Water-induced formation of Cs2AgBiBr6/BiOBr heterostructure with enhanced visible-light photocatalytic activity

The separation and transfer of photogenerated charges are limited by the deep energy defects and high exciton binding energy of Cs₂AgBiBr₆ (CABB). The creation of heterostructure is a great promising path to solve this obstacle. In this paper, BiOBr (BOB) nanosheets epitaxially grew on the surface of CABB octahedrons through immersing CABB into in water-solution with the assistance of ethanol, thereby creating an interesting CABB/BOB heterojunction. The CABB/BOB heterostructure markedly enhances water stability, preserving its structure and morphology even after being submerged in a mixture of ethanol and water for 100 h. The CABB/BOB photocatalyst exhibited significantly enhanced photocatalytic activity towards the degradation of Rhodamine B in comparison to its individual pristine components, namely CABB and BOB. Specifically, the advanced CABB/BOB−90 photocatalyst attains a degradation efficiency of 98 % within 40 min, significantly surpassing the initial CABB and BOB photocatalysts by approximately 1.3 and 4.1 times, respectively. The heightened photocatalytic activity is attributable to the formation of a tightly integrated heterojunction interface, which promotes the efficient separation of charge carriers.