Preparation of ZnO/two-layer self-doped black TiO2 nanotube arrays and their enhanced photochemical properties

Abstract

Highly efficient TiO₂ photoanodes can be achieved by enhancing electrical conductivity and improving charge separation and transfer. In this paper, Ti foils were used to fabricate TiO₂ nanotubes by anodic oxidation and ZnO/two-layer self-doped black TiO₂ nanotubes were prepared by electrochemical reduction and a hydrothermal method. The formed black TiO₂ nanotubes have a better photoconversion efficiency and the maximum photoconversion efficiency increased by 59% compared with the pure nanotubes. The deposition of ZnO further improves the maximum photoconversion efficiency to 456% based on black TiO₂. The photocurrent responses also increase by about 5 times in our results. This work is instructive for the development of highly robust and efficient photoanode materials in fields including photoelectrochemistry and photocatalysis.