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General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Electrochimie, Electrochemistry, Cinétique et mécanisme des réactions, Kinetics and mechanism of reactions, Carbone, Carbon, Carbono, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur, Catalyst, Catalizador, Durabilité, Durability, Durabilidad, Dynamique, Dynamics, Dinámica, Electrocatalyse, Electrocatalysis, Electrocatálisis, Nanofil, Nanowires, Protection environnement, Environmental protection, Protección medio ambiente, Support, Soporte, Dynamic drive cycle testing, PEMFCs, PtNW/C electrocatalyst, and Stack

Carbon supported platinum nanowires (PtNW/C) synthesized by a simple and inexpensive template-free methodology has been used for the first time as a cathode catalyst in a 15 cell with an active area of 250 cm2, 1.5 kW proton exchange membrane fuel cell (PEMFC) stack. Drive cycle testing along with in-situ and ex-situ accelerated degradation testing (ADT) showed that the PtNW/C catalyst exhibited better durability than commercial Pt/C. After a 420 h dynamic drive cycle durability testing, the PEMFC stacks exhibited a performance degradation rate of 14.4% and 17.9% for PtNW/C and commercial Pt/C based cathodes, respectively. It was found that the majority of performance loss was due to degradation of the commercial Pt/C anode materials, resulting from the rapidly changing load frequencies used in the testing protocol, ultimately leading to harsh fuel/air starvation conditions and subsequent Pt nanoparticle growth and agglomeration. Notably, based on post-testing characterization, the structure, electrochemically active surface area (ECSA) and oxygen reduction activity of the PtNW/C cathode catalyst remained unchanged during the drive cycling, indicating its excellent stability under these practical conditions. Conversely, when using commercial Pt/C as a cathode catalyst, significant Pt nanoparticle growth and agglomeration were observed, resulting in the reduced PEMFC stack durability. Therefore, PtNW/C materials are presented as promising replacements to conventional Pt/C as cathode electrocatalysts for PEMFCs, and particularly demonstrate improved stability under the practical conditions encountered for automotive applications.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Photochimie, Photochemistry, Etat colloïdal et états dispersés, Colloidal state and disperse state, Matériaux poreux, Porous materials, Composé binaire, Binary compound, Compuesto binario, Composé de métal de transition, Transition element compounds, Matériau poreux, Porous material, Material poroso, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Mésoporosité, Mesoporosity, Mesoporosidad, Oxyde de titane, Titanium oxide, Titanio óxido, Photocatalyse, Photocatalysis, Fotocatálisis, Protection environnement, Environmental protection, Protección medio ambiente, Silice, Silica, Sílice, Synthèse, Synthesis, Síntesis, Photocatalyseur, Photocatalyst, SiO2, Hierarchical macro-mesoporous silica, Si-Cr-Ti, and Visible-light driven photocatalysis

Hierarchical macro-mesoporous silica materials co-incorporated with Crand Ti were directly synthesized by adopting close-packed array of polystyrene microsphere as hard template for macropore through a simple soaking-calcination way, where Si/Ti ratio was fixed at 200 and Si/Cr ratio was set between 200 and 10. Ti specie is highly dispersed in porous matrix and Cr specie mainly exists as tetra-coordinated CrO3 at higher Si/Cr ratio (Si/Cr ≥ 50), which transforms to a mixture of CrO3 and crystallized hexa-coordinated Cr2O3when Si/Cr ratio is below 50. This highly interconnected porous material co-incorporated with Cr and Ti presents highest visible-light driven photocatalytic activity at Si/Cr = 20 toward degradation of A07. Moreover, macro-mesoporous photocatalyst presents higher activity than those of macroporous and mesoporous ones at the same Si/Cr ratio. The improved visible light driven catalytic activity is mainly attributed to effective metal to metal charge transfer from Cr(VI) to Ti(IV) benefitted from the uniform dispersion of these two species in hierarchical porous silica matrix.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Acide carboxylique, Carboxylic acid, Acido carboxílico, Composé de métal de transition, Transition element compounds, Acide formique, Formic acid, Fórmico ácido, Acide lactique, Lactic acid, Láctico ácido, Acide organique, Organic acids, Acido orgánico, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Condition hydrothermale, Hydrothermal condition, Condición hidrotermal, Magnésie, Magnesia, Oxyde de cuivre, Copper oxide, Cobre óxido, Protection environnement, Environmental protection, Protección medio ambiente, Réaction catalytique, Catalytic reaction, Reacción catalítica, Sucre, Sugar, Azúcar, Synthèse, Synthesis, Síntesis, Alkaline hydrothermal synthesis, Copper oxide catalysis, and Sugars

