Au–Decorated TiO₂ Nanoparticle Photoanode: Synthesis, Structural, Optical Properties and Photoelectrochemical Water Splitting Performance

This study presents a novel approach to synthesizing Au-decorated TiO 2 (Au/TiO 2 ) nanoparticles (NP) using a spin-coating method, showcasing significant advancements in photoanode development. The resulting Au/TiO 2 NPs exhibit well-defined crystallite structures comprising Au and TiO 2 phases, featuring Au NP sizes ranging from 2.61 nm to 6.10 nm. Notably, the energy bandgap of these Au-decorated TiO 2 NPs demonstrates a discernible redshift of 3.22–3.02 eV across various Au concentrations (1%–20%). Photoluminescence spectra reveal three distinct emission peaks at room temperature in the 400–550 nm wavelength range. The water-splitting activity of the Au/TiO 2 NPs is investigated through the photoelectrochemical cell (PEC) employing an electrolyte solution with 1.0 M KH 2 PO 4 /K 2 HPO 4 buffer. The results demonstrate a substantial photocurrent density of 0.23 m A .cm –2 at a potential of 1.6 V (versus RHE ) and a photoconversion efficiency of 0.1% at 0.52 V ( vs . RHE ), respectively. This pioneering study underscores the potential of Au/TiO 2 NP photoanodes as key components in advancing sustainable energy technologies, particularly in the realm of efficient PEC water-splitting applications.