Simultaneous hydrogen production and decomposition of dissolved in alkaline water over composite photocatalysts under visible light irradiation

A process of simultaneous hydrogen production and H 2 S removal has been investigated over a highly active composite photocatalyst made of bulk CdS decorated with nanoparticles of TiO 2 , i.e. CdS(bulk)/ TiO 2 . The photocatalytic activity was evaluated for hydrogen production from aqueous electrolyte solution containing H 2 S dissolved in water or alkaline solution under visible light irradiation. The rate of hydrogen production from the H 2 S -containing alkaline solution was similar to the rate obtained from photocatalytic hydrogen production from water containing sacrificial reagents ( Na 2 S + Na 2 SO 3 ) in the similar concentration. The isotope experiment was carried out with D 2 O instead of H 2 O to investigate the source of hydrogen from photocatalytic decomposition of H 2 S dissolved in H 2 O or alkali solution under visible light. Hydrogen originated from both H 2 S and H 2 O when the reaction solution contained H 2 S absorbed in alkaline water.