Design of a suitable catalyst for the conversion of inedible-biomass, a renewable resource, into high-value chemicals is an immense and important area of research in an era of energy crisis. This paper demonstrates batch conversion of sugars into lactic acid (LA) and formic acid (FA) employing a supported copper catalyst. A magnesia-supported copper catalyst was synthesized by a hydrothermal methodology using CTAB as the capping agent (denoted as CuCTAB/MgO). We found that the CuCTAB/MgO not only dramatically boosted the yields of LA and FA from sugars but also decreased the energy demand of the process by decreasing the reaction temperature from 523 K to 393 K. The high yields of LA (70%) in the presence of NaOH and of FA (65%) in the presence of H2O2 were achieved from glucose at 393 K in water using a CuCTAB/MgO catalyst, which could be recycled without any significant loss of activity. The copper catalyst was also found to exhibit excellent activity for the transformation of other sugars. The catalyst was characterized using PXRD, H2-TPR, N2 adsorption-desorption, and other analytical techniques to investigate the active Cu species and propose a plausible mechanistic pathway to LA.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Photochimie, Photochemistry, Etat colloïdal et états dispersés, Colloidal state and disperse state, Etudes physiques et chimiques. Granulométrie. Phénomènes électrocinétiques, Physical and chemical studies. Granulometry. Electrokinetic phenomena, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Dégradation photochimique, Photochemical degradation, Degradación fotoquímica, Microparticule, Microparticle, Micropartícula, Microsphère, Microsphere, Microsfera, Mécanisme, Mechanism, Mecanismo, Oxyde de bismuth, Bismuth oxide, Bismuto óxido, Particule sphérique, Spherical particle, Partícula esférica, Photocatalyse, Photocatalysis, Fotocatálisis, Protection environnement, Environmental protection, Protección medio ambiente, Précurseur, Precursor, Synthèse, Synthesis, Síntesis, Photodegradation mechanism, Visible-light photocatalysis, o-Phenylphenol, p-n junction, and β-Bi2O3/Bi2O2CO3 microspheres

Novel flower-like heterostructured β-Bi2O3/Bi2O2CO3 microspheres are synthesized by calcining a Bi2O2CO3 self-sacrifice precursor for the visible-light photocatalytic degradation of o-phenylphenol (OPP. is a widely used fungicide and preservative agent). The Bi2O2CO3 microspheres are firstly prepared under hydrothermal conditions, and then converted to Bi2O3 by thermal treatment. With increasing the calcining temperature from 250 to 500 °C, an in situ stepwise decomposition reaction take place during the course of calcination, described as: Bi2O2CO3 → β-Bi2O3/Bi2O2CO3 → β-Bi2O3 → β-Bi2O3/α-Bi2O3 → α-Bi2O3. The β-Bi2O3/Bi2O2CO3 microspheres synthesized at 300 °C exhibit excellent photocatalytic activity under visible-light irradiation, which can degrade 99.8% OPP in 45 min. And the degradation rate of the heterostructured photocatalyst is approximately 2, 2.6, 6, 13, 80, and 827 times higher than that of single P-Bi2O3, mixed β-Bi2O3 and Bi2O2CO3, commercial β-Bi2O3, α-Bi2O3, N-doped TiO2, and Bi2O2CO3, respectively. The superior photoreactivity of the β-Bi2O3/Bi2O2CO3 is attributed to the enhanced charge separation and transfer due to the formation of p-n junction with large heterojunction interface, favorable band gap energy (2.27 eV), relatively high specific surface areas (12.5 m2 g-1), and flower-like hierarchical micro/nano structures. In addition, the degradation intermediates including ethyl phenethyl ether, phenyl acetaldehyde, and phenylacetic acid are identified. And the results also reveal that the photogenerated holes and •O2- radicals are primarily reactive species in the photocatalytic system, which are the key factors responsible for the nearly complete mineralization of OPP.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Ammoniac, Ammonia, Amoníaco, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur, Catalyst, Catalizador, Chabazite, Chabasita, Echange ion, Ion exchange, Cambio iónico, Etat solide, Solid state, Estado sólido, Moteur diesel, Diesel engine, Motor diesel, Oxyde d'azote, Nitrogen oxide, Nitrógeno óxido, Protection environnement, Environmental protection, Protección medio ambiente, Réaction catalytique, Catalytic reaction, Reacción catalítica, Réaction one pot, One pot reaction, Reacción one pot, Réduction chimique, Chemical reduction, Reducción química, Synthèse, Synthesis, Síntesis, Zéolite, Zeolite, Zeolita, SAPO-34, Cu/SAPO-34, Emission control, NOx, and Selective catalytic reduction

Cu/SAPO-34 catalysts are synthesized using two methods: solid-state ion exchange (SSIE) and one-pot synthesis. SSIE is conducted by calcining SAPO-34/CuO mixtures at elevated temperatures. For the one-pot synthesis method, Cu-containing chemicals (CuO and CuSO4) are added during gel preparation. A high-temperature calcination step is also needed for this latter method. Catalysts are characterized with surface area/pore volume measurements, temperature programmed reduction (TPR), electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopies, and scanning electron microscopy (SEM). Catalytic properties are examined using standard ammonia selective catalytic reduction (NH3-SCR) and ammonia oxidation reactions. For Cu/SAPO-34 samples prepared by SSIE, Cu presents both as isolated Cu2+ ions and unreacted CuO. The former are highly active and selective in NH3-SCR, while the latter catalyzes a side reaction; notably, the non-selective oxidation of NH3 above 350°C. Using the one-pot method followed by a high-temperature aging treatment, it is possible to form Cu/SAPO-34 samples with predominately isolated Cu2+ ions at low Cu loadings. However at much higher Cu loadings, isolated Cu2+ ions that bind weakly with the CHA framework and CuO clusters also form. These Cu moieties are very active in catalyzing non-selective NH3 oxidation above 350°C. At very low reaction temperature temperatures (<155°C), standard NH3-SCR over Cu/SAPO-34 catalysts appears to be kinetically limited. However at higher temperatures, multiple rate limiting factors are possible.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Photochimie, Photochemistry, Alcool, Alcohol, Composé benzénique, Benzenic compound, Compuesto bencénico, Composé de métal de transition, Transition element compounds, Autoorganisation, Self organization, Autoorganización, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Dégradation photochimique, Photochemical degradation, Degradación fotoquímica, Nanotube, Nanotubo, Oxyde de titane, Titanium oxide, Titanio óxido, Phénol, Phenol, Fenol, Phénols, Phenols, Fenoles, Protection environnement, Environmental protection, Protección medio ambiente, Synthèse, Synthesis, Síntesis, Titanate, Titanates, Titanato, Photocatalytic degradation of phenol, and Self organized TiO2 nanotube layers

