High Carrier Separation Efficiency in Morphology-Controlled BiOBr/C Schottky Junctions for Photocatalytic Overall Water Splitting

As a graphene-like ternary layered material, BiOBr, has emerged as a promising material for photocatalytic degradation and water treatment; however, its potential application in photocatalytic H 2 generation has not been explored clearly. In our study, BiOBr/C Schottky junctions with two stack forms, the parallel and vertical junctions, were prepared controllably via CVD. Their applications in photocatalytic H 2 generation and overall water splitting have been investigated systematically. Both the parallel and vertical junctions show a breakthrough in light response and H 2 generation under visible light (λ > 420 nm). The high H 2 generation rate of the parallel junctions can reach up to 2850 μmol h –1 g –1, which is 18 times more than that of the vertical ones, because of the greatly enhanced efficiency of carrier separation. In particular, the parallel junctions exhibit excellent photocatalytic overall water splitting, with an H 2 generation rate of 240 μmol h –1 g –1 and oxygen generation rate of 110 μmol h –1 g –1 . The active site of the H 2 reduction reaction of the two junctions is determined, and the transfer of photogenerated carriers is monitored by Kelvin probe force microscopy. On this basis, the mechanism of carrier separation of parallel and vertical junctions has been analyzed. This work pushes the series of ternary layered materials of BiOBr toward the applications of photocatalytic H 2 generation and overall water splitting.