Li Shuyi, Yan Xiaodan, He Jinlu
College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, P. R. China.
Phys Chem Chem Phys. 2023 Jul 19;25(28):18866-18873. doi: 10.1039/d3cp02066e.
Monoclinic bismuth vanadate (BiVO) has emerged as an excellent optically active photoanode material due to its unique physical and chemical properties. Experiments reported that the low concentration of oxygen vacancies enhances the photoelectrochemical (PEC) activity of BiVO, but the high concentration of oxygen vacancies decreases the charge carrier lifetime. Using time-domain density functional theory and molecular dynamics, we have demonstrated that the distribution of oxygen vacancies has strong effects on the static electronic structure and nonadiabatic (NA) coupling of the BiVO photoanode. The localized oxygen vacancies create charge recombination centers within the band gap and enhance the NA coupling between the VBM and the CBM, resulting in fast charge and energy losses. By contrast, the discrete oxygen vacancies can eliminate the charge recombination centers and decrease the NA coupling between the VBM and the CBM, enhancing the PEC activity of monoclinic BiVO. Our study suggests that the PEC performance of a photoanode can be improved by changing the distribution of oxygen vacancies.
单斜钒酸铋（BiVO）因其独特的物理和化学性质，已成为一种优异的光学活性光阳极材料。实验表明，低浓度的氧空位可增强BiVO的光电化学（PEC）活性，但高浓度的氧空位会降低电荷载流子寿命。利用时域密度泛函理论和分子动力学，我们证明了氧空位的分布对BiVO光阳极的静态电子结构和非绝热（NA）耦合有强烈影响。局域氧空位在带隙内形成电荷复合中心，并增强价带顶（VBM）和导带底（CBM）之间的NA耦合，导致快速的电荷和能量损失。相比之下，离散氧空位可消除电荷复合中心，并降低VBM和CBM之间的NA耦合，增强单斜BiVO的PEC活性。我们的研究表明，通过改变氧空位的分布可以提高光阳极的PEC性能。
