A dipole-polarized Ni–Bi atomic interface synergistically promotes the photocatalytic nitrogen reduction reaction

Abstract

The photocatalytic nitrogen reduction reaction (pNRR) is an environmentally friendly synthetic way that uses solar energy to convert H₂O and N₂ directly into NH₃. However, the absence of efficient active sites constitutes a limiting factor in the pNRR. In this study, we synthesized a Ni-doped BiOBr nanoflower photocatalyst that exhibits a dipole polarization effect, achieving an efficient pNRR with a high yield of ammonia (436.38 μmol g_cat⁻¹ h⁻¹) and an apparent quantum yield (AQY) of 2.84% at 365 nm. Mechanistic studies have demonstrated that the modulation of the photocatalyst's band structure enhances the reduction capability, and the localized polarization along the Ni–Bi interface facilitates a photoinduced charge transfer process, further improving the adsorption/activation of N₂ and promoting the nitrogen to ammonia conversion pathway. Density functional theory (DFT) calculations suggest that the Ni-doping of BiOBr reduces the energy barrier of the pNRR, with the rate-determining step decreasing from 2.13 to 1.87 eV. This work supports a pathway for optimizing the photoreduction of N₂ via dipole polarization effects and band structure modulation.