Enhanced Photoelectrochemical Water Splitting Performance of Ce-Doped TiO2 Nanorod Array Photoanodes for Efficient Hydrogen Production

In this study, original titanium dioxide (TiO2) and cerium (Ce)-doped TiO2 nanorod array photoanodes are prepared by hydrothermal method combined with high-temperature annealing, and their morphology, photoelectrochemical properties, and photocatalytic hydrogen production ability are systematically evaluated. X-ray diffraction (XRD) analysis shows that as the Ce content increases, the diffraction peak of the rutile phase (110) shifts towards lower angles, indicating the successful doping of different contents of Ce into the TiO2 lattice. Photoelectric performance test results show that Ce doping significantly improves the photocurrent density of TiO2, especially for the 0.54wt% Ce-doped TiO2 (denoted as CR5). The photocurrent density of CR5 reaches 1.98 mA/cm2 at a bias voltage of 1.23 V (relative to RHE), which is 2.6 times that of undoped TiO2 (denoted as R). Photoelectrochemical hydrolysis test results show that the hydrogen yield performance under full-spectrum testing conditions of Ce-doped TiO2 photoanodes is better than that of original TiO2 as well, which are 37.03 and 12.64 µmol·cm−2·h−1 for CR5 and R, respectively. These results indicate that Ce doping can effectively promote charge separation and improve hydrogen production efficiency by reducing resistance, accelerating charge transfer, and introducing new electronic energy levels. Our findings provide a new strategy for designing efficient photocatalysts with enhanced photoelectrochemical (PEC) water-splitting performance.