A Polyimide-Based Photocatalyst for Continuous Hydrogen Peroxide Production Using Air and Water under Solar Light

Hydrogen peroxide (H2O2) is a clean disinfectant, bleaching agent, and value-added fuel in various systems and is industrially produced through multistep energy-intensive hydrogenation/oxidation using H-2 and O-2. The exploitation of metal-free catalysts for alternative H2O2 photoconversion is limited by their limited activity and selectivity, especially for the continuous H2O2 production using only air, water, and solar light. Now, a cheap and robust polymer, poly (4,4 ',4 ''-(1,3,5-triazine-2,4,6-triyl)triphenyl pyromellitimide) (PTTPI) was rationally synthesized by thermal structure-defect control under relatively low temperature (80-190 degrees C), and the resulting metal-free material with a concisely refined band structure functioned as an efficient and ultra-stable photocatalyst for H2O2 production over a wide pH range. The PTTPI photocatalyst with an optimized defective degree (0.51) and moderate bandgap (2.3 eV) exhibited a H2O2 production yield rate of 16.6 mu g h(-1) mg(cat)(-1) and a high apparent quantum efficiency of 16.2%. By merging the well-designed PTTPI catalyst with the water transport path of natural cotton, a zero-emission and sunlight-only input system is constructed for continuous H2O2 production from air and water in the natural environment. The design of the polyimide-based catalyst reveals a sustainable future toward efficient H2O2 synthesis with sunlight-only energy input, enabling its implementation in other photocatalytic systems and on-site processing communities.