First-Principles Study of Electronic Structure and Optical Properties of Ni-Doped Bi[sub.4]O[sub.5]Br[sub.2]

In this study, we comprehensively explored the electronic structure and optical properties of Ni-doped Bi[sub.4]O[sub.5]Br[sub.2] through first-principles computational calculations. By calculating its electronic structure and band characteristics, we investigated the impact of Ni doping on the photocatalytic performance of Bi[sub.4]O[sub.5]Br[sub.2]. The computational results indicated that Ni doping significantly altered the band structure of Bi[sub.4]O[sub.5]Br[sub.2], leading to a reduction in the band gap width. The band gap for undoped Bi[sub.4]O[sub.5]Br[sub.2] was 2.151 eV, whereas the Ni-doped system exhibited a smaller band gap, directly indicating its enhanced visible light absorption capacity and facilitating the effective separation of photo-generated electron–hole pairs. Through analysis of 2D charge density maps, we observed changes in chemical bonding induced by Ni doping. The shortening of Ni-O bonds suggested increased bond strength, consistent with the observed reduction in cell volume. These findings provide a theoretical foundation for understanding the mechanisms behind the enhanced photocatalytic hydrogen production performance in Ni-doped Bi[sub.4]O[sub.5]Br[sub.2], offering valuable insights for the design and optimization of highly efficient photocatalytic materials.