Polyimide/ZnIn2S4 heterostructures toward outstanding photocatalytic H2O2 production from pure water and air

The photocatalytic production of H2O2 using the abundant water and air on earth is promising. Herein, the flower-like polyimide/ZnIn2S4 heterostructures were prepared by a simple two-step solvothermal method, where the tight interface formed between polyimide (PI) and ZnIn2S4 microspheres facilitated the separation and migration of photo-generated charges. Under air condition, the photocatalytic H2O2 production rate without any sacrificial agent is as high as 411.07 μmol g-1h−1, which is 15.4 and 3.2 times higher than that of the pristine PI and ZnIn2S4 microspheres, respectively. Meanwhile, the PI/ZnIn2S4-2 has excellent reusability, and the H2O2 production of PI/ZnIn2S4-2 maintained 80 % of its original value after five cycles. Moreover, the as-prepared samples underwent comprehensive characterization using various techniques, and the photocatalytic mechanism was also studied in depth. Active species capture experiments showed that e− and ·O2− played a primary role in this reaction system. This work provides a novel idea for photocatalytic H2O2 production in pure water and air.