This study proposes a direct synthetic route to single titanate sheets through the mild and versatile conditions of the chimie douce. The stages of the production include the complexation of the titanium alkoxide precursor by benzoic acid, the formation of titanium oxo-clusters and their controlled transformation into single sheet titanates during the hydrolysis stage. The resulted material appears to be an excellent precursor for self-organized TiO2 nanotubes formation which presents an excellent activity as photocatalyst in the photo-degradation of phenol.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Composé binaire, Binary compound, Compuesto binario, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur, Catalyst, Catalizador, Composé de lanthanide, Lanthanide compound, Lantánido compuesto, Cordiérite, Cordierite, Cordierita, Gaz synthèse, Synthesis gas, Gas síntesis, Méthane, Methane, Metano, Oxyde de cérium, Cerium oxide, Cerio óxido, Protection environnement, Environmental protection, Protección medio ambiente, Reformage vapeur, Steam reforming, Reformación vapor, CeO2, CH4 oxy-steam reforming, Ceria carrier, Cordierite monoliths, Rh Pt Ni catalysts, and Syngas production

The deposition of catalytic layers as Rh, Pt, Ni (noble metals load equal to 1.5 wt.%, Ni load equal to 7.5 wt.%) on CeO2, over cordierite monoliths (400 cpsi, diameter 1 cm, length 1.5 cm), prepared through a combination of the solution combustion synthesis followed by the Wet Impregnation technique, was investigated. The performances of the structured catalysts were evaluated towards the methane Oxy-Steam Reforming (OSR) reaction. The physicochemical properties of the catalysts at powder level were investigated by X-ray Diffraction, CO chemisorption and nitrogen adsorption (BET), whereas the characteristics of the structured catalysts in terms of thickness and coating integrity were investigated by Scanning Electron Microscopy (SEM), mechanical strength and pressure drop tests. Moreover, the morphology of catalytic layers was investigated by Transmission Electron Microscopy (TEM) on the powder obtained by mechanically scraping the monoliths internal walls. The prepared structured catalysts were tested and compared towards the CH4 OSR reaction varying the temperature (500-800°C), the weight space velocity (WSV = 33,000-400,000 Nml gcat-1 h-1), at fixed molecular oxygen-to-carbon (O/C = 0.55) and steam-to-carbon (S/C = 1.2) molar ratios. The catalytic monoliths presented a uniform thin coating with thickness between 20 and 25 μm, high mechanical strength and low pressure drop. Regarding the catalytic activity, at low WSV all of the structured catalysts showed similar performances. Instead, increasing the WSV, the catalytic monolith loaded with 1.5 wt.% Rh/CeO2 performed slightly better than the other samples, maintaining almost constant the methane conversion and the CO selectivity even at 400,000 Nml gcat-1 h-1.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Photochimie, Photochemistry, Alcool, Alcohol, Composé benzénique, Benzenic compound, Compuesto bencénico, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Chlorophénol, Chlorophenol, Clorofenol, Composé du chlore, Chlorine compounds, Cloro compuesto, Dégradation, Degradation, Degradación, Minéralisation, Mineralization, Mineralización, Nanocomposite, Nanocompuesto, Oxyde de bismuth, Bismuth oxide, Bismuto óxido, Photocatalyse, Photocatalysis, Fotocatálisis, Phénols, Phenols, Fenoles, Protection environnement, Environmental protection, Protección medio ambiente, Photocatalyseur, Photocatalyst, 2-Chlorophenol degradation, 2-Nitrophenol degradation, Bi2O3 based photocatalyst, and Sunlight photocatalysis

