surfaces by bis-silane”. Trashin S, De Jong M, Meynen V, Dewilde S, De Wael K, ChemElectroChem 3, 1035 (2016). http://doi.org/10.1002/CELC.201600021
Abstract: Immobilization of redox proteins on electrode surfaces is of special interest for mechanistic studies and applications because of a well-controlled redox state of protein molecules by a polarized electrode and fast electron transfer kinetics, free from diffusion limitation. Here, bis-organosilane (1,2-bis(trimethoxysilyl)ethane) was applied as a fresh solution in a pH 7 phosphate buffer without use of any organic solvent, sol-gel or mesoporous bulk matrix. A short aging period of 30 minutes before deposition on the electrodes was optimal for the immobilization of proteins. Three redox proteins (cytochrome c, neuroglobin and GLB-12) were confined to the gold surface of electrodes with high coverages and stability, indicating that the suggested technique is simple, efficient and generic in nature.
Keywords: A1 Journal article; Laboratory of adsorption and catalysis (LADCA); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 4.136
Times cited: 4
DOI: 10.1002/CELC.201600021
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“Electrocatalytic oxidation of water by OH- –, and H₂O-capped IrOx nanoparticles electrophoretically deposited on graphite and basal plane HOPG : effect of the substrate electrode”. Mirbagheri N, Campos R, Ferapontova EE, Chemelectrochem 8, 1632 (2021). http://doi.org/10.1002/CELC.202100317
Abstract: Iridium oxide (IrOx) is one of the most efficient electrocatalysts for water oxidation reaction (WOR). Here, WOR electrocatalysis by 1.6 nm IrOx nanoparticles (NPs) electrophoretically deposited onto spectroscopic graphite (Gr) and basal plane highly ordered pyrolytic graphite (HOPG) was studied as a function of NPs' capping ligands and electrodeposition substrate. On Gr, OH-- and H2O-capped NPs exhibited close sub-monolayer surface coverages and specific electrocatalytic activity of 18.9-23.5 mA nmol(-1) of Ir-IV/V sites, at 1 V and pH 7. On HOPG, OH--capped NPs produced films with a diminished WOR activity of 5.17 +/- 2.40 mA nmol(-1). Electro-wettability-induced changes impeded electrophoretic deposition of H2O-capped NPs on HOPG, WOR currents being 25-fold lower than observed for OH--capped ones. The electrocatalysis efficiency correlated with hydrophilic properties of the substrate electrodes, affecting morphological and as a result catalytic properties of the formed IrOx films. These results, important both for studied and related carbon nanomaterials systems, allow fine-tuning of electrocatalysis by a proper choice of the substrate electrode.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 4.136
DOI: 10.1002/CELC.202100317
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“Towards developing a screening strategy for ecstasy : revealing the electrochemical profile”. Thiruvottriyur Shanmugam S, Van Echelpoel R, Boeye G, Eliaerts J, Samanipour M, Ching HYV, Florea A, Van Doorslaer S, Van Durme F, Samyn N, Parrilla M, De Wael K, Chemelectrochem 8, 4826 (2021). http://doi.org/10.1002/CELC.202101198
Abstract: This article describes the development of an electrochemical screening strategy for 3,4-methylenedioxymethamphetamine (MDMA), the regular psychoactive compound in ecstasy (XTC) pills. We have investigated the specific electrochemical profile of MDMA and its electro-oxidation mechanisms at disposable graphite screen-printed electrodes. We have proved that the formation of a radical cation and subsequent reactions are indeed responsible for the electrode surface passivation, as evidenced by using electron paramagnetic resonance spectroscopy and electrochemistry. Thereafter, pure cutting agents and MDMA as well as simulated binary mixtures of compounds with MDMA were subjected to square wave voltammetry at pH 7 to understand the characteristic electrochemical profile. An additional measurement at pH 12 was able to resolve false positives and negatives occurring at pH 7. Finally, validation of the screening strategy was done by measuring a set of ecstasy street samples. Overall, our proposed electrochemical screening strategy has been demonstrated for the rapid, sensitive, and selective detection of MDMA, resolving most of the false positives and negatives given by the traditional Marquis color tests, thus exhibiting remarkable promises for the on-site screening of MDMA.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Organic synthesis (ORSY); Applied Electrochemistry & Catalysis (ELCAT); Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
Impact Factor: 4.136
DOI: 10.1002/CELC.202101198
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“Inhibiting recombination to improve the performance of plasma-based CO2 conversion”. Wang K, Ceulemans S, Zhang H, Tsonev I, Zhang Y, Long Y, Fang M, Li X, Yan J, Bogaerts A, Chemical Engineering Journal 481, 148684 (2024). http://doi.org/10.1016/j.cej.2024.148684
