Design of porous ZrO2 with well-tuned band structures and strong visible-light harvesting via Zn doping for enhanced visible-light photocatalysis

As one of huge-gap semiconductors, zirconium dioxide (ZrO2) has been emerging as one of popular photocatalysts for treating wastewater, and the band gap engineering of ZrO2 for efficient visible-light harvesting and high-performance photocatalysis is probably the most important challenge. In this work, porous Zn doped Zr3+ZrO2 nanostructures with strong visible-light harvesting capacity were fabricated via a calcination process for tetracycline degradation. The obtained (Zn, Zr3+)-ZrO2 samples showed greatly narrowed band gaps and enhanced visible-light harvesting capacity. In addition, the photocatalytic performance of the (Zn, Zr3+)-ZrO2 nanostructures was studied with tetracycline degradation as a model reaction. Among these prepared samples, the optimal (Zn, Zr3+)-ZrO2-5% sample exhibited remarkably improved tetracycline degradation visible-light irradiation, and the apparent rate constant reached 0.04958 min-1, which was 7.05 times of pristine Zr3+ZrO2. The boosted photocatalytic performance of the (Zn, Zr3+)-ZrO2 nanostructures were mainly ascribed to Zn doping effects as along as the high surface areas. Finally, possible photocatalytic mechanism, degradation pathways, and toxicity assessment were also studied. Current results indicate the significant roles of Zn doping in regulation of band gaps and morphology control of ZrO2 for high-performance photocatalytic applications.