Regulating Local Electron Density of Cyano Sites in Graphitic Nitride Carbon by Giant Internal Electric Field for Efficient CO₂ Photoreduction to Hydrocarbons

Abstract

Selective photocatalytic CO2 reduction to high‐value hydrocarbons using graphitic carbon nitride (g–C3N4) polymer holds great practical significance. Herein, the cyano‐functionalized g–C3N4 (CN–g–C3N4) with a high local electron density site is successfully constructed for selective CO2 photoreduction to CH4 and C2H4. Wherein the potent electron‐withdrawing cyano group induces a giant internal electric field in CN–g–C3N4, significantly boosting the directional migration of photogenerated electrons and concentrating them nearby. Thereby, a high local electron density site around its cyano group is created. Moreover, this structure can also effectively promote the adsorption and activation of CO2 while firmly anchoring *CO intermediates, facilitating their subsequent hydrogenation and coupling reactions. Consequently, using H2O as a reducing agent, CN–g–C3N4 achieves efficient and selective photocatalytic CO2 reduction to CH4 and C2H4 activity, with maximum rates of 6.64 and 1.35 µmol g‐1 h‐1, respectively, 69.3 and 53.8 times higher than bulk g–C3N4 and g–C3N4 nanosheets. In short, this work illustrates the importance of constructing a reduction site with high local electron density for efficient and selective CO2 photoreduction to hydrocarbons.