Abstract: Warm plasma offers a promising route for CO2 splitting into valuable CO, yet recombination reactions of CO with oxygen, forming again CO2, have recently emerged as critical limitation. This study combines experiments and fluid dynamics + chemical kinetics modelling to comprehensively analyse the recombination reactions upon CO2 splitting in an atmospheric plasmatron. We introduce an innovative in-situ gas sampling technique, enabling 2D spatial mapping of gas product compositions and temperatures, experimentally confirming for the first time the substantial limiting effect of CO recombination reactions in the afterglow region. Our results show that the CO mole fraction at a 5 L/min flow rate drops significantly from 11.9 % at a vertical distance of z = 20 mm in the afterglow region to 8.6 % at z = 40 mm. We constructed a comprehensive 2D model that allows for spatial reaction rates analysis incorporating crucial reactions, and we validated it to kinetically elucidate this phenomenon. CO2 +M⇌O+CO+M and CO2 +O⇌CO+O2 are the dominant reactions, with the forward reactions prevailing in the plasma region and the backward reactions becoming prominent in the afterglow region. These results allow us to propose an afterglow quenching strategy for performance enhancement, which is further demonstrated through a meticulously developed plasmatron reactor with two-stage cooling. Our approach substantially increases the CO2 conversion (e.g., from 6.6 % to 19.5 % at 3 L/min flow rate) and energy efficiency (from 13.5 % to 28.5 %, again at 3 L/min) and significantly shortens the startup time (from ~ 150 s to 25 s). Our study underscores the critical role of inhibiting recombination reactions in plasma-based CO2 conversion and offers new avenues for performance enhancement.
Keywords: A1 Journal Article; Plasma-based CO2 splitting Recombination reactions In-situ gas sampling Fluid dynamics modeling Kinetics modeling Afterglow quenching; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 15.1
DOI: 10.1016/j.cej.2024.148684
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“Importance of plasma discharge characteristics in plasma catalysis: Dry reforming of methane vs. ammonia synthesis”. De Meyer R, Gorbanev Y, Ciocarlan R-G, Cool P, Bals S, Bogaerts A, Chemical engineering journal 488, 150838 (2024). http://doi.org/10.1016/j.cej.2024.150838
Abstract: Plasma catalysis is a rapidly growing field, often employing a packed-bed dielectric barrier discharge plasma reactor. Such dielectric barrier discharges are complex, especially when a packing material (e.g., a catalyst) is introduced in the discharge volume. Catalysts are known to affect the plasma discharge, though the underlying mechanisms influencing the plasma physics are not fully understood. Moreover, the effect of the catalysts on the plasma discharge and its subsequent effect on the overall performance is often overlooked. In this work, we deliberately design and synthesize catalysts to affect the plasma discharge in different ways. These Ni or Co alumina-based catalysts are used in plasma-catalytic dry reforming of methane and ammonia synthesis. Our work shows that introducing a metal to the dielectric packing can affect the plasma discharge, and that the distribution of the metal is crucial in this regard. Further, the altered discharge can greatly influence the overall performance. In an atmospheric pressure dielectric barrier discharge reactor, this apparently more uniform plasma yields a significantly better performance for ammonia synthesis compared to the more conventional filamentary discharge, while it underperforms in dry reforming of methane. This study stresses the importance of analyzing the plasma discharge in plasma catalysis experiments. We hope this work encourages a more critical view on the plasma discharge characteristics when studying various catalysts in a plasma reactor.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 15.1
DOI: 10.1016/j.cej.2024.150838
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“Coupled multi-dimensional modelling of warm plasmas: Application and validation for an atmospheric pressure glow discharge in CO2/CH4/O2”. Maerivoet S, Tsonev I, Slaets J, Reniers F, Bogaerts A, Chemical Engineering Journal 492, 152006 (2024). http://doi.org/10.1016/j.cej.2024.152006