The photocatalytic mineralization of 2-chlorophenol (2-CP) and 2-nitrophenol (2-NP) was investigated using α-Bi2O3. The experiments were performed both in complete spectrum and in the visible region (420-800 nm) of the sunlight. The materials were fully characterized by means of UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FESEM). α-Bi2O3 showed considerably higher activity for the mineralization of 2-nitrophenol and 2-chlorophenol under natural sunlight exposure, however still appreciable activity was observed in the visible region. Formation of surface nanocomposites Bi2O4-x-Bi2O3 was observed under sunlight irradiation due to the presence of UV light. The sunlight exposed Bi2O3, i.e. Bi2O4-xBi2O3 composite, showed excellent activity for the degradation and mineralization of 2-CP and 2-NP in the visible region of sunlight. A key role of both hydroxyl and superoxide anion radicals was evidenced in the degradation and mineralization processes under sunlight while only hydroxyl radicals were identified as major facilitators under visible light irradiation.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Sciences appliquees, Applied sciences, Energie, Energy, Combustibles, Fuels, Combustibles de remplacement. Production et utilisation, Alternative fuels. Production and utilization, Hydrogène, Hydrogen, Métal transition, Transition metal, Metal transición, Platinoïde, Platinoid, Platinoide, Carbone, Carbon, Carbono, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur, Catalyst, Catalizador, Hydrogénation, Hydrogenation, Hidrogenación, Hydrure, Hydrides, Hidruro, Hétérocycle, Heterocyclic compound, Heterociclo, Liquide, Liquid, Líquido, Protection environnement, Environmental protection, Protección medio ambiente, Ruthénium, Ruthenium, Rutenio, Réaction catalytique, Catalytic reaction, Reacción catalítica, Réactivité chimique, Chemical reactivity, Reactividad química, Stockage hydrogène, Hydrogen storage, Structure, Estructura, Substitution, Substitución, Heterocyclic compounds, Liquid organic hydride, and Ruthenium catalysts

The effect of the type of heteroatom in the structure on the recyclability of possible candidate compounds for application as LOC (liquid organic carriers) was studied by comparing the rate and selectivity obtained in hydrogenation of carbazole, dibenzothiophene, dibenzofuran and fluorene. The effect of a partial saturation of the compound on its hydrogenation yield and reaction pathway was also considered by studying hydrogenation of 1,2,3,4-tetrahydrocarbazole. Using Ru black catalyst, the rate of hydrogenation was found to decrease in order; dibenzofuran > 1,2,3,4-tetrahydrocarbazole > carbazole » fluorene. No reaction was observed in the hydrogenation of dibenzothiophene under the conditions studied which was attributed to the immediate poisoning of ruthenium metal by sulphur compounds. The rate of hydrogenation of fluorene was around 3 times lower as compared to carbazole and over 8 times lower as compared to that of dibenzofuran under the same reaction conditions. With the exeption of S containing dibenzothiophene, the presence of the heteroatom in the structure was found to be beneficial in terms of increasing the rate of hydrogen loading step. Additionally, a higher reaction rate was obtained in the hydrogenation of the partially saturated 1,2,3,4-tetrahydrocarbazole as compared to the substrate carbazole. The structure and stability of intermediates was found to be significantly influenced by the type and presence of a heteroatom in the structure. A stable octahydro-intermediate was observed only with N-heterocycles, whereas a stable hexahydro-intermediate was produced in the polyaromatic hydrocarbon-fluorene. Additionally, the theoretically obtained lowest total enthalpies using DFT calculations agreed well with the stable intermediates observed experimentally in the hydrogenation of fluorene. Theoretical DFT differences in enthalpies also indicated the products of hydrogenolysis of perhydro-dibenzofuran to be the most favourable products of its hydrogenation, which agreed well with the experimental observations. Overall, taking into account the recyclability of LOC, substitution of carbon with a N heteroatom was demonstrated to be one of the promising approaches to improve the kinetics of the hydrogen loading step.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Acide carboxylique, Carboxylic acid, Acido carboxílico, Composé binaire, Binary compound, Compuesto binario, Composé de lanthanide, Lanthanide compound, Lantánido compuesto, Métal transition, Transition metal, Metal transición, Acide acétique, Acetic acid, Acético ácido, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Composé de métal de transition, Transition element compounds, Gazéification, Gasification, Gasificación, Matière volatile, Volatiles, Materia volátil, Nickel, Niquel, Oxyde de cérium, Cerium oxide, Cerio óxido, Protection environnement, Environmental protection, Protección medio ambiente, Reformage vapeur, Steam reforming, Reformación vapor, Zircone, Zirconia, Zircona, CeO2, ZrO2, Ceria-zirconia, and Humin

Acetic acid and phenols are the major components of the condensable by-products in the low temperature de-volatilisation stage of humin during gasification. Catalytic steam reforming of acetic acid using supported Ni on ceria-zirconia mixed oxide prepared via the hydrothermal route is discussed. The influence of steam reforming temperatures, steam/carbon ratios were studied. The catalyst showed high activity and good stability. Furthermore, activity improvement was achieved with multiple redox cycles as relevant to recycling the catalysts. Characterisation of the fresh and used catalyst by various techniques (e.g., LEIS, Raman spectroscopy, TPO/TPR) revealed the modification of metal-oxygen bond on the support under the steam reforming conditions. It in turn improved the oxygen mobility of the catalyst.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie de surface, Surface physical chemistry, Métal transition, Transition metal, Metal transición, Adsorption, Adsorción, Carbone, Carbon, Carbono, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur mixte, Mixed catalyst, Catalizador mixto, Gaz à l'eau, Water gas, Gas con agua, Glycérol, Glycerol, Glicerol, Hydrogène, Hydrogen, Hidrógeno, Nanotube multifeuillet, Multiwalled nanotube, Nanotubo pared múltiple, Nickel, Niquel, Palladium, Paladio, Platine, Platinum, Platino, Platinoïde, Platinoid, Platinoide, Protection environnement, Environmental protection, Protección medio ambiente, Reformage, Reforming, Reformación, Sorption, Sorción, Support, Soporte, Bimetallic catalyst, CO2 removal, Platinum-nickel, Platinum-palladium, and Water-gas shift

