Simultaneous copper ion removal and hydrogen production from water over a TiO2 nanotube photocatalyst

A one-dimensional (1-D) mesoporous TiO2 nanotube (TiNT) was successfully synthesized via a hydrothermal-calcination process, and employed in simultaneous photocatalytic Cu2+ removal and H-2 production. Under irradiation, Cu2+ in the wide concentration range of 8-800 ppm, could be reduced rapidly, and the reduction was not severely impacted by co-existing inorganic ions in solution. Simultaneous with Cu2+ reduction, noticeable H-2 was produced over the in-situ fabricated Cu incorporated TiNT (Cu-TiNT) photocatalyst, while H-2 evolution rate was controlled by the Cu2+ reduction process, due to competition of electron capture between protons and Cu2+. In addition, H-2 generation activity of Cu-TiNT depended on the initial Cu2+/ Ti ratio, and could be depressed by co-existing ions in solution. Fast Cu2+ reduction and remarkable H-2 evolution confirmed the feasibility of simultaneous Cu2+ removal and H-2 production over a TiNT photocatalyst.