The mechanism and material aspects of a novel Ag2O/TiO2 photocatalyst active in infrared radiation for water splitting

The Ag2O/TiO2 catalyst produces hydrogen with water and water/methanol mixture upon irradiation with IR light. In this report, the material aspects and photocatalytic mechanism of an IR-active Ag2O/TiO2 photocatalyst for water splitting reaction were investigated. The Ag2O/TiO2 catalyst contained 28% silver and 72% titanium by w/w and the XPS and XRD results revealed the presence of Ag2O (Ag+), Ago, TiO2 (Ti4+) and Ti3+ states in the Ag2O/TiO2 catalyst. A solid proof of the IR photon-initiated catalytic activity of the Ag2O/TiO2 catalyst was observed from the clear and enhanced IR response in the incident photon current conversion efficiency measurements of the Ag2O/TiO2 catalyst. Comparing the band gap energies to the energy of the IR source, plasmon-assisted photocatalytic activity and/or sub-band gap phononassisted multi-photon excitation mechanisms are proposed for the observed infrared photocatalytic activity of the Ag2O/TiO2 photocatalyst and the functions of Ag2O and TiO2 in dark photocatalysis are discussed.