Construction of BiO2-x/Bi2O2.75 heterojunction for highly efficient photocatalytic CO2 reduction

Nowadays, using solar energy to convert CO2 into hydrocarbon fuels such as CO and methanol is considered as an attractive approach to alleviate environmental pollution and the energy crisis. However, the easy recombination of photo-generated carriers and holes of photocatalyst is still the main factor that inhibits photocatalytic performance for CO2 conversion. In this study, the BiO2-x/Bi(2)O2.75 heterojunction complex was successfully synthesized via a facile hydrothermal method. The BiO2-x/Bi(2)O2.75 heterogeneous catalyst shows greatly improved photocatalytic performance for CO2 reduction, and the CO and CH4 yields obtained on BiO2-x/Bi(2)O2.75 are 6.8 and 16 times compared with pure BiO2-x. The improved photocatalytic performance can be ascribed to the rapid charge separation on BiO2-x/Bi(2)O2.75 interface, thereby providing a favorable surface with suitable electronic structure for CO2 reduction. Subsequently, a possible photocatalytic mechanism was proposed to explain the improved performance of photocatalytic CO2 reduction.