The morphology control and full-spectrum photodegradation tetracycline performance of microwave-hydrothermal synthesized BiVO₄:Yb³⁺,Er³⁺ photocatalyst

By adjusting the pH of the precursor solution, different morphologies of BiVO₄:Yb³⁺,Er³⁺-X (BYE-X) were successfully synthesized via a facile microwave hydrothermal method. Tetracycline was employed as a model pollutant to evaluate the full-spectrum photocatalytic activity of BYE-X samples. The experimental results revealed that when the pH ranged from 3 to 8, BYE showed pure monoclinic BiVO₄ phase. At pH values of 10−12, the synthesized samples had mixed phases of Bi₂O(OH)(VO₄), Bi₂O₃, and BiVO₄. A notable variation in the morphological characteristics of BYE was observed with the increasing pH values. The samples of different pH values showed obvious up-conversion luminescence. Due to the up-conversion of Er³⁺and Yb³⁺, the near-infrared (NIR) light was effectively utilized, successfully broadening the light response range. Under the visible or NIR light irradiation, BYE-5 demonstrated the optimal photodegradation activity. Based on the experimental results, a mechanism for full-spectrum photocatalysis was proposed. This work provides a feasible approach to improving the utilization of solar light by semiconductor catalysts, thereby achieving efficient full-spectrum photocatalytic activity.