Constructing a nickel complex/crystalline carbon nitride hybrid with a built-in electric field for boosting CO ₂ photoreduction

Sluggish charge separation dynamics resulting from the amorphous structure and the lack of driving force for graphitic carbon nitride (GCN) limits its highly effective CO₂ photoreduction performance. Herein, a built-in electric field (BEF) was constructed for a well-designed CCN/Ni hybrid composed of crystalline carbon nitride (CCN) and a metal complex, 2,2'-bipyridine-4,4'-dicarboxylic acid NiBr₂ (dcabpyNiBr₂), to steer charge carrier separation and migration. The CCN/Ni hybrid was synthesized via a solution-dispersion and molten-salt two-step approach, displaying an improved CO₂ photoreduction to CO rate of 8.64 μmol g^-1 h^-1. In situ experimental results and theoretical simulations further investigated the relationships between BEF and photocatalytic activity. This work demonstrates an effective strategy to obtain high-efficiency photocatalytic systems by engineering the crystal structure and constructing a BEF.