Increasing visible-light absorption for photocatalysis with black BiOCl

Black BiOCl with oxygen vacancies was prepared by UV light irradiation with Ar blowing. The as-prepared black BiOCl sample showed 20 times higher visible light photocatalytic activity than white BiOCl for RhB degradation. The trapping experiment showed that the superoxide radical (O-2(center dot-)) and holes (h(+)) were the main active species in aqueous solution under visible light irradiation.