Constructing a nickel complex/crystalline carbon nitride hybrid with a built-in electric field for boosting CO2 photoreduction†

Abstract

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.