In situ synthesis of a novel Mn3O4/g-C3N4 p-n heterostructure photocatalyst for water splitting

Designing high-efficiency photocatalyst for photocatalytic water splitting is a considerable challenge. Herein, a new Mn3O4/g-C3N4 p-n heterostructure photocatalyst is prepared by an in-situ growth method. The introduction of Mn3O4 can enhance light absorption ability of g-C3N4. The Mn3O4/g-C3N4 photocatalyst exhibits outstanding photocatalytic activity for hydrogen evolution reaction (HER) efficiency of ~2700 μmol g−1h−1 at λ > 420 nm. For the separate reactions of H2 evolution and O2 evolution under simulated sunlight, the efficiencies of Mn3O4/g-C3N4 heterostructure photocatalyst are 3300 μmol g−1h−1 and 654 μmol g−1h−1, respectively. The p-n junction is also capable of catalyzing the overall water splitting reaction to generate H2 and O2 products in a stoichiometric molar ratio of 2:1. The formation of electric field in p-n Mn3O4/g-C3N4 junction promotes electron transfer and improves photocatalytic performance.