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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, 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, Electrochimie, Electrochemistry, Cinétique et mécanisme des réactions, Kinetics and mechanism of reactions, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Eau, Water, Agua, Electrocatalyse, Electrocatalysis, Electrocatálisis, Electrolyse, Electrolysis, Electrólisis, Nanotube carbone, Carbon nanotubes, Oxygène, Oxygen, Oxígeno, Protection environnement, Environmental protection, Protección medio ambiente, Dissociation de l'eau, Water splitting, Electron tunneling effect, Oxygen evolution reaction, Volcano curve, and Water electrolysis

Oxygen evolution reaction (OER) is one of the most important reactions in electrochemical energy storage and conversion systems. Thus, the development of efficient electrocatalysts with high activity and durability is of great technological and scientific significance. We demonstrate here for the first time that pristine carbon nanotubes (CNTs) composed of between 2 and 7 concentric tubes and an outer diameter of 2-5 nm have an outstanding activity for the OER in alkaline solution as compared with single-walled and multi-walled CNTs (SWNTs & MWNTs). For example, current density measured at 1.8 V (vs RHE) for the OER on triple-walled CNTs is 56 mA cm-2, ∼10 times higher than 5.9 mA cm-2 measured on SWNTs and 35 times higher than 1.6 mA cm-2 measured on MWNTs. The activity of such CNTs is significantly higher than that of conventional 20% Ru/C and 50% Pt/C electrocatalysts at high polarization potentials. Such CNTs also show an excellent stability toward OER. One hypothesis is that for the OER on CNTs with specific number of walls, efficient electron transfer occurs on the inner tubes of the CNTs most likely through electron tunneling between outer wall and inner tubes, significantly promoting the charge transfer reaction of OER at the surface of outer wall of the CNTs. For SWNTs, such separation of functionality for OER is not possible, while effective electron tunneling between outer wall and inner tubes of the CNTs diminishes as the number of walls increases due to the reduced dc bias (i.e., the driving force) across the walls or layers of MWNTs. This hypothesis is strongly supported by the observed distinctive volcano-type dependence of the electrocatalytic activity and turnover frequencies (TOF) of CNTs as a function of number of walls.

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, Etat colloïdal et états dispersés, Colloidal state and disperse state, Matériaux poreux, Porous materials, Matériau poreux, Porous material, Material poroso, Métal transition, Transition metal, Metal transición, Carbone, Carbon, Carbono, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Electrochimie, Electrochemistry, Electroquímica, Fibre carbone, Carbon fiber, Fibra carbón, Mésoporosité, Mesoporosity, Mesoporosidad, Nanomatériau, Nanostructured materials, Palladium, Paladio, Platinoïde, Platinoid, Platinoide, Protection environnement, Environmental protection, Protección medio ambiente, Réduction chimique, Chemical reduction, Reducción química, Support catalyseur, Catalyst support, Soporte catalizador, Nanobobine, Nanocoil, CO2 electroreduction, Carbon nanocoils, Carbon nanofibers, and Ordered mesoporous carbon materials

Pd nanoparticles have been supported onto different novel carbon materials to be used in the electroreduction of CO2 to high-added value products. Carbon nanocoils (CNCs), carbon nanofibers (CNFs) and ordered mesoporous carbon materials (OMCs) have been studied as support of the catalysts. In addition, Pd catalyst supported onto Vulcan XC-72R has been synthesized in order to establish a comparison with the commercial support. In this way, the influence of the carbon material on the physicochemical and electrochemical properties of the catalysts for the CO2 eiectroreduction process can be analyzed. Supports presented different morphologies and structures. CNFs and CNCs exhibited a crystalline structure with well-aligned graphitic layers and OMCs a hexagonal ordered structure composed of not crystalline carbon. Finally, Vulcan presented an intermediate structure between amorphous and graphitic. These differences do not affect significantly the average Pd crystallite size, although a different metal dispersion was found depending on the carbon material. On the other hand, cyclic voltammetry studies showed that CO2 was effectively reduced to other species at the surface of Pd/C catalysts. Additionally, it was proved that these species were adsorbed onto Pd at -1.0V vs Ag/AgCl. Finally, a different catalytic activity towards the CO2 reduction reaction was observed for the different electrocatalysts, indicating an influence of the carbon support.

