Photoelectrochemical water oxidation through a hybrid architecture nanoparticles/nanotubes

Sunlight is the cleanest and largest source of energy, even if the sunlight is somewhat unpredictable. Indeed, photoelectrochemical (PEC) water splitting affords a clean, carbon-neutral process, even if complex, to achieve the transform of photons in chemical energy (H2). The true limitation of the process is related to the conversion in energy storage. In this work, we exploit Co-P nanoparticles and TiO2 nanotubes, and additional modifications. Using organic species, including hexane, oleylamine, and hydrazine, control of the capping ligand of the TiO2 nanotubes is achieved, allowing maximum order. Optimizing the deposition of Co-P nanoparticles, and by increasing the rate of water oxidation kinetics, the photocurrent saturated current density is improved by 1.15-fold. Additionally, a further modification at the surface of the TiO2 NTs by Ar-ion sputtering is demonstrated to improve the overall photo-saturated photocurrent density up to 1.7-fold of the TiO2 NTs deposited with Co-P nanoparticles. Finally, a further modification at the surface of the TiO2 NTs by Ar-ion sputtering is demonstrated to improve the overall photo-saturated photocurrent density.