In this study, multi-walled carbon nanotubes supported Pt and Pt-based bimetallic catalysts were prepared and their catalytic activities were investigated to screen effective and economical catalyst for H2 production in catalytic aqueous phase reforming (CAPR) of glycerol. Nickel promoted Pt catalyst with optimized Ni:Pt molar ratio afforded highest glycerol conversion rate (81.21%) and carbon conversion to gas (15.3%) although hydrogen gasification ratio (7.2%) was poorer than that of noble metals promoted Pt-based bimetallic catalysts. Adding CaO significantly enhanced the fraction and selectivity of H2 over Pt-Ni catalyst and those of CH4 were reduced to a negligible level, which was possibly attributed to the facilitated water-gas shift reaction and inhibited methanation through in-situ CO2 sorption via carbonation. Results suggested that Pt-Ni bimetallic catalysts improved dehydrogenation-decarboxylation and dehydration-hydrogenation reactions, leading to high glycerol conversions. Introducing CaO further favored C-C bond cleavage towards high H2 yield. The catalytic performance can be completely recovered after regenerating the catalyst and adding sacrificial CaO. In terms of reduced consumption of precious metal catalyst, excellent catalyst performance and hydrothermal stability, combination of Pt-Ni bimetallic catalyst and CaO additive was identified as an effective catalytic system for H2 production in CAPR of glycerol.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Photochimie, Photochemistry, Aldéhyde, Aldehyde, Aldehído, Composé de métal de transition, Transition element compounds, Acétaldéhyde, Acetaldehyde, Acetaldehído, Anatase, Anatasa, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Décomposition, Decomposition, Descomposición, Nanoplaque, Nanoplate, Nanoplaca, Oxydation, Oxidation, Oxidación, Oxyde de titane, Titanium oxide, Titanio óxido, Photocatalyse, Photocatalysis, Fotocatálisis, Protection environnement, Environmental protection, Protección medio ambiente, Synthèse solvothermale, Solvothermal synthesis, Síntesis solvotermal, Acetaldehyde decomposition, Anatase nanoplates, Mn4+/TiO2, NO oxidation, and {0 0 1} facets

The photocatalytic activity of TiO2 and manganese doped TiO2 nanoplates with various manganese atomic percentages, in the range of 2-7%, was studied. The undoped and doped nanoplates with exposed {0 0 1} facets were produced by a solvothermal method. The crystal structure as well as the shape of the TiO2 and Mn4+/TiO2 anatase nanoparticles was determined with X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). Both techniques revealed that the nanocrystals are in the form of plates. Moreover, the anisotropic peak broadening of the X-ray diffraction patterns was studied using the Rietveld refining method. Chemical analysis of the photocatalyst that was carried out with X-ray photoelectron spectroscopy (XPS) showed the presence of manganese ions in the TiO2 anatase matrix. The Density Functional Theory (DFT) calculations exhibited a decrease in the energy gap and an increase in the density of the electronic stated inside the gap for the doped TiO2. These observations were in agreement with the results of the UV-visible diffuse reflectance spectroscopy (DRS) that demonstrated an adsorption shift towards the visible region for the same samples. The photocatalytic activity of the synthesized catalysts was investigated by the photocatalytic oxidation of the gaseous nitric oxide (NO) and decomposition of the gaseous acetaldehyde (CH3CHO) under visible light irradiation. The optimal concentration of dopant that improves the photocatalytic activity of the nanoplates was determined.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Photochimie, Photochemistry, Composé de métal de transition, Transition element compounds, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Conversion, Conversión, Déchet, Wastes, Desperdicio, Eau mer, Seawater, Agua mar, Electrode, Electrodes, Electrodo, Energie solaire, Solar energy, Energía solar, Oxyde de titane, Titanium oxide, Titanio óxido, Photocatalyse, Photocatalysis, Fotocatálisis, Protection environnement, Environmental protection, Protección medio ambiente, Rayonnement solaire, Solar radiation, Radiación solar, Réduction chimique, Chemical reduction, Reducción química, Uranium, Uranio, Metal reduction, Nuclear wastes, Photocatalytic, and Superoxide

