Novel S-scheme 2D/2D Bi4O5Br2 nanoplatelets/g-C3N5 heterojunctions with enhanced photocatalytic activity towards organic pollutants removal

Removal of organic pollutants and pharma products in waste water using semiconductor photocatalysts has gained huge interest among recent days. However, low visible light absorption, recombination rate of charge carriers and less availability of reaction sites are still major obstacles for the photocatalysis process. Herein, an in situ-forming Bi4O5Br2 nanosheets decorated on the surface g-C3N5 were prepared via simple hydrothermal method under ambient temperature. The basic pH condition plays a vital role in growing for Bi4O5Br2 nanosheets. Various characterization studies such as TEM, SEM, PL and UV-DRS studies confirmed the formation of close contact between the Bi4O5Br2 and g-C3N5 nanosheets. The construction of Bi4O5Br2 nanoplatelets/g-C3N5 nanocomposite increases the surface-active sites and improving the separation efficiencies of excitons, which is greatly influenced in the degradation of ciprofloxacin and bisphenol-A pollutants. Meanwhile, the flow of electrons from the layered structured graphite carbon of g-C3N5 which enables excellent electrical contact in the heterojunction. Besides, the main free radicals were determined as e and center dot O2, and production level of free radicals were confirmed by radical trapping experiments. The possible degradation mechanism was proposed and discussed. Finally, this work provides a unique approach to in-situ preparation of heterojunction photocatalysts and demonstrates the prepared Bi4O5Br2 nanoplatelets/g-C3N5 photocatalysts have great potential in the waste water management.

Automated summary

The use of semiconductor photocatalysts for the removal of organic pollutants and pharma products in waste water has gained significant interest. However, challenges such as low visible light absorption, recombination rate of charge carriers, and scarcity of reaction sites still hinder the photocatalysis process. In this study, in situ-forming Bi4O5Br2 nanosheets decorated with g-C3N5 were prepared using a simple hydrothermal method. The construction of this nanocomposite increased surface-active sites and improved the separation efficiencies of excitons, leading to enhanced degradation of ciprofloxacin and bisphenol-A pollutants. The prepared Bi4O5Br2/g-C3N5 photocatalysts also showed excellent electrical contact in the heterojunction, enabling efficient electron flow. This work provides a unique approach to the preparation of heterojunction photocatalysts and showcases their potential in waste water management.