Aluminum nanoparticle enhanced TiO2 photocatalysis of organic pollutants under solar and UV-B irradiation

Abstract Photocatalytic water treatment offers a sustainable method for removing organic micropollutants but is often limited by low efficiency and complexity. We report a plasmonic-photocatalytic heterostructure combining aluminum (Al) nanoparticles with titanium dioxide (TiO 2 ) for contaminant degradation under solar light without external oxidants or pH adjustment. Using an organic colloidal Al nanoparticle suspension, this approach enhances TiO 2 photocatalysis through improved light absorption, plasmon resonance, and contaminant adsorption. The low-cost Al/TiO 2 heterostructure provides light-harvesting benefits comparable to other noble metal heterostructures (Au/TiO 2 and Ag/TiO 2 ), offering a sustainable alternative. Synthesized via an organic solvent method and ligand modification, the heterostructures were characterized for charge, size, bandgap, and photocatalytic efficiency. A cysteine-modified Al/TiO 2 showed the best performance, degrading the dye amaranth 60% faster than P25 TiO 2 and remaining stable over repeated cycles, underscoring its potential for integration into small-scale, solar-driven water treatment systems.