Critical roles of H2O and O2 in H2O2 photoproduction over biomass derived metal-free catalyst

In this paper, in-situ transient photoinduced-voltage combined with the continuous wavelet transform was used for the first time to study the critical roles of H2O and O2 in the H2O2 photoproduction. A metal-free photocatalyst containing carbon dots was synthesized by a one-step hydrothermal method using hesperidin as raw material. The photocatalytic H2O2 yield of the catalyst can reach 4480 μmol·L−1 under visible light without sacrificial agent. In addition to being raw materials, we have proved that H2O and O2 can regulate the photogenerated electron transport kinetics, namely, O2 can decelerate low-frequency electron transport, while H2O can accelerate the low-frequency electron transport. This work provides an in-depth understanding on photocatalytic production of H2O2 over composite metal-free photocatalysts and new insight for their design.