In situ electrochemical reduced Au loaded black TiO2 nanotubes for visible light photocatalysis

Black TiO2 is identified as a promising photocatalyst because it makes up for the low visible light absorption performance, insufficient solar-light utilization, and slow carrier separation of TiO2. Nevertheless, the shortage of efficient and facile modification methods restricts the improvement of photocatalytic degradation ability. Hence, we proposed a convenient method to prepare Au-loaded black TiO2 nanotubes. During in situ electrochemical reductions, TiO2 nanotubes were transformed into black TiO2 nanotubes, meanwhile, Au was facilely modified on black TiO2 nanotubes. After loading Au, the electron density outstandingly increased to 6 times that of Au-unloaded TiO2 nanotubes because Au efficiently transferred electrons and promoted carrier separation. Consequently, the Au-loaded black TiO2 nanotubes had preferable visible-light photocatalytic performance. 82% RhB was degraded in 60 min and the AQY was 0.85%, which was approximately 2 times and 4 times larger than Au-unloaded TiO2 nanotubes, respectively. Such an in-situ Au modification design provided convenient routes for synthesizing Au-loaded black TiO2 nanotubes with enhanced visible light catalytic performance and further expanding their application potential in the field of photocatalysis.