Enhanced Photoelectrochemical Property of TiO₂ Nanotube Array Photoanode Deposited with Al,Cr-Codoped SrTiO₃ Nanocubes

There is a demand for the effective utilization of solar energy with highly functional photoelectrodes for photoelectrochemical (PEC) applications, such as water splitting and CO₂ reduction. TiO₂ nanotube arrays (TNTA) with a large surface area have been studied as potential photoelectrodes mainly due to their strong oxidation potential. However, it has disadvantages of fast charge recombination and little responsivity to visible light. In this study, we prepared TNTA by anodizing a Ti plate and decorated the TNTA with Al,Cr-codoped SrTiO₃ (STO) nanocubes through a hydrothermal treatment to enhance the PEC properties. We also prepared pristine and undoped STO-decorated TNTA for comparison. The hydrothermal treatment duration was optimized for the TNTA-STO:Al,Cr sample to achieve the best PEC performance. Finally, the possible PEC reaction mechanism was proposed based on the obtained experimental results.