Photocatalytic production of hydrogen peroxide over Z-scheme Mn3O4/Co9S8 with p-n heterostructure

Abstract

Photocatalytic production of H2O2 is a green and sustainable technique, which exposes the cost and environment issues with the dependence on organic electron donors and pure O2 before it is put into practice. Herein, we construct a p-n heterojunction of Z-scheme from the p-type Mn3O4 and n-type Co9S8 semiconductors for photocatalytic H2O2 production. Mn3O4/Co9S8 composites with the regulable morphology and structure exhibit improved photogenerated electrons transportability and e−-h+ pairs separation ability. An optimal photocatalyst obtains 1.6 mM of H2O2 for 6 h in alkaline medium without using electron donors and pure O2. The Z-scheme contribution is that the electrons in conduction band of Co9S8 are responsible for the major two-electron reduction of O2, while the holes in valence band of Mn3O4 achieve the OH generation as another channel for H2O2 production. The photogenerated H2O2 can be efficiently used as an in situ oxidant to accomplish dyes degradation.