Phototransformations of TiO(2)/Ag(2)O composites and their influence on photocatalytic water splitting accompanied by methanol photoreforming

This work aimed to revise the mechanism of photocatalytic activity of the TiO(2)/Ag(2)O system in photocatalytic water splitting accompanied by methanol photoreforming. The transformation of Ag(2)O into silver nanoparticles (AgNPs) during photocatalytic water splitting/methanol photoreforming was monitored using XRD, XPS, SEM, UV-vis, and DRS techniques. The impact of AgNPs, grown on TiO(2), on its optoelectronic properties was analysed through inter alia spectroelectrochemical measurements. The photoreduced material exhibited a significantly shifted position of the TiO(2) conduction band edge. Surface photovoltage measurements revealed the lack of photoinduced exchange of electrons between TiO(2) and Ag(2)O, indicating the absence of an efficient p–n junction. Furthermore, the impact of chemical and structural changes in the photocatalytic system on the production of CO and CO(2) from methanol photoreforming was analysed. It was found that fully formed AgNPs exhibit improved efficiency in the production of H(2), whereas the Ag(2)O phototransformation, resulting in the growth of AgNPs, promotes simultaneously ongoing photoreforming of methanol.