Methane conversion and hydrogen production over TiO2/WO3/Pt heterojunction photocatalysts

Abstract

Along with the advantages of mild reaction conditions, simple operation, and low energy consumption, the photocatalytic conversion of methane in the presence of water presents great potential in facilitating direct methane conversion into value-added chemicals and H₂ generation. In this work, TiO₂/WO₃ heterojunction photocatalysts modified with Pt nanoparticles were synthesized and their performances towards methane conversion into ethane (C₂H₆) and hydrogen (H₂) in the presence of water were evaluated. The ternary photocatalysts were characterized by X-ray diffraction, UV-vis, scanning and transmission electron microscopy and X-ray photoelectron spectroscopy. The highly active TiO₂/WO₃/Pt photocatalyst achieved C₂H₆ and H₂ production rates of 1.18 mmol g⁻¹ h⁻¹ and 57 mmol g⁻¹ h⁻¹, respectively. These values were 37% (for C₂H₆) and 34% (for H₂) higher than those produced by a TiO₂/Pt photocatalyst. The results show that the presence of WO₃ in a very small concentration on TiO₂ with the introduction of Pt as a co-catalyst contributes to achieving higher activities towards both C₂H₆ and H₂ evolution.