Band structure-controlled P-C3N4 for photocatalytic water splitting via appropriately decreasing oxidation capacity

Abstract

In the reaction of photocatalytic water splitting, oxygen production has been the rate-limiting step, and the side-reactions caused by excessive oxidation capacity have become important factors affecting oxygen production. C3N4 was doped by phosphorus (P) to controllably reduce its oxidation performance while narrowing the band gap, so as to improve its light absorption ability and reduce the side-reactions caused by excessive oxidation capacity. Due to the much higher reducibility, C3N4 has been identified as an ideal carrier for this design philosophy, which can make up the power lack of producing O2 induced by the reduced oxidation capacity while P being doped. Successively, via adjusting the relationship between the overall water splitting activity and energy band structure of the catalyst, it was proved that the regulation of oxidation capacity has an important effect on the photocatalytic water splitting. The photocatalytic H2 and O2 evolution rates were 0.67 and 0.27 μmol h−1, respectively. This research will provide a new idea to improve the performance of overall water splitting with energy band structure regulation in the future.