Multiple heteroatom-doped urea and thiourea-derived polymeric carbon nitride for high-performance visible light-driven photocatalytic O2 reduction to H2O2

To photocatalytically reduce O2 to H2O2 over polymeric carbon nitride (PCN) in high efficiency is essential for practical application but remains a considerable challenge. Herein, we synthesized a K, S, and O co-doped PCN (akut-CN) via one-pot polymerization of urea and thiourea in the presence of KCl and NaOH, which afforded an unprecedentedly high H2O2 production rate of 4.46 mM h-1 under visible light irradiation, about 210 times that over the un-doped PCN. The heteroatom doping and the incorporation of the cyano and hydroxyl groups into akut-CN are identified to enhance light absorption, accelerate the separation and transfer of the photogenerated charges, and improve the surface electronegativity and the O2 adsorption capacity and strength, which collaboratively boosted the reaction kinetics. This work highlights the great potential of the elaborately decorated PCN in photocatalytic O2 reduction to H2O2 and paves the way to the decentralized production and application of H2O2.