Vertically aligned Fe2TiO5 nanorods and coupling of NiMoO4/CoMoO4 as a hole-transfer cocatalyst for enhancing photoelectrochemical water oxidation performance†
Abstract
Fe2TiO5, a promising photoanode material for photoelectrochemical (PEC) water splitting, is limited by its poor conductivity and short carrier diffusion length. Herein, a novel Fe2TiO5 nanorod photoanode coated with a cocatalyst NiMoO4/CoMoO4 has been designed for efficient PEC water splitting. The Fe2TiO5/NiMoO4/CoMoO4 photoanode shows a photocurrent density of 1.67 mA cm−2 at 1.23 V versus the reversible hydrogen electrode (RHE) under an irradiation of 100 mW cm−2, which is 2.25 times that of Fe2TiO5 nanorods (0.74 mA cm−2) at 1.23 V versus RHE. And the onset potential of Fe2TiO5/NiMoO4/CoMoO4 illustrates a 247 mV cathodic shift from that of the Fe2TiO5 nanorod photoanode. Moreover, Fe2TiO5/NiMoO4/CoMoO4 exhibits excellent stability at 1.23 V versus RHE under 2 h illumination. Further investigation indicates that NiMoO4/CoMoO4 modifies the surface states of Fe2TiO5 nanorods and effectively promotes the reaction kinetics at the semiconductor/electrolyte interface. This work emphasizes that the design of a nanorod structure and the loading of a cocatalyst provide a novel strategy for achieving excellent PEC performance.