Controllable TiO2 core-shell phase heterojunction for efficient photoelectrochemical water splitting under solar light

In this study, hydrogenated TiO2 anatase/rutile phase heterojunction is fabricated and used for photoelectrochemical water splitting to generate clean H-2 energy under solar light. This TiO2 phase heterojunction photocatalyst material with core-shell structures is accurately prepared by a hydrothermal method to grow the core of ruffle TiO2 nanorod arrays and an ALD technology to form the shell of the anatase TiO2 layer with a controllable thickness, followed with a hydrogenated treatment to introduce some disordered structures and oxygen vacancies to the TiO2 phase heterojunction. This new structured TiO2 photocatalyst material yields a high photocurrent density of 3.88 mA cm(-2) at 1.23 V-vs.RHE under simulated solar light (100 mW cm(-2)) with a maximum IPCE of 59.7% at the wavelength of 380 nm. These values are almost 3.8 and 7.4 times higher than that of the bare ruffle TiO2, respectively. The enhanced photoelectrochemical performances are mainly attributed to the synergistic effect of the core-shell phase heterojunction, highly ordered structure and post-hydrogenated treatment to accelarate the separation and transmission of the photogenerated electrons and holes. This hydrogenated TiO2 core-shell phase heterojunction indicates promising potential applications in the fields of photoelectrocatalysis and photovoltaic devices under solar light.