Boosted charge transfer from single crystalline titanium nanotubes for a dual-purpose PEC system

Photoelectrocatalytic (PEC) technology has promising applications. It is capable of effectively generating hydrogen and removing organic pollutant in water at the same time. Though TiO 2 materials have been proven an excellent candidate for fabricating PEC electrodes for its low toxicity, high oxidation potential and photocatalytic activity, the catalytic performance of TiO 2 electrodes is limited by their low electrons transporting efficiency. In this study, using a facile electrochemical method , we produced single crystalline TiO 2 nanotubes (s-TNTs) exposing {001} facets with enhanced charge transfer efficiency than that of common TiO 2 nanotubes electrodes (m-TNTs). In this system, the electrochromic s-TNTs electrodes exhibit better performance in generating hydrogen and higher degradation rate of atrazine on s-TNTs than that on common TiO 2 nanotubes electrodes (m-TNTs) in varying conditions: electrochemical (EC), photocatalytic (PC), and PEC. Using s-TNTs and s-TNTs@Pd nanocomposites as both photoanode and cathode, the photon-to-current conversion efficiency was significantly enhanced, and the promoted hydrogen production rose obviously. The enhanced charge transfer efficiency of s-TNTs might induce a highly enhancement in the whole PEC system, which could be primarily attributed to the single-crystalline structure and exposed {001} facet. This study could provide new possibility of utilizing single crystalline TiO 2 nanotubes for efficient dual-purpose PEC system for its high activity, great stability, low cost and no toxicity.