Uranium(VI) spiked in natural seawater was photoelectrochemically reduced using porous TiO2 film electrodes at varying potential biases (EbiasS) and pH values. Linear sweep voltammograms of TiO2 electrodes in seawater with U(VI) at pH 8.2 exhibited the characteristic reduction peaks at -0.95 VSCE and anodic peaks at -0.75 VSCE. These peaks shifted anodically and became less pronounced with decreasing pH values from 8.2 to 3. At the natural seawater pH of 8.2, photoelectrochemical (PEC) treatment (Ebias = -1.0VSCE; AM 1.5 G) was found to be considerably more effective in reducing U(VI) than photocatalytic (PC) treatment (without Ebias) and electrochemical (EC) treatment (without irradiation), and even the combination of the two treatment processes. The synergistic effect of the PEC U(VI) reduction varied depending on the EbiasS and pH values, and was further confirmed by the Faradaic efficiency (e), which was close to 100%. Inductively coupled plasma spectroscopy (ICP) and detailed surface analyses of the TiO2 using various techniques (TEM/EDX, SEM/EDX, and XPS) indicated that ∼95% of uranium in the PEC-treated experiment was adsorbed on TiO2 with 57% as U4.6+ and 14% as U4+, whereas ∼98% of uranium in the EC-treated experiment remained in solution, containing 62% as U4.6+ and 12% as U4+. Under certain conditions (e.g., at a pH of 3.0 and/or with N2-purging), no reduction of U(VI) was observed irrespective of the Ebias and irradiation. To further investigate the observed lack of U(VI) reduction, surface chemistry and energetics between TiO2 and U(VI) were studied as a function of pH. Finally, a role of superoxide radicals as an electron shuttle between TiO2 and U(VI) was established as a primary U(VI) reduction mechanism.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Etat colloïdal et états dispersés, Colloidal state and disperse state, Etudes physiques et chimiques. Granulométrie. Phénomènes électrocinétiques, Physical and chemical studies. Granulometry. Electrokinetic phenomena, Composé binaire, Binary compound, Compuesto binario, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur, Catalyst, Catalizador, Composé de lanthanide, Lanthanide compound, Lantánido compuesto, Composé de métal de transition, Transition element compounds, Décomposition, Decomposition, Descomposición, Nanoparticule, Nanoparticle, Nanopartícula, Nanosphère, Nanosphere, Nanosfera, Oxyde d'azote, Nitrogen oxide, Nitrógeno óxido, Oxyde de cérium, Cerium oxide, Cerio óxido, Particule sphérique, Spherical particle, Partícula esférica, Protection environnement, Environmental protection, Protección medio ambiente, Protoxyde d'azote, Nitrogen protoxide, Nitrógeno protóxido, Réaction catalytique, Catalytic reaction, Reacción catalítica, CeO2, CuO, CeO2 nanospheres, CuO-CeO2 catalysts, N2O decomposition, Small CuO clusters, and Synergetic effect

High surface area CeO2 nanospheres as an active catalyst support were synthesized using glycothermal approach. Different loadings of copper (4, 6, 10 and 15 wt.%) were supported by wet impregnation method. Prepared materials were characterized by means of TEM, SEM-EDX, XRD, UV-Vis diffuse reflectance, N2 adsorption/desorption, DRIFT and H2-TPR techniques, and tested for the catalytic reaction of nitrous oxide decomposition. The best activity in the N2O degradation was found for the sample containing 10 wt.% of Cu that can be attributed to the highest number of small CuO clusters on the catalyst surface. Further increase of copper content strongly affects the dispersion and leads to the formation of less active segregated CuO phase, which was confirmed by XRD, UV-Vis and H2-TPR results. Accordingly to UV-Vis examination and DRIFT analysis using CO as a probe molecule, all solids contain Cu+1 ions which play a crucial role in the N2O decomposition mechanism. The synthesized catalysts were also tested in wet or NO containing atmospheres, where an inhibiting effect takes place and leads to shifting of conversion profiles to higher temperature by 65 and 10 °C, correspondingly. It was found out that the formation of a new, crystalline CuO·3H2O phase occurs in water vapour containing atmosphere, which can result in catalyst deactivation. However, this effect is fully reversible and the catalyst is able to replenish initial activity in dry atmosphere. Potentiality of CuO/CeO2 materials in catalytic N2O decomposition in industrial processes was confirmed by long-term stability tests performed in the period of 50 h in the presence of inhibiting gas components.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Composé binaire, Binary compound, Compuesto binario, Composé de métal de transition, Transition element compounds, Acide, Acids, Acido, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur sur support, Supported catalyst, Catalizador sobre soporte, Composé de lanthanide, Lanthanide compound, Lantánido compuesto, Hydrogénation, Hydrogenation, Hidrogenación, Oxyde de cérium, Cerium oxide, Cerio óxido, Oxyde de zirconium, Zirconium oxide, Zirconio óxido, Phase liquide, Liquid phase, Fase líquida, Protection environnement, Environmental protection, Protección medio ambiente, Réaction catalytique, Catalytic reaction, Reacción catalítica, Réduction chimique, Chemical reduction, Reducción química, Solution solide, Solid solution, Solución sólida, CeO2, ZrO2, CeO2-ZrO2 solid solutions, Liquid-phase catalytic hydrogenation, Simultaneous reduction of monochloroacetic acid and bromate, and Supported Pd catalysts

