Novel BP/BiOBr S-scheme nano-heterojunction for enhanced visible-light photocatalytic tetracycline removal and oxygen evolution activity.

Designing heterojunction photocatalysts with strong interfacial interaction and matched band structure is an effective way to reduce the recombination of photogenerated carriers. Herein, the exfoliated black phosphorus (BP) nanosheets were coupled with BiOBr nanosheets having higher Fermi level, and thereby it constructed a novel layered BP/BiOBr nano-heterojunction with chemically bonding, larger contact interface and unique band structures. BiOBr nanosheets were self-assembled on the surface of BP nanosheets by a facile liquid-phase ultrasound combined with solvothermal method. The photocatalytic performance for tetracycline (TC) degradation, oxygen evolution and H2O2 production rate of Sol-10BP/BiOBr was 7.8, 7.0 and 2.6 times than that of pure BiOBr, respectively. The in-situ generated H2O2 and OH became the main active species of mineralization and decomposition of TC. The novel S-scheme two-dimensional BP/BiOBr nano-heterojunction for boosting spatial charge separation retained the useful holes-electrons with higher redox ability, which was very beneficial for producing more OH, H2O2 and O2, and the photocatalytic activity was greatly improved.