Applying alloyed metal nanoparticles to enhance solar assisted water splitting

Abstract

Considering hydrogen as a future fuel, development of clean approaches based on solar energy conversion is the main human challenge. Here, for the first time, TiO₂ photoanodes are decorated with Au–Ag alloy nanoparticles for efficient photoelectrochemical water splitting. The photoanodes were synthesized using a one-step co-sputtering method. The single surface plasmon resonance peak at 540 nm and also the observed shifts in photoelectron binding energies are fingerprints of homogenous alloyed nanoparticles. Scanning electron microscopy revealed the formation of nearly 40 nm particles on the surface, which was also verified by the simulation of the film's optical absorption. Photocurrent measurements showed a 30% increase in the presence of alloy nanoparticles, as well as a 50% reduction in charge transfer resistance of the electrodes. These observations are attributed to adjusting a suitable Schottky barrier in the junction of TiO₂/metal particles, which introduces applying alloy noble metallic particles as a new effective strategy for energy and environmental purposes.