Hot-Electrons Mediated Efficient Visible-Light Photocatalysis of Hierarchical Black Au–TiO₂ Nanorod Arrays on Flexible Substrate

Rational engineering hierarchical 3D nanostructures with high visible-light photocatalysis and long-term cycling stability are of great importance in environmental purification and energy conversion. A novel and scalable approach is demonstrated to fabricate hierarchical plasmon-resonance-induced black Au–TiO₂ nanorod arrays (NRAs) on flexible carbon cloth (CC). With the advantages of hierarchical morphology, plasmon-enhanced visible-light absorption, facile charge separation enabled by single-crystalline TiO₂ and conductive substrate, the black Au–TiO₂ NRAs on CC show more than 13 times higher visible-light photocatalytic efficiency enhancement compared to that of bare TiO₂ NRAs. Meanwhile, the hybrid Au–TiO₂–C system shows extremely high chemical and mechanical stability. The visible-light photocatalysis does not show any decrease after consecutive seven times test. More remarkably, after being continuously stirred in aqueous solution for 60 d, almost no decrease of photocatalytic activity is observed. The UV–vis absorption measurement, optical simulations, and the control experiment on hierarchical Au–SiO₂@TiO₂ NRAs reveal that the enhanced visible-light photocatalysis is caused by the plasmon-induced hot-electrons transfer from Au nanoparticles to neighboring TiO₂ NRAs. The high visible-light photocatalytic performance and the excellent chemical/mechanical stabilities imply that the black Au–TiO₂ NRAs on CC can serve as potential photocatalytic materials for large-scale applications in energy conversion and pollutants purification.