Boosted charge separation and reactive species generation in CuO-modified Hf/Be co-doped Fe₂O₃ photocatalysts for organic pollutant and bacterial removal

The advancement of effective photocatalysts for wastewater remediation and microbial inactivation is crucial for tackling global water pollution. In this work, we report the design and fabrication of a CuO-loaded Hf/Be co-doped Fe₂O₃ (Hf/Be-HT) photocatalyst with improved photocatalytic efficacy under solar irradiation. The photocatalytic activity was assessed utilizing Orange II dye, bisphenol A (BPA) and E. coli as representative contaminants. The Hf/Be-HT photocatalyst attained 93.9% degradation of Orange II within 90 min, adhering to pseudo-second-order kinetics (R² = 0.99444) and unveiling an apparent rate constant (k_app) of 0.025 min⁻¹. Moreover, the degradation efficiency of BPA reached 81.6% after 5 h, markedly surpassing that of the Hf-doped counterpart (55.4%). Additionally, Hf/Be-HT exhibited remarkable antibacterial activity, achieving 99.8% inactivation of E. coli within 120 min of exposure to light. Radical scavenger experiments revealed that photogenerated holes (h⁺) were the predominant reactive species, supplemented by ^•OH and ^•O₂⁻. The synergistic effect of Hf and Be co-doping, along with CuO modification, is shown to be an exceptionally effective strategy for enhancing hematite-based photocatalysts. These findings offer new insights into the design of multifunctional photocatalysts aimed at sustainable water purification.