Regulating active sites of Cu/Al₂O₃ by various -OH groups on Al₂O₃ and investigating its bactericidal performance...

Increasing dispersion of metal active components by regulating supports is a crucial way for developing high-efficient and low-cost antibacterial materials. Based on variation of the calcination temperature of pseudo-boehmite (AlOOH) precursor to regulate hydroxyl functional groups (-OH groups) of Al₂O₃, the roles of -OH groups in anchoring and dispersing Cu species on Cu/Al₂O₃ material were systematically investigated in this study. At the same time, the bactericidal activities and underlying mechanism of Cu/Al₂O₃ before and after phosphorization were thoroughly examined. Key findings revealed that the presence of terminal -OH groups and double-bridging -OH groups is crucial for effectively anchoring Cu atoms and enhancing their dispersion, resulting in robust bactericidal activity even at low Cu loading levels. Furthermore, phosphidation treatment significantly improved bactericidal activity by reducing Cu²⁺ to Cu⁺ and promoting the generation of superoxide radicals. Importantly, the synergistic oxidative damage of cellular membrane induced by extracellular reactive oxygen species (ROS) and intracellular ROS accumulation was found to be the primary mechanism of bacterial death. These findings provide insights into designing antimicrobial materials through hydroxyl‑mediated metal anchoring and phosphidation treatment.