Improved H2O2 photogeneration on Rb-doped-polymeric carbon nitride via enhanced O2 adsorption

Abstract

The H₂O₂ yield is substantially hindered by the four-electron competitive reaction and limited oxygen-capture ability of PCN. We herein demonstrated a Rb⁺-modified PCN photocatalyst (CNR-0.5) for highly efficient H₂O₂ production, in which the introduction of Rb⁺ ions creates abundant edge active sites within the –CN/–OH groups of the triazine ring. The hydrophilicity and O₂ adsorption capacity of the PCN catalyst were significantly improved. As a result, CNR-0.5 achieved a relatively high H₂O₂ yield (2225.05 μmol g⁻¹ h⁻¹), which is 37.58 times higher than that of pristine PCN under white light-emitting diode (LED) light. Experimental and theoretical results demonstrated that CNR-0.5 followed a two-step single-electron O₂ reduction reaction pathway in the H₂O₂ photogeneration reaction. Additionally, the AQE of CNR-0.5 was 24.52% at 385 nm in an ethanol system with O₂ injection. The excellent photocatalytic H₂O₂ production performance of CNR-0.5 in a real water body broadens the path for practical applications of PCN materials in photocatalytic H₂O₂ production.