Dual photothermal-photocatalytic Au@ZIF-8/Ti₃C₂T_x nanocomposite for enhanced solar steam sterilization and biofouling-resistant hydrogel membrane

Solar-driven interfacial water evaporation holds great promise for water purification and desalination, but challenges such as insufficient light absorption, suboptimal energy conversion, and microbial contamination hinder its practical applications. This study presents a novel Au@ZIF-8/Ti₃C₂T_x alginate hydrogel, integrating nanocomposites into a three-dimensional hydrogel network to enhance both water transport and light-to-heat conversion. The incorporation of Au nanoparticles significantly improves light absorption, while the Schottky junction between ZIF-8 and Ti₃C₂T_x promotes photocatalytic generation of reactive oxygen species (ROS), including superoxide radicals (O₂⁻) and singlet oxygen (¹O₂). This photocatalytic activity, combined with the photothermal effects of Ti₃C₂T_x, leads to effective bacterial sterilization, achieving 99.54 % and 97.22 % antibacterial efficiency against E. coli and S. aureus, respectively. The hydrogel exhibits a high evaporation rate of 1.589 kg m⁻² h⁻¹ and demonstrates a 100 % steam sterilization rate against both bacterial strains under one sun illumination. These findings highlight the potential of the Au@ZIF-8/Ti₃C₂T_x alginate hydrogel as a promising, efficient, and cost-effective sterilization strategy for various applications, including water purification, desalination, and disinfection in off-grid areas and specialized settings.