Palladium catalysts supported on ZrO2, CeO2 and CeO2-ZrO2 solid solutions were prepared using the deposition-precipitation method, and individual and simultaneous reduction of monochloroacetic acid (MCAA) and bromate by liquid-phase catalytic hydrogenation on these catalysts was investigated. The catalysts were characterized by N2 adsorption-desorption, X-ray diffraction, measurement of point of zero charge, X-ray photoelectron spectroscopy and CO chemisorption. Characterization results showed that CeO2-ZrO2 solid solutions with varied Ce/Zr ratios had nearly identical points of zero charge to those of ZrO2 and CeO2. For supported Pd catalysts, the binding energy of Pd 3d5/2 of Pd/CeO2 was found to be higher than that of Pd/ZrO2, indicative of a stronger metal-support interaction in the former. Given a similar Pd loading, Pd dispersion of Pd/Ce1-xZrxO2 first increased and then decreased with CeO2 content, and the highest Pd dispersion was observed on Pd(0.86)/Ce0.8Zr0.2O2. Accordingly, Pd/Ce1-xZrxO2 exhibited much higher catalytic activities than Pd/ZrO2 at a Pd loading amount of around 0.85 wt.%, and the highest activity was identified on Pd(0.86)/Ce0.8Zr0.2O2 for individual reduction of bromate and MCAA. The turnover frequencies of Pd(0.86)/Ce0.8Zr0.2O2 for the reduction of bromate and MCAA were 0.69 and 0.23 s-1, respectively, which were one order of magnitude higher than the supported Pd catalysts previously reported. For the simultaneous reduction of MCAA and bromate, the presence of bromate completely suppressed MCAA reduction on Pd(0.85)/ZrO2, while both MCAA and bromate could be effectively reduced on Pd(0.86)/Ce0.8Zr0.2O2. Additionally, the simultaneous reduction of bromate and MCAA proceeded via a competitive reaction mechanism, and the reduction rate of bromate or MCAA was negatively correlated to the competitor concentration.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Photochimie, Photochemistry, Electrochimie, Electrochemistry, Photoélectrochimie. Electrochimiluminescence, Photoelectrochemistry. Electrochemiluminescence, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Dopage, Doping, Graphite, Grafito, In situ, Nanostructure, Nanoestructura, Nitrure de carbone, Carbon nitrides, Photocatalyse, Photocatalysis, Fotocatálisis, Photoélectrochimie, Photoelectrochemistry, Fotoelectroquímica, Protection environnement, Environmental protection, Protección medio ambiente, Nanofeuillet, Nanosheet, Graphite-like carbon nitride, Heterojunction, Mott-Schottky effect, and Nanosheets

A novel mesoporous ternary photocatalyst consisting of g-C3N4 nanosheets, metallic silver and MoS2 nanosheets is prepared using AgNO3 as a multifunctional modifier during thermal polymerization of melamine and few-layer MoS2 in a simple one-pot process. The gas bubbles from AgNO3 form an extra soft templates to in situ alter the polymerization behavior of melamine, creating thin g-C3N4 nanosheets and large porous structure that exhibit enhanced light absorption. The solution-based, soft-chemical synthesis enables homogeneous inclusion of metallic silver in the g-C3N4 nanosheets and high dispersibility of ultrathin MoS2 nanosheets in the obtained nanocomposite. In situ coupling between metallic silver and g-C3N4 nanosheets produces nanoscale Mott-Schottky effect, provides an effective channel for charge separation and transfer, and tunes energy band of the latter. More importantly, modulated energy band of g-C3N4 nanosheets synergistically expedites the separation and transfer of photogenerated electron-hole pairs at the interface of two-dimensional g-C3N4/MoS2 heterojunction. As a result, the ternary nanocomposite exhibits improved photoelectrochemical performance and photocatalytic activity under simulated sunlight irradiation compared with other reference materials. Our results provide new insights into the design and large-scale production of semiconductor photocatalyst.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Composé binaire, Binary compound, Compuesto binario, Composé de lanthanide, Lanthanide compound, Lantánido compuesto, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur, Catalyst, Catalizador, Composé de métal de transition, Transition element compounds, Hydrocarbure, Hydrocarbon, Hidrocarburo, Monoxyde de carbone, Carbon monoxide, Carbono monóxido, Néodyme, Neodymium, Neodimio, Oxydation, Oxidation, Oxidación, Oxyde de cérium, Cerium oxide, Cerio óxido, Protection environnement, Environmental protection, Protección medio ambiente, Réaction catalytique, Catalytic reaction, Reacción catalítica, Suie, Soot, Hollín, Zircone, Zirconia, Zircona, CeO2, ZrO2, Ceria-zirconia catalyst, Diesel soot, Hydrocarbons, and Neodymium-ceria catalyst

Ce0.73-xZr0.27NdxO2 mixed oxides (x ≤ 0.3) were prepared, characterized by XRD, Raman spectroscopy, N2 adsorption isotherms and H2-TPR, and tested for simultaneous CO, propylene, benzene and soot oxidation in a gas mixture containing O2, NOx, H2O, CO2, CO, propylene (model aliphatic hydrocarbon) and benzene (model aromatic hydrocarbon) that simulates a diesel exhaust. Ce-Zr mixed oxide doping with a low atomic fraction of neodymium (0.01 ≤ x ≤ 0.09) promotes the creation of oxygen vacancies, has a minor effect in the BET specific surface areas of the oxides, increases the surface ceria reducibility and has a positive effect in the catalytic activity. On the contrary, higher neodymium atomic fractions (x = 0.2 and 0.3) promote sintering, with a drastic decrease of the BET specific surface area, surface reducibility and catalytic activity. The Ce0.73-xZr0.27NdxO2 catalysts with x ≤ 0.09 are able to accelerate simultaneously soot, propylene and benzene combustion, and as a general trend, the catalytic behavior of Ce0.73Zr0.27O2 is improved by low atomic fraction neodymium doping (0.01 ≤ x ≤ 0.09). These Ce0.73-xZr0.27NdxO2 mixed oxides with 0.01 ≤ x ≤ 0.09 are also able to accelerate CO oxidation in a certain extent, but there is a net production of CO during soot combustion because the oxidation capacity of these oxides is not high enough to oxidize all CO released as soot combustion product.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie de surface, Surface physical chemistry, Echange d'ions, Ion-exchange, Zéolites: préparations et propriétés, Zeolites: preparations and properties, Atmosphère, Atmosphere, Atmósfera, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur, Catalyst, Catalizador, Combustion, Combustión, Monoxyde de carbone, Carbon monoxide, Carbono monóxido, Protection environnement, Environmental protection, Protección medio ambiente, Réaction catalytique, Catalytic reaction, Reacción catalítica, Zéolite ZSM5, Catalytic activity, Cu-Ce/ZSM-5, and Self-sustained combustion

