Visible-light-driven generation of chlorine with powdered WO3 in aqueous solution via redox catalysis

Abstract

This study reports the generation of Cl₂ when aqueous dispersions of WO₃ solutions of NaCl are irradiated in the visible. The rate of Cl₂ evolution is dependent on the amount of catalyst, pH of solution, concentration of NaCl used, intensity of light and concentration of the oxidant (O₂) present. WO₃ is also photoactive in LiCl solutions and O₂ reduction was also observed in this case. Light promotes the transfer of an electron from Cl^– to O₂ in a reaction that is thermodynamically uphill.