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, Métal transition, Transition metal, Metal transición, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur, Catalyst, Catalizador, Chimie, Chemistry, Química, Cuivre, Copper, Cobre, Electrocatalyse, Electrocatalysis, Electrocatálisis, Graphène, Graphene, Matériau composite, Composite material, Material compuesto, Oxygène, Oxygen, Oxígeno, Protection environnement, Environmental protection, Protección medio ambiente, Réduction chimique, Chemical reduction, Reducción química, Oxyde de graphite, Graphite oxide, Composites, Copper/graphene, Oxygen reduction reaction, and Surface chemistry

A new hybrid Cu/rGO catalyst obtained by a thermal treatment of the composite of a copper-based MOF with graphite oxide exhibited a marked catalytic activity for oxygen reduction reaction (ORR) in an alkaline medium, high tolerance to methanol oxidation and superior long-term stability over 20 h. The unique architecture of the copper atoms in the 3D framework of the pristine MOF coupled with the excellent electron transfer properties of rGO lead to materials with a homogenous distribution of copper nanoparticles of specific chemistry assembled within the graphene sheets. Fast O2 adsorption and charge transfer owing to the strong interactions between copper atoms and graphite oxide resulted in highly stable and active Cu/rGO electrodes, compared to the carbonized MOF. The synergistic effect of copper and rGO in the composite leads to a superior ORR activity in terms of long-term stability and high current densities, close to the best performance reported for Pt and other metal-free electrocatalysts.

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, Etat colloïdal et états dispersés, Colloidal state and disperse state, Etudes physiques et chimiques. Granulométrie. Phénomènes électrocinétiques, Physical and chemical studies. Granulometry. Electrokinetic phenomena, Sciences appliquees, Applied sciences, Energie, Energy, Energie. Utilisation thermique des combustibles, Energy. Thermal use of fuels, Appareils de production et de conversion d'énergie: énergie thermique, énergie électrique, énergie mécanique, etc, Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc, Piles à combustible, Fuel cells, Alcanol, Alkanol, Alcool, Alcohol, Métal transition, Transition metal, Metal transición, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Electrocatalyse, Electrocatalysis, Electrocatálisis, Hydroxyde de potassium, Potassium hydroxide, Potasio hidróxido, Hyperfréquence, Microwave, Hiperfrecuencia, Irradiation hyperfréquence, Microwave irradiation, Irradiación hiperfrecuencia, Méthanol, Methanol, Metanol, Nanoparticule, Nanoparticle, Nanopartícula, Nickel, Niquel, Noir carbone, Carbon black, Carbón negro, Oxydation, Oxidation, Oxidación, Pile combustible, Fuel cell, Pila combustión, Protection environnement, Environmental protection, Protección medio ambiente, Fuel cells, KOH, and Nickel-based electrocatalyst

Ni/C electrocatalysts were prepared by chemical deposition of nickel nanoparticles on Vulcan XC-72R carbon black using microwave irradiation technique. The time of microwave irradiation during the reduction step and nickel weight percentage were varied. This was found to affect the morphology of formed Ni/C powder as shown by TEM analysis. Increasing nickel weight percentage results in the formation of more aggregated deposits. The electrocatalytic activity of different Ni/C samples towards methanol oxidation reaction in KOH solution was studied by applying cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopic techniques. Ni/C electrocatalyst containing 30wt.% Ni [Ni/C-30] shows 5.2 times higher electrocatalytic activity than that with 10 wt.% Ni [Ni/C-10]. Heating Ni/C powder into microwave oven using the pulse mode of 30s on/10s off forms the most stable electrocatalyst for prolonged oxidation reaction. Electrochemical impedance measurements show that Ni/C-30 electrocatalyst has the lowest impedance value of 0.022 kΩ cm2, while the highest one is for Ni/C-10 [0.331 kΩ cm2] in (0.4 M methanol + 0.5 M KOH) solution at 500 mV. It confirms that Ni/C-30 has the highest electrocatalytic activity towards methanol oxidation reaction.

