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

Selective photocatalytic CO 2 reduction to high‐value hydrocarbons using graphitic carbon nitride (g–C 3 N 4 ) polymer holds great practical significance. Herein, the cyano‐functionalized g–C 3 N 4 (CN–g–C 3 N 4 ) with a high local electron density site is successfully constructed for selective CO 2 photoreduction to CH 4 and C 2 H 4 . Wherein the potent electron‐withdrawing cyano group induces a giant internal electric field in CN–g–C 3 N 4 , 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 CO 2 while firmly anchoring *CO intermediates, facilitating their subsequent hydrogenation and coupling reactions. Consequently, using H 2 O as a reducing agent, CN–g–C 3 N 4 achieves efficient and selective photocatalytic CO 2 reduction to CH 4 and C 2 H 4 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–C 3 N 4 and g–C 3 N 4 nanosheets. In short, this work illustrates the importance of constructing a reduction site with high local electron density for efficient and selective CO 2 photoreduction to hydrocarbons.