Near-infrared light photocatalysis and photothermy of carbon quantum dots and au nanoparticles loaded titania nanotube array

Highlights: • A novel ternary Au nanoparticles and carbon quantum dots loaded TiO₂ nanotube array system. • Near-infrared light photocatalysis due to the upconversion of carbon quantum dots and catalysis of Au nanoparticles. • TiO₂ nanotubes/Au/ carbon quantum dots can kill bacteria with 96.19 % (Staphylococcus aureus) and 99.89 % (Escherichia coli) antibacterial efficiency within 15 min. -- Abstract: The excellent photocatalysis is quite important for coating materials on implants, which can be photoinspired to kill bacteria by locally producing the reactive oxygen species (ROS) within a very short time. Herein, we developed a novel photocatalytic system of Au nanoparticles and carbon quantum dots loaded TiO₂ nanotube array (TNTs/Au/CDs) on the surface of titanium. This system can exhibit enhanced near-infrared (NIR) light photocatalysis and photothermy because CDs can convert NIR light into the light of 500–600 nm and transfer electrons, which can inspire nano Au-catalyzed TNTs to generate ROS and enhance the surface plasmon resonance (SPR) effect of Au nanoparticles to produce more local photothermy. The enhanced photocatalysis and local photothermy can exhibit a synergistic effect to kill the bacteria highly effectively within a very short time by damaging the membranes of the bacteria. The antibacterial efficiency of the modified surface is 96.19% and 99.89% against Staphylococcus aureus and Escherichia coli, respectively, under 808 nm NIR light irradiation for 15 min.