Interface engineering of p-p Z-scheme BiOBr/Bi12O17Br2 for sulfamethoxazole photocatalytic degradation

The Z-scheme heterojunction has received widespread attention due to it can effectively improve the photocatalytic activity of photocatalytic materials. In this paper, a p-p Z-scheme hererojunction composed of bismuth oxybromide and oxygen-rich bismuth oxybromide was synthesized via facile one-step solvothermal method. Based on the characterization results, we demonstrated that the BiOBr/Bi12O17Br2 Z-scheme heterojunction was synthesized by intimate interface contact between BiOBr and Bi12O17Br2 p-type semiconductors. This endowed the heterojunction composite with excellent photogenerated carrier transfer ability and photogenerated electron-hole separation performance compared with pure BiOBr and Bi12O17Br2 materials, which were proven by photoelectrochemical measurement, photoluminescence spectra. The maximum photocurrent of BiOBr/Bi12O17Br2 (≈0.32 μA) is approximately 3 times that of the original BiOBr (≈0.08 μA ) when light is irradiated. In addition, the BiOBr/Bi12O17Br2 p-p Z-scheme composite photocatalyst had good photocatalytic activity for sulfamethoxazole, with ·O2- free radicals as the main active species. It could photodegrade 99% sulfamethoxazole under light irradiation at 365 nm, and its degradation rate was approximately 13 times that of BiOBr and 1.5 times that of Bi12O17Br2 materials. Notably, BiOBr/Bi12O17Br2 exhibited an excellent performance after 4 consecutive runs. Besides, the possible degradation pathway of sulfamethoxazole was proposed. This work has reference significance for the construction of p-p Z-scheme heterojunctions and the treatment of environmental contaminants.