Au-Deposited Ce_0.5Zr_0.5O₂ Nanostructures for Photocatalytic H₂ Production under Visible Light

Pure Ce0.5Zr0.5O2 and Au (0.1-1.0 wt.%)-deposited Ce0.5Zr0.5O2 nanomaterials were synthesized via hydrothermal and non-aqueous precipitation methods using gold acetate as a chloride-free Au precursor. The synthesized nanostructures exhibited enhanced photocatalytic activity for hydrogen production via aqueous bioethanol photoreforming under visible light. Different characterization tools such as powder XRD, HRTEM, FT-IR, DR UV-vis, XPS and N-2 gas adsorption were used to analyze the physicochemical properties of the synthesized photocatalysts. The band gap value was lowered from 3.25 eV to 2.86 eV after Au nanoparticles were deposited on the surface of Ce0.5Zr0.5O2. The 1.0 wt.% Au-deposited Ce0.5Zr0.5O2 sample exhibited the highest photocatalytic activity for H-2 production (3210 mu mol g(-1)) due to its low band gap, the presence of more oxygen vacancies and its porous character. The EIS results reveal that the deposition of 1.0 wt.% Au nanoparticles is responsible for the highest charge separation efficiency with an increased lifetime of photogenerated e(-)/h(+) species compared to the other samples. In addition, the presence of plasmonic Au is responsible for the effectiveness of the electron trap in improving the rate of H-2 formation.