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, Photoélectrochimie. Electrochimiluminescence, Photoelectrochemistry. Electrochemiluminescence, Composé binaire, Binary compound, Compuesto binario, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Efficacité, Efficiency, Eficacia, Electrode, Electrodes, Electrodo, Nanotube, Nanotubo, Photoélectrochimie, Photoelectrochemistry, Fotoelectroquímica, Protection environnement, Environmental protection, Protección medio ambiente, Dissociation de l'eau, Water splitting, O Zn, ZnO, Nanotubes, Photoelectrochemical, and Znln2S4

Well aligned ZnO nanorods (NRs) and nanotubes (NTs) based core/shell nanoarrays were fabricated by hydrothermal chemical conversion and directional chemical etching method and used as photoelectrochemical (PEC) electrodes. The experimental results reveal that the optimum structure is the ZnO/ZnS/ZnIn2S4 NT arrays, such a novel PEC electrode has attained a hydrogen generation efficiency of 8.86%. This better result is attributed to the enhanced absorption efficiency, appropriate gradient energy gap structure and fast electron transfer rate of one-dimensional (1D) NT, which implies a promising application in PEC water splitting. In this paper, we also focus our study on the correlation between the properties of PEC electrode and the nanoarrays structure (including nanorods and nanotubes, binary and ternary sensitizer, buffer layer), and the formation mechanism of NT based on chemical etching process. By adjusting the amount of reactants and reaction time, the core/shell nanostructure can be tuned from NR to NT and formed buffer layer.

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, Composé de métal de transition, Transition element compounds, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Monocristal, Single crystal, Nanofil, Nanowires, Oxyde de titane, Titanium oxide, Titanio óxido, Photocatalyse, Photocatalysis, Fotocatálisis, Photoélectrochimie, Photoelectrochemistry, Fotoelectroquímica, Protection environnement, Environmental protection, Protección medio ambiente, Réaction one pot, One pot reaction, Reacción one pot, Dissociation de l'eau, Water splitting, Codoping, PEC, and TiO2

Here we report a (Sn, C) cation-anion codoped single crystal TiO2 nanowire (NW) arrays as a highly efficient solar water splitting photoelectrode, able to be fabricated using a facile one pot hydrothermal synthesis method. The synergetic effects of codoping on the photoelectrochemical activity of the photoanode were investigated and compared to undoped and monodoped photoelectrodes. The (Sn, C) codoped TiO2 NW photoanode generated the highest saturated photocurrent density i.e. 2.8 mA/cm2 at 1.23 V vs RHE while yielding a maximum solar energy conversion efficiency of 1.32% at a potential of 0.55 V vs RHE - representing 60%, 94%, and 100% efficiency improvements compared to undoped, Sn doped, and C doped TiO2 NW respectively at same potential. This improvement is attributed to the synergetic effects of Sn and C codopants to lower recombination and enhance life time of photogenerated charge-separated carriers on the surface states that lead to efficient hole transfer at the photoelectrode/electrolyte interface. In addition, an increased charge carrier density and conductivity (as evidenced from electrochemical impedance spectroscopy) and the enhanced incorporation of dopants in the codoped system, compared to monodoped system as quantified by XPS, highlights the importance of codoping. The nanomaterial was characterized by XRD, TEM, SEM and Raman UV-vis measurements. This study will guide improvements in the efficiency of TiO2 for PEC water splitting using optimized codopant pairs.

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, Anode, Anodo, Carbone, Carbon, Carbono, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Eau usée, Waste water, Agua residual, Electrochimie, Electrochemistry, Electroquímica, Oxydation, Oxidation, Oxidación, Protection environnement, Environmental protection, Protección medio ambiente, Anode materials, Carbon felt, Electro-Fenton, Electrochemical oxidation, and Electrodisinfection

This work focuses on the application of electrolysis with carbon felt cathodes for the reclamation of actual effluents from municipal wastewater treatment facilities (WWTFs) in combination with different anode materials (dimensionally stable anodes-DSA, conductive diamond anodes-CDA and iron-Fe). First of all, the efficiency of electrodisinfection with CDA and DSA was assessed, finding that total elimination of Escherichia coli (E. coli) can be attained at applied electric charges below 0.03 Ah dm-3, and that the disinfection process is more efficient when using CDA. Furthermore, it was observed that the formation of hydrogen peroxide on carbon felt cathodes limits the concurrence of disinfection by-products (chlorates, perchlorates and organic chlorinated by-products), an interesting result that broadens the potential of CDA for the regeneration of urban wastewater. Results with Fe anodes show that it is possible to attain the complete removal of microorganisms with comparable efficiency to that of CDA (due to the contribution of Fenton's reaction) and that it was possible to totally remove the turbidity of the effluent when working at current densities from 12.50 A m-2. Finally, it was found that Fe is the most efficient anode material (lowest power consumption) at low current densities and CDA is the most appropriate one at current densities higher than 5 A m-2. According to these results, the pairs anode-cathode CDA-carbon felt and Fe-carbon felt behave as the most promising electrode materials to be applied in wastewater reclamation processes.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Sonochimie, Ultrasonic chemistry, Electrochimie, Electrochemistry, Cinétique, Kinetics, Cinética, Electrochimie, Electrochemistry, Electroquímica, Electrolyse, Electrolysis, Electrólisis, Ibuprofène, Ibuprofen, Ibuprofeno, Oxydation, Oxidation, Oxidación, Sonochimie, Sonochemistry, Sonoquímica, Sonolyse, Sonolysis, Sonólisis, Ultrason, Ultrasound, Ultrasonido, Pseudo first-order kinetics, and Sonoelectrolysis

