Photoelectrochemical and Structural Insights of Electrodeposited CeO2 Photoanodes

Cerium dioxide (CeO2) is a promising material for photoelectrochemical applications, requiring a thorough understanding of the interplay between its properties and structure for optimal performance. This study investigated the photoelectrochemical performance of CeO2 photoanodes immobilized by electrodeposition on glass substrates, focusing on the correlation between the annealing temperature and structural, optical, and electrical changes. CeO2 coatings were obtained via chronoamperometry in an aqueous solution of 25 mM CeCl3 and 50 mM NaNO₃. The photoelectrochemical characterization included the evaluation of photoactivity, current density, stability, and recombination using linear sweep voltammetry (LSV) and chronoamperometry (CA). Charge transfer resistance, flat-band potential, and capacitance were assessed through impedance spectroscopy. The optimal annealing temperature for this material was found to be 600 °C as it resulted in the lowest charge transfer resistance and increased photocurrent, which was attributed to enhanced crystallinity and variations in the Ce3+/Ce4+ ratio.