Photocatalytic Efficiency of Cerium Dioxide Hollow Spheres Sensitized with Bimetallic Au-Pd Nanoparticles for Enhanced Hydrogen Evolution.

CeO2 with a hollow sphere morphology and a surface sensitized with gold (Au) and palladium (Pd) nanoparticles (NPs) was investigated as a photocatalyst for solar-driven hydrogen (H2) production. Structural characterization by X-ray diffraction (XRD) and morphological analysis by scanning electron microscopy (SEM) confirmed the successful synthesis of the materials and revealed that no significant structural alterations occurred in the CeO2 support following the surface modification procedures. Raman spectroscopy revealed a shift in the characteristic vibrational band of CeO2 upon sensitization with metallic NPs, which was attributed to the generation of oxygen vacancies within the oxide lattice. The surface modification of the hollow CeO2 spheres with metal NPs, exhibiting an average particle size of 6.38 ± 0.08 nm, contributed to an enhanced absorption of visible light and a concomitant increase in photocatalytic H2 evolution. The modified photocatalysts demonstrated improved performance due to both the tailored morphology of the support, achieving an activity of 19.9 μmol∙g-1∙h-1, and its sensitization with metallic NPs, which further elevated the H2 production rate to 45.4 μmol∙g-1∙h-1. These findings underscore the potential of combining morphological control with strategic chemical modification as an effective approach for the design of high-performance photocatalysts for solar H2 generation.