Infrared radiation active, novel nanocomposite photocatalyst for water splitting

•An IR active TiO2/Ag2O composite photocatalyst was prepared.•The composite catalyst was active in catalytic H2O reduction of water under IR light.•The H2 evolution of 25.64 ml h−1 g−1 was achieved under IR light.•A mulitiphoton, sub-band gap excitation mechanism is proposed.

In this report, we investigated an infrared photon active catalytic system for the conversion of solar energy into chemical energy in which we introduced an effective “Dark Photocatalyst” for photolysis of water. The Ag2O/TiO2 composite catalyst containing 28% of silver and 72% of titanium was synthesised by a simple chemical deposition method. The catalyst was found to be active in the infrared region of the solar spectrum or in the dark and hydrogen production was demonstrated for the first using low-energy 800–1200 nm IR radiation. Sub-band gap phonon assisted multi-photon excitation is proposed for the observed infrared photocatalytic activity of Ag2O/TiO2 composite.