Dipole-polarized Ni-Bi atomic interface synergistically promotes photocatalytic nitrogen reduction reaction

Abstract

The photocatalytic nitrogen reduction reaction (pNRR) represents 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 efficient pNRR with a high yield of ammonia (436.38 μmol⋅gcat−1⋅h−1) and an apparent quantum yield (AQY) of 2.84% at 365 nm. Mechanistic studies have demonstrated that the modulation of photocatalysts' band structure enhances the reduction capabilities, and the localized polarization along the Ni-Bi interface facilitates the photoinduced charge transfer process, further improving the adsorption/activation of N2 and promoting the conversion of nitrogen to ammonia pathway. Density functional theory (DFT) suggests 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.