Abstract: To support experimental research into gas conversion by warm plasmas, models should be developed to explain the experimental observations. These models need to describe all physical and chemical plasma properties in a coupled way. In this paper, we present a modelling approach to solve the complete set of assumed relevant equations, including gas flow, heat balance and species transport, coupled with a rather extensive chemistry set, consisting of 21 species, obtained by reduction of a more detailed chemistry set, consisting of 41 species. We apply this model to study the combined CO2 and CH4 conversion in the presence of O2, in a direct current atmospheric pressure glow discharge. Our model can predict the experimental trends, and can explain why higher O2 fractions result in higher CH4 conversion, namely due to the higher gas temperature, rather than just by additional chemical reactions. Indeed, our model predicts that when more O2 is added, the energy required to reach any set temperature (i.e., the enthalpy) drops, allowing the system to reach higher temperatures with similar amounts of energy. This is in turn related to the higher H2O fraction and lower H2 fraction formed in the plasma, as demonstrated by our model. Altogether, our new self-consistent model can capture the main physics and chemistry occurring in this warm plasma, which is an important step towards predictive modelling for plasma-based gas conversion.
Keywords: A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 15.1
DOI: 10.1016/j.cej.2024.152006
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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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“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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“NH3 decomposition for H2 production by thermal and plasma catalysis using bimetallic catalysts”. Meng S, Li S, Sun S, Bogaerts A, Liu Y, Yi Y, Chemical engineering science 283, 119449 (2024). http://doi.org/10.1016/j.ces.2023.119449
Abstract: Plasma catalysis has emerged as a promising approach for driving thermodynamically unfavorable chemical
reactions. Nevertheless, comprehending the mechanisms involved remains a challenge, leading to uncertainty
about whether the optimal catalyst in plasma catalysis aligns with that in thermal catalysis. In this research, we
explore this question by studying monometallic catalysts (Fe, Co, Ni and Mo) and bimetallic catalysts (Fe-Co, Mo-
Co, Fe-Ni and Mo-Ni) in both thermal catalytic and plasma catalytic NH3 decomposition. Our findings reveal that
the Fe-Co bimetallic catalyst exhibits the highest activity in thermal catalysis, the Fe-Ni bimetallic catalyst
outperforms others in plasma catalysis, indicating a discrepancy between the optimal catalysts for the two
catalytic modes in NH3 decomposition. Comprehensive catalyst characterization, kinetic analysis, temperature
program surface reaction experiments and plasma diagnosis are employed to discuss the key factors influencing
NH3 decomposition performance.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.7
DOI: 10.1016/j.ces.2023.119449
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“Facile morphology-controlled synthesis of organolead iodide perovskite nanocrystals using binary capping agents”. Debroye E, Yuan H, Bladt E, Baekelant W, Van der Auweraer M, Hofkens J, Bals S, Roeffaers MBJ, ChemNanoMat : chemistry of nanomaterials for energy, biology and more 3, 223 (2017). http://doi.org/10.1002/CNMA.201700006
Abstract: Controlling the morphology of organolead halide perovskite crystals is crucial to a fundamental understanding of the materials and to tune their properties for device applications. Here, we report a facile solution-based method for morphology-controlled synthesis of rod-like and plate-like organolead halide perovskite nanocrystals using binary capping agents. The morphology control is likely due to an interplay between surface binding kinetics of the two capping agents at different crystal facets. By high-resolution scanning transmission electron microscopy, we show that the obtained nanocrystals are monocrystalline. Moreover, long photoluminescence decay times of the nanocrystals indicate long charge diffusion lengths and low trap/defect densities. Our results pave the way for large-scale solution synthesis of organolead halide perovskite nanocrystals with controlled morphology for future device applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.937
Times cited: 19
DOI: 10.1002/CNMA.201700006
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“Tunable nitrogen-doped carbon nanoparticles from tannic acid and urea and their potential for sustainable soots”. Berthold T, Castro CR, Winter M, Hoerpel G, Kurttepeli M, Bals S, Antonietti M, Fechler N, ChemNanoMat : chemistry of nanomaterials for energy, biology and more 3, 311 (2017). http://doi.org/10.1002/CNMA.201700051
Abstract: Nano-sized nitrogen-doped carbon spheres are synthesized from two cheap, readily available and sustainable precursors: tannic acid and urea. In combination with a polymer structuring agent, nitrogen content, sphere size and the surface (up to 400 m(2)g(-1)) can be conveniently tuned by the precursor ratio, temperature and structuring agent content. Because the chosen precursors allow simple oven synthesis and avoid harsh conditions, this carbon nanosphere platform offers a more sustainable alternative to classical soots, for example, as printing pigments or conduction soots. The carbon spheres are demonstrated to be a promising as conductive carbon additive in anode materials for lithium ion batteries.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.937
