Ultra-low Au–Pt Co-decorated TiO₂ nanotube arrays: Construction and its improved visible-light-induced photocatalytic properties

Highly ordered TiO₂ nanotube arrays (TNTAs) have been controllably prepared by anodizing Ti foils and been used as the support for co-depositing noble Au–Pt quantum dots (QDs) with good dispersion. Well dispersed Au–Pt nanoparticles around 5 nm have been simultaneously deposited on the TNTAs through a facilely simultaneous photo-irradiation-reduction method. The prepared samples have been well-characterized by SEM, TEM, XRD, XPS, UV–Vis and EC-AFM methods. The photo-degradation of Rh B under visible light (with a 420 nm cutoff) has been used as a model response to characterize the photocatalytic properties of the prepared samples; and the co-decorated Au–Pt/TNTAs show a remarkable enhancement of visible-light-driven photocatalytic properties with good stability. This shows that the co-decorated Au–Pt quantum dots could effectively utilize the visible light and suppress the recombination of electron-hole pair, although the loaded amount is ultra-low, which induces an optimized photocatalytic activity under visible light.