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

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 O-2 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 O-2. The Z-scheme contribution is that the electrons in conduction band of Co9S8 are responsible for the major two-electron reduction of O-2, while the holes in valence band of Mn3O4 achieve the (OH)-O-center dot generation as another channel for H2O2 production. The photogenerated H2O2 can be efficiently used as an in situ oxidant to accomplish dyes degradation.