Times cited: 14
DOI: 10.1002/CNMA.201700051
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“Leaf-deposited semi-volatile organic compounds (SVOCs) : an exploratory study using GCxGC-TOFMS on leaf washing solutions”. Castanheiro A, Joos P, Wuyts K, De Wael K, Samson R, Chemosphere 214, 103 (2019). http://doi.org/10.1016/J.CHEMOSPHERE.2018.09.067
Abstract: Airborne particulate matter (PM) includes semi-volatile organic compounds (SVOCs), which can be deposited on vegetation matrices such as plant leaves. In alternative to air-point measurements or artificial passive substrates, leaf monitoring offers a cost-effective, time-integrating means of assessing local air quality. In this study, leaf washing solutions from ivy (Hedera hibernica) leaves exposed during one-month at different land use classes were explored via comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-TOFMS). The composition of leaf-deposited SVOCs, corrected for those of unexposed leaves, was compared against routinely monitored pollutants concentrations (PM10, PM2.5, O3, NO2, SO2) measured at co-located air monitoring stations. The first study on leaf-deposited SVOCs retrieved from washing solutions, herein reported, delivered a total of 911 detected compounds. While no significant land use (rural, urban, industrial, traffic, mixed) effects were observed, increasing exposure time (from one to 28 days) resulted in a higher number and diversity of SVOCs, suggesting cumulative time-integration to be more relevant than local source variations between sites. After one day, leaf-deposited SVOCs were mainly due to alcohols, N-containing compounds, carboxylic acids, esters and lactones, while ketones, diketones and hydrocarbons compounds gained relevance after one week, and phenol compounds after one month. As leaf-deposited SVOCs became overall more oxidized throughout exposure time, SVOCs transformation or degradation at the leaf surface is suggested to be an important phenomenon. This study confirmed the applicability of GCxGC-TOFMS to analyze SVOCs from leaf washing solutions, further research should include validation of the methodology and comparison with atmospheric organic pollutants.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 4.208
DOI: 10.1016/J.CHEMOSPHERE.2018.09.067
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“Precision and accuracy of ST-EDXRF performance for As determination comparing with ICP-MS and evaluation of As deviation in the soil media”. Akbulut S, Cevik U, Van AA, De Wael K, Van Grieken R, Chemosphere 96, 16 (2014). http://doi.org/10.1016/J.CHEMOSPHERE.2013.06.086
Abstract: The present study was conducted to (i) determine the precision and accuracy of arsenic measurement in soil samples using ST-EDXRF by comparison with the results of ICP-MS analyses and (ii) identify the relationship of As concentration with soil characteristics. For the analysis of samples, inductively coupled plasma mass spectrometry (ICP-MS) and energy dispersive X-ray fluorescence spectrometry (EDXRF) were performed. According to the results found in the soil samples, the addition of HCl to HNO3, used for the digestion gave significant variations in the recovery of As. However, spectral interferences between peaks for As and Pb can affect detection limits and accuracy for XRF analysis. When comparing the XRF and ICP-MS results a correlation was observed with R2 = 0.8414. This means that using a ST-EDXRF spectrometer, it is possible to achieve accurate and precise analysis by the calibration of certified reference materials and choosing an appropriate secondary target. On the other hand, with regard to soil characteristics analyses, the study highlighted that As is mostly anthropogenically enriched in the studied area.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 4.208
Times cited: 5
DOI: 10.1016/J.CHEMOSPHERE.2013.06.086
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“Catalytic Nox reduction with simultaneous dioxin and furan oxidation”. Goemans M, Clarysse P, Joannès J, de Clercq P, Lenaerts S, Matthys K, Boels K, Chemosphere 54, 1357 (2004). http://doi.org/10.1016/S0045-6535(03)00255-8
Abstract: The engineering, construction, performance and running costs of a catalytic flue gas cleaning component in the low dust area of a municipal waste incinerator is discussed. For this purpose, the case study of a Flemish incineration plant is presented, covering the history, the design procedure of the catalyst, relevant process data and the financial aspects. A reliable PCDD/F-destruction by means of oxidation by the catalyst to typical values of 0.001 ng TEQ/Nm3 has been demonstrated. At the same time, NOx− and CO-emissions are reduced by 90% and 20% to about 50 mg/Nm3 and below 10 mg/Nm3, respectively.
