Simultaneous hydrogen production and decomposition of H₂ S dissolved in alkaline water over CdS - TiO₂ composite photocatalysts under visible light irradiation

A process of simultaneous hydrogen production and H₂ S removal has been investigated over a highly active composite photocatalyst made of bulk CdS decorated with nanoparticles of TiO₂, i.e. CdS(bulk)/TiO₂. The photocatalytic activity was evaluated for hydrogen production from aqueous electrolyte solution containing H₂ S dissolved in water or alkaline solution under visible light irradiation. The rate of hydrogen production from the H₂ S-containing alkaline solution was similar to the rate obtained from photocatalytic hydrogen production from water containing sacrificial reagents (Na₂ S + Na₂ SO₃) in the similar concentration. The isotope experiment was carried out with D₂ O instead of H₂ O to investigate the source of hydrogen from photocatalytic decomposition of H₂ S dissolved in H₂ O or alkali solution under visible light. Hydrogen originated from both H₂ S and H₂ O when the reaction solution contained H₂ S absorbed in alkaline water.