Simple synthesis of BiOAc/BiOBr heterojunction composites for the efficient photocatalytic removal of organic pollutants

Given that the formation of p-n heterojunctions between semiconductors could effectively improve the activities of catalysts, a novel p-n BiOAc/BiOBr heterojunction composite was successfully synthesized. The introduction of BiOAc improved the morphology of the BiOBr and formed flower-like nanostructured BiOAc/BiOBr composites. Rhodamine B (RhB) was degraded by similar to 98% under 5 W LED light irradiation (lambda > 390 nm) within 15 min on 10 wt% BiOAc/BiOBr samples, which was much higher than that on pure BiOBr (similar to 70%). Under the same conditions, 75% and 50% of Ciprofloxacin (CIP) was degraded within 120 min on 10 wt% BiOAc/BiOBr and BiOBr, respectively. This enhanced photocatalytic activity was attributed to the existence of a heterojunction electric field that was formed at the BiOAc/BiOBr interface. The dominant active species in the photocatalytic system were identified as h(+) and center dot O-2(-) via radical trapping experiments and ESR analysis. Finally, a potential photocatalytic mechanism over the BiOAc/BiOBr composites was proposed.

Automated summary

A novel p-n BiOAc/BiOBr heterojunction composite was successfully synthesized, showing significantly enhanced photocatalytic activity due to the heterojunction electric field formed at the interface. The main active species identified were h(+) and center dot O-2(-), which effectively degraded Rhodamine B and Ciprofloxacin under LED light irradiation. The study proposed a potential photocatalytic mechanism for the BiOAc/BiOBr composites.