A hybrid advanced oxidation process combining sonochemistry (US) and electrochemistry (EC) for the batch scale degradation of ibuprofen was developed. The performance of this hybrid reactor system was evaluated by quantifying on the degradation of ibuprofen under the variation in electrolytes, frequency, applied voltage, ultrasonic power density and temperature in aqueous solutions with a platinum electrode. Among the methods examined (US, EC and US/EC), the hybrid method US/EC resulted 89.32%, 81.85% and 88.7% degradations while using NaOH, H2SO4 and deionized water (DI), respectively, with a constant electrical voltages of 30 V, an ultrasound frequency of 1000 kHz, and a power density of 100 W L-1 at 298 K in 1 h. The degradation was established to follow pseudo first order kinetics. In addition, energy consumption and energy efficiencies were also calculated. The probable mechanism for the anodic oxidation of ibuprofen at a platinum electrode was also postulated.

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, Photoélectrochimie. Electrochimiluminescence, Photoelectrochemistry. Electrochemiluminescence, Antibiotique, Antibiotic, Antibiótico, Complexe de fer, Iron complex, Hierro complejo, Dégradation, Degradation, Degradación, Photoélectrochimie, Photoelectrochemistry, Fotoelectroquímica, Protection environnement, Environmental protection, Protección medio ambiente, pH, Ferricarboxylates, Near-neutral pH, Trimethoprim, and UV photoelectro-Fenton

A UVA photoelectro-Fenton (PEF) process mediated by Fe(III)-carboxylate complexes was applied to the removal of trimethoprim (TMP) antibiotic from water using a 2.2 L lab-scale flow plant equipped with a double compound parabolic collector (CPC) and an electrochemical cell composed of a boron-doped diamond (BDD) anode and a carbon-PTFE air-diffusion cathode. The presence of Fe(III)-carboxylate complexes enhances the regeneration of Fe3+ to Fe2+, allows to maintain iron in solution at higher pH values and can decrease the formation of Fe(III)-sulfate, Fe(III)-chloride and some Fe(III)-pollutants complexes. First, the efficiency of different carboxylate ligands like oxalate, citrate, tartrate and malate was assessed, followed by the application of various initial Fe(III)-to-carboxylate molar ratios and pH values. The PEF process with Fe(III)-oxalate, Fe(III)-citrate and Fe(III)-tartrate complexes revealed similar ability to degrade the antibiotic solution with the employment of 1:3,1:1 and 1:1 Fe(III)-to-carboxylate molar ratios, respectively, and using pH of 4.5, Fe3+ concentration of 2.0 mg L-1 (total iron emission limit for the discharge of treated effluents according to the Portuguese legislation), current density of 5 mA cm-2 and 20°C. The PEF process mediated by Fe(III)-malate complexes was much less effective. 1:6 and 1:9 Fe(III)- to-oxalate molar ratios were required to yield similar TMP removal kinetics at pH 5.0 and 5.5 compared to pH 4.5, respectively. Additionally, the influence of initial TMP content and solution temperature on the PEF process with Fe(III)-carboxylate complexes was assessed and the role of the different reactive oxidizing species was clarified by the addition of scavenging agents. Generated low-molecular-weight carboxylic acids were monitored by ion-exclusion HPLC.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Sonochimie, Ultrasonic chemistry, Electrochimie, Electrochemistry, Diamant, Diamond, Diamante, Eau usée, Waste water, Agua residual, Electrochimie, Electrochemistry, Electroquímica, Sonochimie, Sonochemistry, Sonoquímica, Ultrason, Ultrasound, Ultrasonido, Conductive diamond, Electrodisinfection, Integrated process, and Wastewater reclamation