Keywords: A1 Journal article
Impact Factor: 4.208
DOI: 10.1016/S0045-6535(03)00255-8
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“Catalytic Nox reduction with simultaneous dioxin and furan oxidation”. Goemans M, Clarysse P, Joannès J, de Clercq P, Lenaerts S, Matthys K, Boels K, Chemosphere 50, 489 (2003). http://doi.org/10.1016/S0045-6535(02)00554-4
Abstract: The engineering, construction, performance and running costs of a catalytic flue gas cleaning component in the low dust area of a municipal waste incinerator is discussed. For this purpose, the case study of a Flemish incineration plant is presented, covering the history, the design procedure of the catalyst, relevant process data and the financial aspects. A reliable PCDD/F-destruction by means of oxidation by the catalyst to typical values of 0.001 ng TEQ/N m3 has been demonstrated. At the same time, NOx- and CO-emissions are reduced by 90% and 20% to about 50 mg/N m3 and below 10 mg/N m3, respectively.
Keywords: A1 Journal article
Impact Factor: 4.208
DOI: 10.1016/S0045-6535(02)00554-4
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“Pioneering on single-sludge nitrification/denitrification at 50 °C”. Vandekerckhove TGL, Boon N, Vlaeminck SE, Chemosphere 252, 126527 (2020). http://doi.org/10.1016/J.CHEMOSPHERE.2020.126527
Abstract: Thermophilic nitrification has been proven in lab-scale bioreactors at 50 °C. The challenge is now to develop a solution for thermophilic nitrogen removal, integrating nitrification with denitrification and aerobic carbon removal. This pioneering study aimed at a single-sludge nitrification/denitrification process at 50 °C, through exposing nitrification in a step by step approach to anoxia and/or organics. Firstly, recurrent anoxia was tolerated by a nitrifying community during long-term membrane bioreactor (MBR) operation (85 days), with high ammonium oxidation efficiencies (>98%). Secondly, five organic carbon sources did not affect thermophilic ammonium and nitrite oxidation rates in three-day aerobic batch flask incubations. Moving to long-term tests with sequencing batch reactors (SBR) and MBR (>250 days), good nitrification performance was obtained at increasing COD/Ninfluent ratios (0, 0.5, 1, 2 and 3). Thirdly, combining nitrification, recurrent anoxia and presence of organic carbon resulted in a nitrogen removal efficiency of 92–100%, with a COD/Nremoved of 4.8 ± 0.6 and a nitrogen removal rate of 50 ± 14 mg N g−1 VSS d−1. Overall, this is the first proof of principle thermophilic nitrifiers can cope with redox fluctuations (aerobic/anoxic) and the aerobic or anoxic presence of organic carbon, can functionally co-exist with heterotrophs and that single-sludge nitrification/denitrification can be achieved.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 8.8
DOI: 10.1016/J.CHEMOSPHERE.2020.126527
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“Enhancing bioflocculation in high-rate activated sludge improves effluent quality yet increases sensitivity to surface overflow rate”. Van Winckel T, Ngo N, Sturm B, Al-Omari A, Wett B, Bott C, Vlaeminck SE, De Clippeleir H, Chemosphere 308, 136294 (2022). http://doi.org/10.1016/J.CHEMOSPHERE.2022.136294
Abstract: High-rate activated sludge (HRAS) relies on good bioflocculation and subsequent solid-liquid separation to maximize the capture of organics. However, full-scale applications often suffer from poor and unpredictable effluent suspended solids (ESS). While the biological aspects of bioflocculation are thoroughly investigated, the effects of fines (settling velocity < 0.6 m3/m2/h), shear and surface overflow rate (SOR) are unclear. This work tackled the impact of fines, shear, and SOR on the ESS in absence of settleable influent solids. This was assessed on a full-scale HRAS step-feed (SF) and pilot-scale HRAS contact-stabilization (CS) configuration using batch settling tests, controlled clarifier experiments, and continuous operation of reactors. Fines contributed