Methanol electrooxidation on carbon-supported Pt-WO3?x electrodes in sulphuric acid electrolyte

Sterilization of Escherichia coli by Photothermal Synergy of WO3-x/C Nanosheet under Infrared Light Irradiation

The application of photocatalytic sterilization technology for the sterilization of water has been broadly studied in recent years. However, developing photocatalysts with high disinfection efficiency remains an urgent challenge. Tungsten trioxide with coexisting oxygen vacancies and carbon coating (WO_3-x/C) has been successfully synthesized toward the photothermal inactivation of Escherichia coli. Oxygen vacancies and carbon coating bring WO_3-x/C strong absorption in the infrared region and enhance the carrier separation efficiency. As a result, a higher sterilization rate is obtained compared to WO₃. WO_3-x/C can completely inactivate E. coli under infrared light within 40 min through photothermal synergy process. During the process of inactivating bacteria over WO_3-x/C, E. coli is killed by the destruction of their cell membrane to decrease the activity of enzymes and release the cell contents, which can be ascribed to the efficient generation of reactive oxygen species (O₂^•- and ^•OH) and thermal effect. This work demonstrates a novel approach for engineering efficient and energy-saving catalysts for water sterilization.

Properties, fabrication and applications of plasmonic semiconductor nanocrystals

We highlight three widely explored oxide-based plasmonic materials, including H_xMoO_3−y, H_xWO_3−y, and Mo_xW_1−xO_3−y, and their applications in catalysis.

Electrochemical properties of mixed WC and Pt-black powders

The electrochemical characteristics of a mixture of Pt-black and WC powders and its catalytic activity for methanol and formic acid oxidation were investigated in acid solution. XRD and AFM measurements revealed that the WC powder employed for the investigation was a single-phase material consisting of crystallites/spherical particles of average size of about 50 nm, which were agglomerated into much larger particles. Cyclic voltammetry showed that the WC underwent electrochemical oxidation, producing tungstate species. In the case of the mixed Pt + WC powders, the tungstate species were deposited on the Pt as a thin film of hydrous tungsten oxide. Enhanced hydrogen intercalation in the hydrous tungsten oxide was observed and it was proposed to be promoted in mixed powders by the presence of hydrogen adatoms on bare Pt sites. The determination of Pt surface area in the Pt + WC layer by stripping of underpotentially deposited Cu revealed that the entire Pt surface was accessible for underpotential deposition of Cu. Investigation of the electrochemical oxidation of methanol and formic acid on Pt + WC and pure Pt layers did not indicate electrocatalytic promotion due to the presence of WC.

Synthesis and Characterization of Pt−WO3 as Methanol Oxidation Catalysts for Fuel Cells

Several compositions of Pt-WO3 catalysts were synthesized and characterized for the electro-oxidation of methanol and CO. The surface morphologies of the catalysts were found to be dependent on the composition. X-ray energy dispersive spectroscopy and X-ray photoelectron spectroscopy results suggest a surface enrichment of WO3 in the codeposited Pt-WO3 catalysts. Cyclic voltammetry and chronoamperometry in methanol show an improvement in catalytic activity for the Pt-WO3 catalysts. A significant improvement in the poison tolerance toward CO and other organic intermediates was observed in the mixed metal-metal oxide catalyst. The catalytic performance of the different compositions was directly compared by normalization of the current to active sites. CO-stripping voltammetry suggests the involvement of WO3 in the catalytic process as opposed to a mere physical effect as suggested by previous work. A possible mechanism for this improvement is proposed based on the electrochemical data.

Oxidação eletroquímica do metanol sobre partículas de PtRu e PtMo suportadas em carbono de alta área superficial

A reação de eletro-oxidação do metanol foi estudada sobre eletrocatalisadores de Pt/C, PtRu/C e PtMo/C preparados pelo método do ácido fórmico em diferentes composições atômicas. Os produtos da oxidação do metanol foram monitorados pela técnica de DEMS. O desempenho dos catalisadores frente a reação de oxidação do metanol foi estudado através dos perfis voltamétricos e experimentos de cronoamperoometria.