Modulation Of Photocatalytic Performance Of BiVO₄ By Doping Ce Ions

In the field of new clean energy development and organic pollution treatment,safe and environmentally friendly semiconductor photocatalysis technology has become a hotspot of current scientific research.Bismuth vanadate（Bi VO4）with visible light response is a new kind of semiconductor photocatalyst,which can improve the utilization of sunlight and the photoelectron chemical transmission performance,and has a great application prospect in the photocatalytic hydrogen production and photocatalytic degradation of organic matter.In this article,we report density functional theory（DFT）investigation on the formation of the native defects and Cerium doping in monoclinic Bi VO₄（m-Bi VO₄）and their effect on the electronic structures,using the Perdew-Burke-Ernzerhof functionals corrected for on-site Coulombic interactions（PBE+U）.From the point defect formation energies and transition levels,the Bi_vac（Bi vacancy）,V_vac（V vacancy）,O_int（O interstitial）and Ce V（Ce doping on V site）defects in m-Bi VO₄ are identified as shallow acceptors.For Ce doping in m-Bi VO₄,substitution of Bi by Ce is energetically favorable in the single positively charged state(Ce_Bi¹⁺)under Bi/V-poor conditions,while substitution of V by Ce is in the single negatively charged state(Ce_V^1-)under O-rich conditions.The calculated electronic structures suggest that Ce_Bi¹⁺degrades the activity by an unoccupied deep level in the gap region,mainly composed of Ce 4f orbitals,which makes this defect as the photogenerated electron-hole recombination center,in good agreement with experimental results.For Ce_V^1-,no localized state exists within the calculated band gap.Its formation energy is all sensitive to the chemical potentials and Fermi energy,suggesting that the Bi/V-poor and O-rich conditions are desirable to eliminate the deep-level states and to improve photocatalysis.Our results provide insights into how to enhance the photocatalytic activity of m-Bi VO₄ for energy and environmental applications through rational design of defect controlled synthesis conditions.