Highly efficient photocatalytic production of H2O2 by polyimide/In2S3 heterostructures under visible-light irradiation

The photocatalytic production of hydrogen peroxide (H2O2) through solar energy represents a sustainable, safe, and cost-effective approach. In this work, polyimide<bold>/</bold>In2S3 (PI/In2S3) type II heterojunction photocatalysts were fabricated successfully by using a hydrothermal method. The tight interface established between PI and In2S3 boosted the separation and transfer of photogenerated charge carriers. The photocatalytic H2O2 production rate of the PI/In2S3-2 sample with the PI to In2S3 mass ratio of 2:1 was as high as 378.48 mu mol g(-1) h(-1) under visible-light irradiation, which was 12.4 and 12.2 folds higher than pristine PI and In2S3, respectively. After five cycles of the experiment, the yield of H2O2 remained at 80% of that obtained in the first cycle. The active species trapping experiments indicated that electrons (e(-)) and superoxide radicals (<middle dot>O-2(-)) were the main species. These species participated in a two-step one-electron reduction process that converted O-2 into <middle dot>O-2(-) and subsequently led to the formation of H2O2. This work presents new insights into the construction of stable and efficient organic polymer/metal sulfide heterojunction photocatalysts.