up to 25% of the ESS in the full-scale SF configuration. ESS decreased up to 30 mg TSS/L when bioflocculation was enhanced with the CS configuration. The feast-famine regime applied in CS promoted the production of high-quality extracellular polymeric substances (EPS). However, this resulted in a narrow and unfavorable settling velocity distribution, with 50% ± 5% of the sludge mass settling between 0.6 and 1.5 m3/m2/h, thus increasing sensitivity towards SOR changes. A low shear environment (20 s−1) before the clarifier for at least one min was enough to ensure the best possible settling velocity distribution, regardless of prior shear conditions. Overall, this paper provides a more complete view on the drivers of ESS in HRAS systems, creating the foundation for the design of effective HRAS clarifiers. Tangible recommendations are given on how to manage fines and establish the optimal settling velocity of the sludge.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 8.8
DOI: 10.1016/J.CHEMOSPHERE.2022.136294
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“Two-stage anaerobic membrane bioreactor for co-treatment of food waste and kitchen wastewater for biogas production and nutrients recovery”. Le T-S, Nguyen P-D, Ngo HH, Bui X-T, Dang B-T, Diels L, Bui H-H, Nguyen M-T, Le Quang D-T, Chemosphere 309, 136537 (2022). http://doi.org/10.1016/J.CHEMOSPHERE.2022.136537
Abstract: Co-digestion of organic waste and wastewater is receiving increased attention as a plausible waste management approach toward energy recovery. However, traditional anaerobic processes for co-digestion are particularly susceptible to severe organic loading rates (OLRs) under long-term treatment. To enhance technological feasi-bility, this work presented a two-stage Anaerobic Membrane Bioreactor (2 S-AnMBR) composed of a hydrolysis reactor (HR) followed by an anaerobic membrane bioreactor (AnMBR) for long-term co-digestion of food waste and kitchen wastewater. The OLRs were expanded from 4.5, 5.6, and 6.9 kg COD m- 3 d-1 to optimize biogas yield, nitrogen recovery, and membrane fouling at ambient temperatures of 25-32 degrees C. Results showed that specific methane production of UASB was 249 +/- 7 L CH4 kg-1 CODremoved at the OLR of 6.9 kg TCOD m- 3 d-1. Total Chemical Oxygen Demand (TCOD) loss by hydrolysis was 21.6% of the input TCOD load at the hydraulic retention time (HRT) of 2 days. However, low total volatile fatty acid concentrations were found in the AnMBR, indicating that a sufficiently high hydrolysis efficiency could be accomplished with a short HRT. Furthermore, using AnMBR structure consisting of an Upflow Anaerobic Sludge Blanket Reactor (UASB) followed by a side -stream ultrafiltration membrane alleviated cake membrane fouling. The wasted digestate from the AnMBR comprised 42-47% Total Kjeldahl Nitrogen (TKN) and 57-68% total phosphorous loading, making it suitable for use in soil amendments or fertilizers. Finally, the predominance of fine particles (D10 = 0.8 mu m) in the ultra -filtration membrane housing (UFMH) could lead to a faster increase in trans-membrane pressure during the filtration process.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 8.8
DOI: 10.1016/J.CHEMOSPHERE.2022.136537
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“On the Origin of Damped Electrochemical Oscillations at Silicon Anodes (Revisited)”. Proost J, Blaffart F, Turner S, Idrissi H, ChemPhysChem : a European journal of chemical physics and physical chemistry 15, 3116 (2014). http://doi.org/10.1002/cphc.201402207
