Photoelectron “bridge” is introduced to realize the precise transport of C3N5-CoPc interface charge for efficient photocatalytic H2O2 production

Abstract

Noble metal-loaded semiconductor photocatalysts have attracted extensive attention in the field of photocatalytic two-electron oxygen reduction to generate H₂O₂ due to their high atomic utilization rate. However, the rareness and high cost of materials significantly hinder their industrial application. Here, we introduce phosphate as an electron bridge in carbon nitride (C₃N₅)-cobalt phthalocyanine (CoPc) (C₃N₅-YP-XCoPc) to enable the accurate transmission of photogenerated electrons to the metal Co atoms, and then excite them as catalytic centers to achieve the efficiency of a noble metal-like loaded semiconductor photocatalyst. The photocatalytic H₂O₂ yield of C₃N₅-8P-0.9CoPc is as high as 3080.3 μmol g⁻¹ h⁻¹, which is 8.3 and 4.4 times higher than C₃N₅ and C₃N₅-0.9CoPc, respectively. Experimental and theoretical calculations demonstrate that photogenerated electrons are precisely transported to Co atoms via phosphate molecules, exciting the Co 3d orbitals to higher energy levels, thereby making the Co atoms catalytic centers and enhancing their ability to adsorb and activate O₂. Meanwhile, phosphate passivated the adsorption of H₂O₂ on C₃N₅-8P-0.9CoPc and inhibited the in situ decomposition of H₂O₂. This work opens up new perspectives for the development of efficient photocatalysts, while demonstrating the potential of small molecules as bridging mediators.