Z-scheme Bi2O2.33/Bi2S3 heterojunction nanostructures for photocatalytic overall water splitting

Abstract Photocatalysts with a wide response to solar spectrum especially to visible light are supposed to have a high energy conversion efficiency in solar water splitting. Heterogeneous binary composite photocatalysts exhibit outstanding performance in solar light absorption and photocarrier transfer/transport. In this work, a Z-scheme photocatalyst based on Bi2O2.33/Bi2S3 heterojunction is successfully designed and fabricated by assembling Bi2S3 nanoneedles on Bi2O2.33 nanosheets. Benefiting from the effective light absorption of Bi2S3 to solar light and the facilitated charge transfer by the Z-scheme band structure of Bi2O2.33/Bi2S3, the composite photocatalyst exhibits a fascinating photocatalytic performance in water splitting. With the help of Pt as a co-catalyst and sacrificial agent, the production rate of H2 can reach 62.61 μmol·h-1(sample area 2 cm2). The direct Z-scheme junction also exhibits the capacity of overall water splitting. Moreover, the stability of the heterojunction photocatalyst is optimized by depositing an ultra-thin amorphous TiO2 layer (about 3 nm) to avoid photocorrosion of Bi2S3. This work will provide a new insight into the design and development of efficient and long-life photocatalysts.