Unraveling the Mechanism on Ultrahigh Efficiency Photocatalytic H2O2 Generation for Dual-Heteroatom Incorporated Polymeric Carbon Nitride

Photocatalytic hydrogen peroxide (H2O2) production from dioxygen and water is regarded as a promising technology since it can achieve sustainable and green solar-to-chemical energy conversion. Herein, oxygen and potassium dual-heteroatom incorporated polymeric carbon nitride (O/K-CN) is rationally designed for H2O2 generation with an ultrahigh rate of 309.44 mu M h(-1) mg(-1), which surpasses that of other C3N4-based photocatalysts. The enhanced performance can be ascribed to the effective light absorption, fast charge transfer/separation, strong oxygen adsorption, and highly selective two-electron oxygen reduction reaction (ORR). Density functional theory calculations further confirm that the obtained O/K-CN is more favorable than others for electrons migrating from beta spin-orbital to pi* orbitals of O-2 molecule, thus optimizing O-2 molecule activation to promote the formation of intermediate species *OOH and decrease the energy barrier of H2O2 production. This work not only provides in-depth insights for the photocatalytic H2O2 generation mechanism, but also lays the foundation for further development of highly active photocatalysts for environmental remediation and energy conversion.

Automated summary

In this study, oxygen and potassium dual-heteroatom incorporated polymeric carbon nitride was designed to efficiently generate H2O2. The obtained material exhibited excellent properties in terms of light absorption, charge transfer/separation, oxygen adsorption, and oxygen reduction reaction, leading to high H2O2 production. This work provides valuable insights into the photocatalytic mechanism of H2O2 generation and lays the foundation for the development of highly active photocatalysts for environmental remediation and energy conversion.