In the present work. the disinfection of actual effluents from a municipal wastewater treatment plant (WWTP) by a conductive diamond sono-electrochemical process was assessed. First, efficiency of single electrodisinfection process with diamond anodes (without the contribution of ultrasounds) was studied, finding that the total disinfection can be attained at current charges applied below 0.02 kA h m-3. It was also found that the main disinfection mechanism is the attack of Escherichia coli (E. coli) by the disinfectants produced in the electrochemical cell and that the production of chlorates is avoided when working at current densities not higher than 1.27 A m-2. Next, a marked synergistic effect was found when coupling ultrasound (US) irradiation to the electrochemical system (sono-electrochemical disinfection). This increase in the disinfection rate was found to be related to the suppression of the agglomeration of E. coli cells and the enhancement in the production of disinfectant species.

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, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Electroénergétique, Electrical power engineering, Conversion directe et accumulation d'énergie, Direct energy conversion and energy accumulation, Conversion électrochimique: piles et accumulateurs électrochimiques, piles à combustibles, Electrochemical conversion: primary and secondary batteries, fuel cells, Energie, Energy, Energie. Utilisation thermique des combustibles, Energy. Thermal use of fuels, Appareils de production et de conversion d'énergie: énergie thermique, énergie électrique, énergie mécanique, etc, Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc, Piles à combustible, Fuel cells, Métal transition, Transition metal, Metal transición, Carbone, Carbon, Carbono, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Electrocatalyse, Electrocatalysis, Electrocatálisis, Electrochimie, Electrochemistry, Electroquímica, Nanoparticule, Nanoparticle, Nanopartícula, Nanotube carbone, Carbon nanotubes, Nanotube multifeuillet, Multiwalled nanotube, Nanotubo pared múltiple, Oxygène, Oxygen, Oxígeno, Pile combustible, Fuel cell, Pila combustión, Platine, Platinum, Platino, Protection environnement, Environmental protection, Protección medio ambiente, Réduction chimique, Chemical reduction, Reducción química, Stabilité, Stability, Estabilidad, Electrochemical stability, Oxygen reduction reaction, and Platinum nanoparticles

A non-covalent functionalization for multi-walled carbon nanotubes has been used as an alternative to the damaging acid treatment. Platinum nanoparticles with similar particle size distribution have been deposited on the surface modified multi-walled carbon nanotubes. The interaction between platinum nanoparticles and multi-walled carbon nanotubes functionalized with 1-pyrenecarboxylic acid is studied and its electrochemical stability investigated. This study reveals the existence of a platinum-support interaction and leads to three main conclusions. First, the addition of 1-pyrenecarboxylic acid is improving the dispersion of platinum nanoparticles, leading to an improved electrochemical activity towards oxygen reduction reaction. Second, the investigations regarding the electrochemical stability showed that the platinum-support interaction plays an important role in improving the long-term stability by as much as 20%. Third, post-mortem microscopy analysis showed a surprising effect. During the electrochemical stability investigations concerned with carbon corrosion it was found that the multi-walled carbon nanotubes were undergoing severe structural change, transforming finally into carbon spheres.

General chemistry, physical chemistry, Chimie générale, chimie physique, Energy, Énergie, Chemical engineering, Génie chimique, 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, Composé de métal de transition, Transition element compounds, Bactéricidie, Bactericidal effect, Bactericidia, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Oxyde de titane, Titanium oxide, Titanio óxido, Photocatalyse, Photocatalysis, Fotocatálisis, Protection environnement, Environmental protection, Protección medio ambiente, Rutile, Rutilo, Photoélectrocatalyse, Photoelectrocatalysis, (111} facets, Inactivation, and Rutile TiO2

This work reported the use of a UV and visible light active rutile TiO2 photoanode with 100% exposed {111} faceted surface for photocatalytic and photoelectrocatalytic bactericidal applications. The bactericidal performances of the photoanode with UV and visible light driven photocatalysis and photoelectrocatalysis processes were evaluated using Escherichia coli as the test bacteria. Under the UV irradiation, 99.97% inactivation of 45 mL of 1.0 × 107 CFU/mL E. coli cells can be achieved within 10min for photoelectrocatalysis treatment, while only 96.40% inactivation can be obtained within 30min for photocatalysis treatment. Under the visible light irritation, 88.46% inactivation can be achieved with 180 min photocatalytic treatment, while 100% inactivation by photoelectrocatalytic treatment can be achieved over the same period. The bactericidal performance of the rutile TiO2 film was also evaluated for sunlight driven photocatalysis treatment. 1.0 mL of 1.0 × 107 CFU/mL E. coli cells can be completely inactivated within 2.0 min. The rutile TiO2 film photocatalyst can be used for 20 consecutive bactericidal experiments without the noticeable change in bactericidal performance.

