Recent advances in graphitic carbon nitride supported single-atom catalysts for H2O2 production

Abstract

Graphitic carbon nitride (g-C₃N₄) has emerged as a promising support for single-atom site catalysts (SACs) in the photocatalytic synthesis of hydrogen peroxide (H₂O₂) due to its visible-light-responsive properties and periodic nitrogen coordination sites to offer distinct advantages for stabilizing metal single atoms. In this paper, the latest progress in the photocatalytic synthesis of H₂O₂ using g-C3N4-supported SACs is systematically summarized. Firstly, based on the introduction of g-C3N4-supported SACs, the catalytic mechanism of single-atom active site selectivity was clarified, and the two-electron oxygen reduction reaction path was revealed-by regulating the adsorption configuration of oxygen molecules and optimizing the formation path of key intermediate OOH*. Furthermore, different single-atom synthesis methods, such as calcination and deposition, are summarized, and the selection and optimization of reaction conditions are analyzed for the commonly used calcination process. Meanwhile, the application of advanced characterization techniques such as high-resolution transmission electron microscope (HRTEM) and X-ray absorption spectroscopy (XAS) in the detection of single-atom dispersion and local coordination environment is comprehensively reviewed. In addition, from the two dimensions of single-atom type selection and carrier regulation, the design optimization strategy of SACs based on g-C3N4 in H2O2 photocatalytic synthesis was discussed. Finally, based on the latest research progress, the key challenges were analyzed from four aspects: g-C3N4, SACs, reaction mechanism and industrialization, and the future perspectives was given, which provided a reference for the follow-up research.