MIL-68(In)-derived In2O3/In2S3/C: In situ synthesis and efficient visible-light photocatalytic H2O2 generation

Photocatalytic reduction of O-2 to generate H2O2 shows an excellent environment friendly nature and the controllable H2O2 concentrations and is found the prospect of applications in H2O2-assisted redox. In this paper, MIL-68(In) is chosen as a sacrifice precursor to construct a multi-component photocatalyst of In2O3/In2S3/C by integrated in situ sulfidation and pyrolysis routes. The resulting In2O3/In2S3/C inherited the geometry of MIL-68(In) and represents the hollow microtube with rough surface. The photocatalytic activity of the In2O3/In2S3/C in H2O2 generation is investigated systematically, and the contrast tests were conducted over the In2S3/MIL-68 synthesized by in situ sulfidation but without subsequent pyrolysis, to explore the advantages of the In2O3/In2S3/C heterostructure. The best photocatalytic H2O2 evolution is observed by the In2O3/In2S3/C with a value of 934.6 mu mol/L within 1 h, which is higher than that by In2S3/MIL-68 and other previously reported photocatalysts. The photoelectrochemical analyses and ESR measurements clarify that contact heterojunction and matched band potentials are responsible for the effective separation of electrons and holes, and the O-2(<middle dot>-) are the main active species in the photocatalytic H2O2 evolution. The outstanding photocatalytic activity, structure stability, and the easily regulated H2O2 concentrations render the In2O3/In2S3/C the prospect applications in the H2O2-assisted redox reactions.