Defect-triggered catalysis with multiple reactive species over bismuth oxyhalides in the dark

Abstract

Semiconductor photocatalysis suffers from geographical and temporal limitations. Here, BiOBrxI1-x solid solutions with oxygen vacancies (OVs) prepared by facile direct-precipitation are applied as efficient catalysts without light. The rapid crystallization process enables OVs easily to be formed in BiOBrxI1-x, and the OVs concentration is well-modulated by controlling the solvent type and solid solution composition. All BiOBrxI1-x demonstrate OVs-triggered catalytic performance for degrading tetracycline hydrochloride and killing Escherichia coli in the dark. BiOBr0.93I0.07 prepared in ethylene glycol exhibits the most prominent catalytic activity, which is attributed to the suitable OVs concentration and favorable band structure that benefit the generation of multiple reactive species (superoxide radicals, holes and hydroxyl radicals) and promoting the charge separation. Additionally, OVs depleted after a long period of time can be in-situ regenerated for sustained long term catalysis by irradiating the catalysts with UV light. This work is expected to facilitate the development of defect-activated catalytic reaction in the dark.