Oxygenated P/N co-doped carbon for efficient 2e− oxygen reduction to H2O2

Abstract

Direct H₂O₂ production via the 2e⁻ electrocatalytic oxygen reduction reaction (ORR) offers unique prospects for sanitization and water purification. Search for cheap, effective, selective catalysts for this process is challenging. In this work, a type of doped carbon material with rich edged P atoms co-functionalized with O and N atoms was synthesized via simple solvothermal treatment of P₂O₅ in formamide, followed by inert annealing. The structures and compositions of O–P/N–C materials were systematically characterized and analyzed. The optimal O–P/N–C900 sample was revealed to contain high P content (2.49 at%) and N content (11.56 at%). Electrochemical measurements revealed that the O–P/N–C900 sample achieved a very high H₂O₂ yield rate of 698.4 mmol g_cat.⁻¹ h⁻¹ and a high Faradaic efficiency of 87% in a H-type cell. The density functional theory (DFT) calculations confirmed that the edged P atom with the co-functionalization of O and N atoms possessed the lowest energy barrier for promoting the selective 2e⁻ ORR, showing good alignment with experiments. This work provides a new strategy for the controllable synthesis of carbon materials decorated with oxygenated heteroatom doping for electrochemical H₂O₂ synthesis.