On the Enhanced Reducibility and Charge Transport Properties of Phosphorous-Doped BiVO4 as Photocatalysts: A Computational Study

Phosphorous (P)-doped BiVO4 has been proposed as a promising photoanode for water splitting as it exhibits significant improvement of photocurrent density and photocatalytic O2 evolution rate. Previous findings suggest that substitution of V with P induces lattice polarization which facilitates electron-hole separations. However, little attentions have been paid to the mechanism underlying the observed changes in electronic conductivity due to oxygen vacancies. In this work, we carried out first-principles calculations to study the effect of P doping on the stabilities of oxygen vacancies and charge transport properties of the BiVO4 photocatalysts. Our computations reveal improved reducibility of the P-doped BiVO4 as reflect through the lower energies of oxygen vacancy formation. The generated oxygen vacancy yields two electron polarons localized at the two nearest V centers where one polaron is always trapped at the defect site. The calculated polaron hopping barriers and their mobilities obtained from k...