Abstract
In the present research, we investigate the synergistic effects of Ru-doping and Ar/H-2 reduction treatment on the photoelectrochemical water splitting performance and hydrogen evolution rate of TiO2 nanotube array photoelectrodes. The Ti-Ru alloy with 0.2 at. % Ru was used to grow anodic self-organized Ru-doped TiO2 nanotube layers. An ideal synergy between Ar/H-2 reduction treatment and Ru-doping results in the extended absorption toward the visible light region and improved photoelectrocatalytic activity. The black Rudoped TiO2-x photoanode's water splitting rate improves remarkably (similar to nine-fold) compared to the black TiO2-x sample (similar to twofold). Moreover, the black Rudoped TiO2-x photoanode shows a considerable increase in the H-2 production rate (1.91 mu mol h(-1) cm(-2)) compared with the pristine TiO2 nanotube layer (0.044 mu mol h(-1) cm(-2)). We have also developed an ab initio model of pristine, Ru-doped, and Ru-doped hydrogenated TiO2 nanotubes to rationalize our experimental findings from the theoretical perspective.