Raspberry-like Gold Nanoparticle-Decorated Titania Nanorods for Plasmon-Enhanced Photoelectrochemical Oxygen Evolution

The development of efficient photoelectrochemical (PEC) water splitting systems for the oxygen evolution reaction is essential for realizing sustainable hydrogen fuel production. Among the various strategies for enhancing PEC cell performance, plasmonic nanostructures, particularly gold nanoparticles, have emerged as highly promising candidates for improving the efficiency of photoanodes. Herein, we report the fabrication of a photoanode architecture consisting of raspberry-like gold nanoparticles (Au RLNPs) incorporated into hydrothermally synthesized TiO₂ nanorod arrays on a fluorine-doped tin oxide substrate (Au RLNP/TiO₂||FTO) for PEC water splitting application. The Au RLNPs, synthesized via a facile, single-step solution-phase approach, exhibit a distinctive morphology that gives rise to a significantly red-shifted surface plasmon resonance, thereby enhancing visible light harvesting and promoting charge carrier generation. As a result, the Au RLNP/TiO₂||FTO photoanode demonstrates a remarkable photocurrent density of 2.18 mA·cm^–2 at 1.23 V_RHE under AM 1.5G illumination. These findings underscore the substantial potential of the unique photoanode architecture for advancing the development of high-performance PEC water splitting systems.