Synchronous electrochemical anodization: A novel strategy for preparing cerium doped TiO2 nanotube arrays toward visible-light PEC water splitting

To enhance the photoelectrochemical (PEC) performance of TiO2 nanotube arrays (TNTAs), a facile but effective strategy is proposed to introduce Ce into TNTAs by simply adding cerium (Ce) ions to the fluorinated organic solution and then following with a traditional anodization treatment, in which the Ce ions can participate in the entire anodization process and grow synchronously with the formation of TiO2 nanotubes. It is found that the titanium nanotube arrays doped with a low concentration of Ce have the best performance, and the cerium element is uniformly doped in TNTAs. Excess cerium will aggregate on the surface to form cerium dioxide, causing the tube structure to be destroyed and resulting in a decrease in performance. Ce-doped TNTAs are greatly affected by the bias voltage. As applied bias voltage increases, Ce-doped TNTAs show enhanced PEC performance, and their absorption threshold is red-shifted to the visible light range significantly.