Bi4O5Br2-based binary composites: Facile fabrication, characterization, and enhanced photocatalytic performance over NO removal

NOx at ppb level in atmospheric environment should be rationally treated through a suitable and efficient photocatalytic system. In the current study, oxygen-enriched oxybromide Bi4O5Br2 was modified with various amount of graphite graphene oxide via a facile in-situ precipitation route and resultant composites were systematically characterized by a series of analyses. The addition of graphite graphene oxide induced relatively small-sized Bi4O5Br2 nanosheets, thus causing expansion of band structures with stronger redox capabilities. In addition, the involvement of graphene oxide in composites also leaded to enlarged specific surfaces areas with abundant active sites, enhanced visible light harvesting, and strengthened charge carriers by heterojunction domains at interface, ensuring the improved photocatalytic NO removal efficiencies in comparison to bare Bi4O5Br2 under visible light. Moreover, the generation of toxic intermediate NO2 was obviously constrained. Eventually, these robust binary composites exhibited strong structural-stability and satisfactory reusability and a probable photocatalysis mechanism was speculated basing upon entrapping experiments and ESR results.

Automated summary

In this study, oxygen-enriched oxybromide Bi4O5Br2 was modified with varying amounts of graphite graphene oxide via a facile in-situ precipitation route, resulting in nanosheets with expanded band structures and enhanced redox capabilities. The addition of graphene oxide led to increased specific surface areas with abundant active sites, improved visible light harvesting, and strengthened charge carriers at heterojunction domains, resulting in higher photocatalytic NO removal efficiencies under visible light. The binary composites also exhibited strong structural stability, satisfactory reusability, and constrained generation of toxic intermediate NO2.