General chemistry, physical chemistry, Chimie générale, chimie physique, Energy, Énergie, Chemical engineering, Génie chimique, 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, Complexe de métal de transition, Transition element complexes, Complexe de rhénium, Rhenium complex, Renio complejo, Dioxyde de carbone, Carbon dioxide, Carbono dióxido, Electrochimie, Electrochemistry, Electroquímica, Photocatalyse, Photocatalysis, Fotocatálisis, Photochimie, Photochemistry, Fotoquímica, Réaction catalytique, Catalytic reaction, Reacción catalítica, Réduction chimique, Chemical reduction, Reducción química, BODIPY, Catalysis, and Rhenium bipyridine derivatives

The reduction of carbon dioxide to chemical fuels such as carbon monoxide is an important challenge in the field of renewable energy conversion. Given the thermodynamic stability of carbon dioxide, it is difficult to efficiently activate this substrate in a selective fashion and the development of new electrocatalysts for CO2 reduction is of prime importance. To this end, we have prepared and studied a new fac-Re1(CO)3 complex supported by a bipyridine ligand containing ancillary BODIPY moieties ([Re(BB2)(CO)3Cl]). Voltammetry experiments revealed that this system displays a rich redox chemistry under N2, as [Re(BB2)(CO)3Cl] can be reduced by up to four electrons at modest potentials. These redox events have been characterized as the Rel/0 couple, and three ligand based reductions ― two of which are localized on the BODIPY units. The ability of the BB2 ligand to serve as a non-innocent redox reservoir is manifest in an enhanced electrocatalysis with CO2 as compared to an unsubstituted Re-bipyridine complex lacking BODIPY units ([Re(bpy)(CO)3Cl]). The second order rate constant for reduction of CO2 by [Re(BB2)(CO)3Cl] was measured to be k = 3400 M-1 S-1 at an applied potential of ―2.0 V versus SCE, which is roughly three times greater than the corresponding unsubstituted Re-bipyridine homologue. Photophysical and photochemical studies were also carried out to determine if [Re(BB2)(CO)3Cl] was a competent platform for CO2 reduction using visible light. These experiments showed that this complex supports unusual excited state dynamics that precludes efficient CO2 reduction and are distinct from those that are typically observed for fac-Re1(CO)3 complexes.

General chemistry, physical chemistry, Chimie générale, chimie physique, Energy, Énergie, Chemical engineering, Génie chimique, 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, Etat colloïdal et états dispersés, Colloidal state and disperse state, Matériaux poreux, Porous materials, Composé de métal de transition, Transition element compounds, Anatase, Anatasa, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Conductivité électrique, Electrical conductivity, Conductividad eléctrica, Film, Película, Matériau poreux, Porous material, Material poroso, Microstructure, Microestructura, Mésoporosité, Mesoporosity, Mesoporosidad, Nanocomposite, Nanocompuesto, Oxyde de titane, Titanium oxide, Titanio óxido, Photocatalyse, Photocatalysis, Fotocatálisis, Photoélectrochimie, Photoelectrochemistry, Fotoelectroquímica, Polymère, Polymer, Polímero, Pore, Poro, Rutile, Rutilo, Agent structurant, Template, Dissociation de l'eau, Water splitting, and Mesoporous

