Enhanced photodegradation performance of Zn-BiPO₄ on RhB and TC under the synergistic effect of oxygen vacancies and built-in electric field

In this work, Zn²⁺ ions doped BiPO₄ photocatalyst was successfully prepared by one-step hydrothermal method for the first time. The degradation rates of the optimal sample on RhB and TC solution reached 91.5 % and 81.25 % under simulated sunlight exposure for 3 and 5 hours, respectively, while pure BiPO₄ only reached 59.22 % and 49.4 %. The improved photocatalytic performance was due to the synergistic effect of oxygen vacancies and built-in electric field. The EPR test demonstrated the generation of more oxygen vacancies in the optimal sample. Additionally, the electrochemical experiments showed that the photocurrent intensity of the optimal sample was about 3 times than that of pure BiPO₄, indicating an enhanced carrier separation and transfer ability after doping Zn²⁺ ions. Through density functional theory (DFT), the incorporated Zn²⁺ ions caused the contraction of crystal structure and the redistribution of charges, leading to a built-in electric field. As few studies pay attention to the relationship between oxygen vacancies and the built-in electric field. This study has enlightening significance for the construction of photocatalysts with oxygen vacancies and built-in electric field through doping engineering.