Photoelectrochemical water oxidation over TiO₂ nanotubes modified with MoS₂ and g-C₃N₄

TiO₂ nanotube arrays (TNAs) have been studied for photoelectrochemical (PEC) water splitting. However, there are two major barriers of TNAs, including a low photo-response and the fast charge carrier recombination in TNAs, leading to poor photocatalytic efficiency. Through a comparison of MoS₂/TNAs and g-C₃N₄/TNAs, it was found that TNAs modified with MoS₂ and g-C₃N₄ exhibited a current density of, respectively, 210.6 and 139.6 μA·cm^-2 at an overpotential of 1.23 V vs RHE, which is 18.2 and 12 times higher than that of pure TNAs under the same conditions. The stability of the MoS₂/TNAs heterojunction is higher than that of g-C₃N₄/TNAs.