We describe the polymer templating of inorganic sol-gel precursors for making thermally stable mesoporous anatase-rutile TiO2:Ta nanocomposite films with high surface area (SBET ≥ 150m2g-1). Mesostructured films with cubic pore symmetry and pore sizes ranging from 17 nm to 26 nm in diameter were prepared from different diblock copolymers such as polyisobutylene-block-poly(ethylene oxide) and were characterized by various microscopy techniques, grazing incidence small-angle X-ray scattering, X-ray diffraction and Rietveld refinement, X-ray photoelectron spectroscopy, and impedance spectroscopy. Here, we specifically focus on the material with the smaller pores. Our research data establish that (1) the nanoscale structure can be preserved up to 900 C, (2) anatase is the primary phase, (3) the phase composition remains constant over a broad temperature range, (4) anatase-to-rutile transformation and formation of L-Ta2O5 do not occur below 800 C, and that (5) the films contain a non-negligible fraction of Ti3+ species. The latter results in a room-temperature electrical conductivity (~2.4mScm-1) much higher than that reported for stoichiometric TiO2. Compositionally, the material can be described by the chemical formula Ta0.24Ti0.75O2±δ. The mesoporous nanocomposite films (Eg≈3.4eV) also display interesting photocatalytic properties and photoelectrochemical activity which makes them interesting for different applications such as wastewater detoxification.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Electrochimie, Electrochemistry, Photoélectrochimie. Electrochimiluminescence, Photoelectrochemistry. Electrochemiluminescence, Etat colloïdal et états dispersés, Colloidal state and disperse state, Etudes physiques et chimiques. Granulométrie. Phénomènes électrocinétiques, Physical and chemical studies. Granulometry. Electrokinetic phenomena, Sciences appliquees, Applied sciences, Energie, Energy, Energie naturelle, Natural energy, Energie solaire, Solar energy, Conversion photovoltaïque, Photovoltaic conversion, Cellules solaires. Cellules photoélectrochimiques, Solar cells. Photoelectrochemical cells, Composé binaire, Binary compound, Compuesto binario, Composé de métal de transition, Transition element compounds, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur, Catalyst, Catalizador, Cellule photoélectrochimique, Photoelectrochemical cell, Célula fotoelectroquímica, Colorant, Dyes, Colorante, Fluorescence, Fluorescencia, Manganèse II, Manganese II, Manganeso II, Nanoparticule, Nanoparticle, Nanopartícula, Oxydation, Oxidation, Oxidación, Oxyde de titane, Titanium oxide, Titanio óxido, Photoélectrochimie, Photoelectrochemistry, Fotoelectroquímica, TiO2, Dye-sensitized photoelectrochemical cell, Photoanode, and Turn-on fluorescence

A manganese complex covalently attached to a TiO2 electrode via a light-absorbing organic linker (L) was used in the photooxidation of 2',7'-dihydrodichlorofluorescein (H2DCF). Significant and sustained photocurrent was observed upon visible-light illumination of the fully assembled anode in the presence of the substrate. The two-electron, two-proton oxidation of H2DCF yields the fluorescent compound, 2',7'-dichlorofluorescein (DCF). Our studies suggest that the MnII-L-TiO2 architecture is an effective photoanode for multielectron chemistry, as production of DCF under visible-light illumination exceeds yields observed for bare TiO2 as well as ZnII-L-TiO2 anodes. The turn-on fluorescent behavior of H2DCF upon oxidation makes it an excellent substrate for the study of new photoanodes. The high fluorescence quantum yield of DCF allows for nanomolar sensitivity and real-time monitoring of substrate oxidation.

General chemistry, physical chemistry, Chimie générale, chimie physique, Energy, Énergie, Chemical engineering, Génie chimique, 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, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Electroénergétique, Electrical power engineering, Conversion directe et accumulation d'énergie, Direct energy conversion and energy accumulation, Conversion électrochimique: piles et accumulateurs électrochimiques, piles à combustibles, Electrochemical conversion: primary and secondary batteries, fuel cells, Energie, Energy, Energie. Utilisation thermique des combustibles, Energy. Thermal use of fuels, Appareils de production et de conversion d'énergie: énergie thermique, énergie électrique, énergie mécanique, etc, Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc, Piles à combustible, Fuel cells, Article synthèse, Review, Artículo síntesis, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Catalyseur, Catalyst, Catalizador, Electrochimie, Electrochemistry, Electroquímica, Electrode, Electrodes, Electrodo, Pile combustible, Fuel cell, Pila combustión, Protection environnement, Environmental protection, Protección medio ambiente, Réduction chimique, Chemical reduction, Reducción química, Technologie bas carbone, CO2 reduction, Fuel cells, Metal electrodes, and Molecular catalysts

In this review article, we report the development and utilisation of fuel cells, metal electrodes in aqueous electrolyte and molecular catalysts in the electrochemical reduction of CO2. Fuel cells are able to function in both electrolyser and fuel cell mode and could potentially reduce CO2 and produce energy at the same time. However, it requires considerably high temperatures for efficient operation. Direct reduction using metal electrodes and molecular catalysts are possible at room temperatures but require an additional applied potential and generally have low current densities. Density functional theory (DFT) studies have been used and have begun to unveil possible mechanisms involved which could lead to improvements and development of more efficient catalysts.

