Methanol oxidation and photo-oxidation at Pt/WO3 electrocatalysts on graphite substrates

A composite approach to synthesize a high-performance Pt/WO3–carbon catalyst for optical and electrocatalytic applications

Optical and electrocatalytic activity of the synthesized Pt/WO3–C nanocomposite in acidic and alkaline media.

Tungsten-Based Catalysts for Environmental Applications

This review aims to give a general overview of the recent use of tungsten-based catalysts for wide environmental applications, with first some useful background information about tungsten oxides. Tungsten oxide materials exhibit suitable behaviors for surface reactions and catalysis such as acidic properties (mainly Brønsted sites), redox and adsorption properties (due to the presence of oxygen vacancies) and a photostimulation response under visible light (2.6–2.8 eV bandgap). Depending on the operating condition of the catalytic process, each of these behaviors is tunable by controlling structure and morphology (e.g., nanoplates, nanosheets, nanorods, nanowires, nanomesh, microflowers, hollow nanospheres) and/or interactions with other compounds such as conductors (carbon), semiconductors or other oxides (e.g., TiO2) and precious metals. WOx particles can be also dispersed on high specific surface area supports. Based on these behaviors, WO3-based catalysts were developed for numerous environmental applications. This review is divided into five main parts: structure of tungsten-based catalysts, acidity of supported tungsten oxide catalysts, WO3 catalysts for DeNOx applications, total oxidation of volatile organic compounds in gas phase and gas sensors and pollutant remediation in liquid phase (photocatalysis).

Ta3N5/Co(OH)x composites as photocatalysts for photoelectrochemical water splitting

Ta3N5 nanotubes (NTs) were obtained from nitridation of Ta2O5 NTs, which were grown directly on Ta foil through a 2-step anodization procedure. With Co(OH)x decoration, a photocurrent density as high as 2.3 mA cm-2 (1.23 V vs. NHE) was reached under AM1.5G simulated solar light; however, the electrode suffered from photocorrosion. More stable photoelectrochemical (PEC) performance was achieved by first loading Co(OH)x, followed by loading cobalt phosphate (Co-Pi) as double co-catalysts. The Co(OH)x/Co-Pi double co-catalysts may act as a hole storage layer that slows down the photocorrosion caused by the accumulated holes on the surface of the electrode. A "waggling" appearance close to the "mouth" of Ta2O5 NTs was observed, and may indicate structural instability of the "mouth" region, which breaks into segments after nitridation and forms a top layer of broken Ta3N5 NTs. A unique mesoporous structure of the walls of the Ta3N5 NTs, which is reported here the first time, is also a result of the nitridation process. We believe that the mesoporous structure makes it difficult for the nanotubes to be fully covered by the co-catalyst layer, hence rationalizing the remaining degradation by photocorrosion.

Facile synthesis of Pt nanoparticles supported on anatase TiO2 nanotubes with good photo-electrocatalysis performance for methanol

A Pt/TNTs/C catalyst showed enhanced MOR performance under the light illumination.

TiO2 Nanotube-Carbon (TNT-C) as Support for Pt-based Catalyst for High Methanol Oxidation Reaction in Direct Methanol Fuel Cell

In this study, TiO₂ nanotubes (TNTs) were synthesized via a hydrothermal method using highly concentrated NaOH solutions varying from 6 to 12 M at 180 °C for 48 h. The effects of the NaOH concentration and the TNT crystal structure on the performance for methanol oxidation were investigated to determine the best catalyst support for Pt-based catalysts. The results showed that TNTs produced with 10 M NaOH exhibited a length and a diameter of 550 and 70 nm, respectively; these TNTs showed the best nanotube structure and were further used as catalyst supports for a Pt-based catalyst in a direct methanol fuel cell. The synthesized TNT and Pt-based catalysts were analysed by FESEM, TEM, BET, EDX, XRD and FTIR. The electrochemical performance of the catalysts was investigated using cyclic voltammetry (CV) and chronoamperometric (CA) analysis to further understand the methanol oxidation in the direct methanol fuel cell (DMFC). Finally, the result proves that Pt-Ru/TNT-C catalyst shows high performance in methanol oxidation as the highest current density achieved at 3.3 mA/cm² (normalised by electrochemically active surface area) and high catalyst tolerance towards poisoning species was established.

Tin dioxide facilitated truncated octahedral Pt3Ni alloy catalyst: synthesis and ultra highly active and durable electrocatalysts for oxygen reduction reaction

This work firstly synthesized SnO₂ modified truncated octahedral Pt₃Ni alloy nanoparticle electrocatalyst using neat FPD as the solvent, ORR activity and durability of which is 2.4 times and 2.5 times that of Pt₃Ni catalysts.

Visible light assisted electro–photo synergistic catalysis of heterostructured Pd–Ag NPs/graphene for methanol oxidation

Heterostructured Pd-Ag/GNs catalytic performances for MOR are significantly improved by visible light irradiation: (a) without irradiation, (b) under irradiation.

Photocatalytic oxidation of methanol using porous Au/WO3 and visible light

Porous WO₃ and Au/WO₃ were used as new visible light photocatalysts for the oxidation of MeOH.