The Cu/ZSM-5, Ce/ZSM-5 and Cu-Ce/ZSM-5 catalysts were prepared and characterized in this investigation and the catalytic activity of carbon monoxide (CO) combustion under these catalysts was determined by temperature-programmed oxidation. The activity for the CO combustion follows the decreasing order: Cu-Ce/ZSM-5 > Cu/ZSM-5 > Ce/ZSM-5, indicated by lower ignition, light-off, extinction temperature and broader hysteresis determined via both heating and cooling feeding process. The CO adsorbed on the copper sites to form Cu+-CO complexes, monodentate and bidentate carbonates was considered to be the crucial step for CO catalytic combustion. At the CO concentration ≥5 vol.%, the CO self-sustained combustion was achieved over the Cu-Ce/ZSM-5 catalyst. One reason is due to formation of Cu2+ ions incorporated into cerium oxides, which are more reducible than the copper clusters, minicrystals and bulk CuO particles. Another reason is attributable to the formation of Ce4+/Ce3+ redox couple, which facilitates oxygen transport on the catalyst surface.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Photochimie, Photochemistry, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Dépôt, Deposition, Depósito, Photocatalyse, Photocatalysis, Fotocatálisis, Protection environnement, Environmental protection, Protección medio ambiente, Dissociation de l'eau, Water splitting, BiOCl, Photo-deposition, Photocatalytic, and Selective transport

The efficient spatial transport of photo-generated electrons and holes to different facets is critical to construct an efficient solar energy conversion system. BiOCl@Au/MnOx hierarchical structure was fabricated by depositing the Au and MnOx on the {0 0 1} and {1 1 0} crystal facets of BiOCl, respectively. The internal electric field (EIEF) along the 〈0 0 1〉 direct, and strong local electric field (ELEF) induced by the fast formed Au nanoparticles have been proposed as the intrinsic driving force for the spatial separation and transport of charge carriers in the BiOCl semiconductor, which resulted in significant enhancement of solar-driven photocatalytic activity for the pure water splitting without any sacrificial agent. The special structure of selective deposition of redox cocatalysts on the different facets of a single crystal should be promising and intriguing for designing highly efficient solar energy conversion photocatalyst.

General chemistry, physical chemistry, Chimie générale, chimie physique, Environment, Environnement, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Photochimie, Photochemistry, Etat colloïdal et états dispersés, Colloidal state and disperse state, Etudes physiques et chimiques. Granulométrie. Phénomènes électrocinétiques, Physical and chemical studies. Granulometry. Electrokinetic phenomena, Acide carboxylique, Carboxylic acid, Acido carboxílico, Composé de métal de transition, Transition element compounds, Acide formique, Formic acid, Fórmico ácido, Alliage, Alloys, Aleación, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Décomposition, Decomposition, Descomposición, Electrofilage, Electrospinning, Electrohilado, Hydrogène, Hydrogen, Hidrógeno, Nanofibre, Nanofiber, Nanofibra, Nanoparticule, Nanoparticle, Nanopartícula, Oxyde de titane, Titanium oxide, Titanio óxido, Photocatalyse, Photocatalysis, Fotocatálisis, Protection environnement, Environmental protection, Protección medio ambiente, Résonance plasmon surface, Surface plasmon resonance, AuPd alloy, and Formic acid decomposition

We present high-yield hydrogen production through selective photocatalytic decomposition of formic acid by using electrospun TiO2 nanofibers decorated with AuPd bimetallic alloy nanoparticles under simulated sunlight irradiation. By using only 5 mg of the AuPd/TiO2 nanofibers containing the 0.75% Au and 0.25% Pd, we could achieve an optimal H2 generation rate of 88.5 μmol h-1 with an apparent quantum yield at 365 nm as 15.6%. which is higher than that of the Pd/TiO2 and Au/TiO2 nanofibers by a factor of 1.6 and 4.5, respectively. The enhanced photocatalytic decomposition of formic acid for H2 generation could be attributed to the stronger electron-sink effect of AuPd alloy nanoparticles, the high selectivity of Pd for the dehydrogenation of formic acid, and the surface plasmon resonance effect of Au. More importantly, we demonstrate that the photocatalytic processes enable re-activation of the AuPd nanoparticles that were poisoned by CO during thermal decomposition of formic acid. As such, the presented AuPd/TiO2 nanofibers are promising materials for re-generation of H2 under mild conditions from liquid storage carrier of hydrogen. .