Influence of CoO_x surface passivation and Sn/Zr-co-doping on the photocatalytic activity of Fe₂O₃ nanorod photocatalysts for bacterial inactivation and photo-Fenton degradation

Hydrothermal and wet impregnation methods are presented in this study for synthesizing CoO_x(1 wt%)/Sn/Zr-codoped Fe₂O₃ nanorod photocatalysts for the degradation of organic pollutants and deactivation of bacteria. A hydrothermal route was used to synthesize self-assembled rod-like hierarchical structures of Sn(0–6%) doped Zr–Fe₂O₃ NRs. Additionally, a wet impregnation method was used to load CoO_x onto the surface of photocatalysts (Sn(0–6%)-doped Zr–Fe₂O₃ NRs). A series of 1 wt% CoO_x modified Sn(0–6%)-doped Zr–Fe₂O₃ NRs were synthesized, characterized, and utilized for the photocatalytic decomposition of organic contaminants, along with the killing of E. coli and S. aureus. In comparison with 0, 2, and 6% Sn co-doped Zr–Fe₂O₃ NRs, the CoO_x(1 wt%)/4%Sn/Zr–Fe₂O₃ NRs photocatalyst exhibited an E. coli and S. aureus inactivation efficiencies (90 and 98%). A bio-TEM study of treated and untreated bacterial cells revealed that the CoO_x(1 wt%)/4%Sn/Zr–Fe₂O₃ NRs photocatalyst led to considerable changes in the bacterial cell membranes’ morphology. The optimal CoO_x(1 wt%)/Sn(4%) co-doped Zr–Fe₂O₃ NRs photocatalyst achieved degradation efficiencies of 98.5% and 94.6% for BPA and orange II dye, respectively. As a result, this work will provide a facile and effective method for developing visible light-active photocatalysts for bacterial inactivation and organic pollutants degradation.