2D/2D Bi-MOF-derived BiOCl/MoS2 nanosheets S-scheme heterojunction for effective photocatalytic degradation

Abstract

Constructing S-scheme heterojunction derived from metal-organic frameworks (MOFs) with high photoredox ability and boosted charge separation efficiency is promising in photocatalytic wastewater treatment. Herein, the MOF-BiOCl composite composed of BiOCl nanosheets and rod-like Bismuth-MOF (CAU-17) as the bismuth source precursor was prepared in situ via a halogenation process. Rational coupling the MOF-BiOCl with MoS2 nanosheets, an S-scheme heterojunction with enhanced photocatalytic tetracycline (TC) degradation efficiency was constructed. The optimized MOF-BiOCl/MoS2-3 composite exhibited the highest TC degradation rate (90% in 20 min). The improvement of photocatalytic degradation is mainly due to i) in situ synthesis of BiOCl nanosheets derived from Bismuth-MOFs avoided the aggregation of individual BiOCl nanosheets and preserved the ultrahigh porosity and specific surface area of the MOFs which generated more adsorption sites; ii) driven by the formed internal electric field, the charges followed an S-scheme transfer rout which retained the highest redox potential; iii) the 2D/2D BiOCl/MoS2 nanosheets geometry provided more intimate interfacial contacts which accelerate the charge separation and migration. This work offers an ideal strategy for constructing the effective heterostructure photocatalyst in the photocatalytic wastewater treatment.