Abstract: Electrochemical oscillations accompanying the formation of anodic silica have been shown in the past to be correlated with rather abrupt changes in the mechanical stress state of the silica film, commonly associated with some kind of fracture or porosification of the oxide. To advance the understanding on the origin of such oscillations in fluoride-free electrolytes, we have revisited a seminal experiment reported by Lehmann almost two decades ago. We thereby demonstrate that the oscillations are not stress-induced, and do not originate from a morphological transformation of the oxide in the course of anodisation. Alternatively, the mechanical features accompanying the oscillations can be explained by a partial relaxation of the field-induced electrostrictive stress. Furthermore, our observations suggest that the oscillation mechanism more likely results from a periodic depolarisation of the anodic silica.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.075
Times cited: 5
DOI: 10.1002/cphc.201402207
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“Rational design of Ag/TiO2 nanosystems by a combined RF-sputtering/sol-gel approach”. Armelao L, Barreca D, Bottaro G, Gasparotto A, Maccato C, Tondello E, Lebedev OI, Turner S, Van Tendeloo G, Štangar UL, ChemPhysChem : a European journal of chemical physics and physical chemistry 10, 3249 (2009). http://doi.org/10.1002/cphc.200900571
Abstract: The present work is devoted to the preparation of Ag/TiO2 nanosystems by an original synthetic strategy, based on the radio-frequency (RF) sputtering of silver particles on titania-based xerogels prepared by the sol-gel (SG) route. This approach takes advantage of the synergy between the microporous xerogel structure and the infiltration power characterizing RF-sputtering, whose combination enables the obtainment of a tailored dispersion of Ag-containing particles into the titania matrix. In addition, the systems chemico-physical features can be tuned further through proper ex situ thermal treatments in air at 400 and 600 °C. The synthesized composites are extensively characterized by the joint use of complementary techniques, that is, X-ray photoelectron and X-ray excited Auger electron spectroscopies (XPS, XE-AES), secondary ion mass spectrometry (SIMS), glancing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), electron diffraction (ED), high-angle annular dark field scanning TEM (HAADF-STEM), energy-filtered TEM (EF-TEM) and optical absorption spectroscopy. Finally, the photocatalytic performances of selected samples in the decomposition of the azo-dye Plasmocorinth B are preliminarily investigated. The obtained results highlight the possibility of tailoring the system characteristics over a broad range, directly influencing their eventual functional properties.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.075
Times cited: 56
DOI: 10.1002/cphc.200900571
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“The role of oxygen at the interface between titanium and carbon nanotubes”. Felten A, Suarez-Martinez I, Ke X, Van Tendeloo G, Ghijsen J, Pireaux J-J, Drube W, Bittencourt C, Ewels CP, ChemPhysChem : a European journal of chemical physics and physical chemistry 10, 1799 (2009). http://doi.org/10.1002/cphc.200900193
Abstract: We study the interface between carbon nanotubes (CNTs) and surface-deposited titanium using electron microscopy and photoemission spectroscopy, supported by density functional calculations. Charge transfer from the Ti atoms to the nanotube and carbide formation is observed at the interface which indicates strong interaction. Nevertheless, the presence of oxygen between the Ti and the CNTs significantly weakens the Ti-CNT interaction. Ti atoms at the surface will preferentially bond to oxygenated sites. Potential sources of oxygen impurities are examined, namely oxygen from any residual atmosphere and pre-existing oxygen impurities on the nanotube surface, which we enhance through oxygen plasma surface pre-treatment. Variation in literature data concerning Ohmic contacts between Ti and carbon nanotubes is explained via sample pre-treatment and differing vacuum levels, and we suggest improved treatment routes for reliable Schottky barrier-free Ti-nanotube contact formation.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.075
Times cited: 38
DOI: 10.1002/cphc.200900193
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