TiO nanorod/nanotube interface reconstruction and synergistic role of oxygen vacancies and gold in H-Au-TiO NR/NT for photoelectrochemical bacterial inactivation and water splitting.

Photoelectrochemical (PEC) water splitting by semiconductor photoanodes is limited by sluggish water oxidation kinetics coupled with serious charge recombinations. In this paper, an effective strategy of TiO nanorod/nanotube nanostructured interface reconstruction, oxygen vacancies and surface modification were employed for stability and efficient charge transport in the photoanodes. Successive anodization and hydrothermal routes were adopted for the TiO NR/NT photoanodes interface reconstruction, followed by Au nanoparticles/clusters (Au NP) loading and hydrogen treatment. This resulted in H-Au-TiO NR/NT photoanodes. A three-dimensional structure of TiO NR on TiO NT/Ti foil nanotubes achieved the highest photocurrent density (1.42 mA cm at 0.3 V vs. Ag/AgCl). The optimal oxygen vacancies and Au NP loading on TiO NR/NT exhibited 1.62 mA cm photocurrent density at 0.3 V vs. Ag/AgCl in H-Au-TiO NR/NT photoelectrode, which is eight times higher than the TiO NT/Ti foil. TRPL analyses confirm the hydrogen treatments to TiO exhibited the emission lifetime (46 ns) in the H-Au-TiO NR/NT photoanodes due to newly formed lower Ti-related trapped electron states and Au NP. The optimum H-Au (4)-TiO NR/NT photoanodes achieved 95% photoelectrochemical (PEC) bacterial inactivation and effective PEC water splitting with (278 and 135.4) μmol of hydrogen and oxygen generation, respectively. In this study, oxygen vacancies combined with gold particles and interface reconstruction provide an innovative way to design effective photoelectrodes.