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, Métal transition, Transition metal, Metal transición, Activation, Activación, Carbonate de sodium, Sodium carbonate, Sodio carbonato, Carbure, Carbides, Carburo, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Electrocatalyse, Electrocatalysis, Electrocatálisis, Hyperfréquence, Microwave, Hiperfrecuencia, Oxygène, Oxygen, Oxígeno, Protection environnement, Environmental protection, Protección medio ambiente, Réduction chimique, Chemical reduction, Reducción química, Zirconium, Zirconio, Activated ZrC, Microwave method, Oxygen reduction, and Sodium carbonate activation

The activated porous zirconium carbide (ZrC) is prepared by sodium carbonate activation of commercial ZrC. As a result of sodium carbonate activation, there is a tremendous increase in the surface area (from 0.6 to 96 m2 g―1) and chemisorption capability of commercial ZrC. This ZrC is incorporated into Vulcan carbon XC-72R by solid-state reaction using intermittent microwave heating (IMH) method, and Pt nanoparticles were dispersed by microwave-assisted polyol process. The electrocatalyst samples were characterized by PXRD, BET, SEM, TEM, XPS and their performance for oxygen reduction reaction was studied in 0.1 mol L―1 HClO4 aqueous electrolyte by cyclic voltammetry and rotating ring disk electrode. The XRD, XPS and TEM results indicate well dispersed ZrC and Pt nanoparticles over Vulcan carbon XC-72R. When the activated ZrC combined with platinum, the resulting composite electrocatalyst showed higher activity for oxygen reduction which exceeds that of the commercial Pt/C catalyst of similar metal loading. Our approach shows that sodium carbonate activation is an effective method for the activation of metal carbides, which is essential for tuning the microstructural properties of electrocatalyst support.

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, Sciences appliquees, Applied sciences, Electrotechnique. Electroenergetique, Electrical engineering. Electrical power engineering, Electroénergétique, Electrical power engineering, Conversion directe et accumulation d'énergie, Direct energy conversion and energy accumulation, Conversion électrochimique: piles et accumulateurs électrochimiques, piles à combustibles, Electrochemical conversion: primary and secondary batteries, fuel cells, Energie, Energy, Energie. Utilisation thermique des combustibles, Energy. Thermal use of fuels, Appareils de production et de conversion d'énergie: énergie thermique, énergie électrique, énergie mécanique, etc, Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc, Piles à combustible, Fuel cells, Composé binaire, Binary compound, Compuesto binario, Métal transition, Transition metal, Metal transición, Antimoine, Antimony, Antimonio, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Electrocatalyse, Electrocatalysis, Electrocatálisis, Oxyde d'antimoine, Antimony oxide, Antimonio óxido, Oxyde d'étain, Tin oxide, Estaño óxido, Oxygène, Oxygen, Oxígeno, Pile combustible, Fuel cell, Pila combustión, Platine, Platinum, Platino, Protection environnement, Environmental protection, Protección medio ambiente, Réduction chimique, Chemical reduction, Reducción química, Support, Soporte, O Sn, SnO2, Antimony doped tin oxides, Fuel cells, and Oxygen reduction reactions

Alternative composite supports for platinum catalysts were synthesized from antimony doped tin dioxide (ATO) nanoparticles. In the range of the antimony content from 0 to 11 mol%, the highest electrical conductivity of 1.1 S cm―1 at 130°C was obtained for the 5 mol% Sb ATO, from which composite supports composed of oxides and carbon and supported platinum catalysts were prepared. Using the pure oxide support, the Pt/ATO catalyst displayed superior specific activity and stability for the oxygen reduction reactions (ORRs). Low surface area of ATO caused poor dispersion of Pt particles compared to composite supports, which limited the mass activity of the supported catalysts. When the ATO composites were used as supports, the Pt/C-ATO catalysts showed significantly enhanced catalytic activity and durability for the ORR, attributable to the high ECSA and modified electronic structure of Pt by the ATO phase in the catalyst support.