Degradation mechanism of Ni, Zn co-doping on Ag₃PO₄ photocatalysts for enhancing photocatalytic performance under simulated sunlight

In this work, Zn-doped and Ni, Zn co-doped Ag₃PO₄ photocatalysts were successfully prepared. Photocatalytic degradation experiments demonstrated that the catalytic performance could be improved with increasing Zn²⁺ content. However, the doping concentration of Zn in Ag₃PO₄ is inherently limited. Herein, Ni ions were introduced into the lattice to improve the solid solubility of Zn²⁺ ions, thereby further narrowing the band gap, as a result, the carrier separation rate got significantly improved. Meanwhile, density of state calculations showed that the impurity states of Zn and Ni were all located inside the valence band when introduced into the Ag₃PO₄ lattice alone; but the simultaneous introduction of both of them generates an impurity level of Ni within the bandgap, which could act as a shallow trap to capture photogenerated electrons, thereby facilitating the migration and separation of the carriers. The co-doping of Ni and Zn effectively modulated the electron and band structure of Ag₃PO₄, thereby promoting the generation of more active species and enhancing the photocatalytic performance of Ag₃PO₄. This work provides a new reference for improving the pollutants degradation capability of photocatalysts by doping metal ions in the semiconductor.