Impact of Interfacial Electron Transfer on Electrochemical CO₂ Reduction on Graphitic Carbon Nitride/Doped Graphene

Effective electrocatalysts are required for the CO₂ reduction reaction (CRR), while the factors that can impact their catalytic activity are yet to be discovered. In this article, graphitic carbon nitride (g-C₃ N₄ ) is used to investigate the feasibility of regulating its CRR catalytic performance by interfacial electron transfer. A series of g-C₃ N₄ /graphene with and without heteroatom doping (C₃ N₄ /XG, XG = BG, NG, OG, PG, G) is comprehensively evaluated for CRR through computational methods. Variable adsorption energetics and electronic structures are observed among different doping cases, demonstrating that a higher catalytic activity originates from more interfacial electron transfer. An activity trend is obtained to show the best catalytic performance of CRR to methane on C₃ N₄ /XG with an overpotential of 0.45 V (i.e., -0.28 V vs reverse hydrogen electrode [RHE]). Such a low overpotential has never been achieved on any previously reported metallic CRR electrocatalysts, therefore indicating the availability of C₃ N₄ /XG for CO₂ reduction and the applicability of electron transfer modulation to improve CRR catalytic performance.