Ammonia-dependent synthesis of (BiO)2OHCl@Bi24O31Cl10 heterostructures with enhanced visible-light induced photocatalytic activities on levofloxacin removal

Abstract

Designing semiconductor photocatalyst with high visible-light sensitivity and good photocatalytic performance is still a key issue for pollutant remediation and energy storage. In this work, a series of (BiO)2OHCl@Bi24O31Cl10 composite photocatalysts were synthesized through an ammonia-dependent aqueous strategy with (BiO)2OHCl as the in-situ formed precursor. More ammonia introduction in the synthetic system led to faster transformation of (BiO)2OHCl to Bi24O31Cl10 component and resulted in composites with controllable compositions. The Bi-based heterostructures extended good visible-light absorption ability and strengthened internal electric field (IEF) to induce the generation of charge carriers and promote bulk-charge separation (BCS) efficiency for antibiotic removal. (BiO)2OHCl@Bi24O31Cl10 composites with optimum compositions exhibited superior photocatalytic activities on levofloxacin (LEV) degradation under visible-light irradiation, roughly two times higher than that of individual (BiO)2OHCl or Bi24O31Cl10 powders. The high degradation efficiency and rapid reaction kinetics would be ascribed to the valid charge transfer from the bulk interior to the surface of composite catalysts. The sheet-like Bi24O31Cl10 at catalyst surface and matched band structures of two components in (BiO)2OHCl@Bi24O31Cl10 heterostructures are also proposed as vital factors to influence the photocatalytic performances. This study hopes to provide new insights for the design of visible-light induced bismuth-based photocatalysts for practical applications.