A step-by-step design for dual channel metal-free photocatalysts towards high yield H2O2 photo-production from air and water

Two-channel hydrogen peroxide (H2O2) released over metal-free catalysts is considered an efficient photocatalytic H2O2 production pathway. Step-by-step rational catalyst design remains a scientific bottleneck to obtain metal-free photocatalysts with practical prospects. Here, we demonstrate the step-by-step design of a dual-channel metal-free photocatalyst for high-yield H2O2 photoproduction. We constructed the heterojunction structure of CN-CRCDs while retaining the oxygen reduction capability of carbon nitride (CN) and the water oxidation capability of hexaketocyclohexane-derived carbon dots (CRCDs). The catalyst exhibits ultra-high photocatalytic performance, with high yield of 3023 μmol g-1h−1 for the photoproduction of H2O2 from air and water. Combined with photoelectrochemical experiments and transient photovoltage (TPV) analysis, the photocatalytic reaction sites and charge transport mechanism of the synthesized catalysts were elucidated. Continuous wavelet transform (CWT) and empirical mode decomposition (EMD) were applied to the in-depth analysis of charge behavior of heterostructures for the first time. This work provides clear insights into the stepwise rational design of metal-free heterostructure photocatalysts and their interfacial electron transport kinetics.