In-situ construction of Z-scheme 2D/2D g-C3N4/BiOBr heterojunction with enhanced photocatalytic CO2 reduction

Abstract

A novel series of g-C3N4/BiOBr (CN/BOB) Z-scheme heterojunction catalysts with two-dimensional/two-dimensional (2D/2D) morphology were synthesized by an in-situ hydrolysis method for photocatalytic CO2 reduction. Without adding any sacrificial agents or co-catalysts, the optimal CN/BOB heterostructure exhibits a boosted CO generation rate of 20.1 μmol·g-1·h-1 under the simulated solar light irradiation, severally being 1.7 and 3.7 times that of pristine BiOBr and g-C3N4. The enhanced performance principally benefit from the 2D/2D microstructure and Z-scheme heterojunction of photocatalysts. The intimate contact of 2D/2D morphology signifies more transmission channels and shorter transfer interface distance of photogenerated charges. While relevant characterizations and first-principles calculations jointly demonstrate that the Z-scheme heterojunction could significantly accelerate the spatial separation and transfer of photo-induced carriers, and evidently promote the redox ability of photocatalysts. The research furnishes a novel strategy to construct a promising bismuth oxyhalide based heterojunction catalyst for the application of photocatalytic CO2 reduction.