Enhancing Photocatalytic Degradation via the Synergetic Effect of Vacancies and Built-In Potential in a BiOCl/BiVO4 p-n Heterojunction

Photoinduced charge separation and surface reactionsare essentialfor ensuring high quantum efficiency of the photochemical and photophysicalprocesses. BiVO4-based heterojunctions are promising materialsfor high-performance photocatalysts; however, their photocatalyticperformance is significantly lower than the theoretical limit dueto the sluggish water oxidation dynamics and rapid recombination ofcharge carriers on the catalyst surface. To address these issues,oxygen vacancies (OVs) are introduced to a rationally designed BiVO4-based heterojunction using built-in potential and gradientOVs to promote the separation of carriers and increase the photocatalyticactivity. The heterojunctions with OVs exhibit a 2-fold increase inthe photocatalytic activity for phenol degradation compared with thatof pristine BiVO4. Additionally, density functional theoryis applied to elucidate the synergistic mechanism of light absorptionand charge separation in BiOCl/BiVO4 p-n heterojunctionphotocatalysts containing vacancies. The obtained results demonstratea synergistic effect of vacancies and the built-in potential, providinga pathway for defect engineering in photocatalytic processes.