TiO2 Nanowire-Supported Sulfide Hybrid Photocatalysts for Durable Solar Hydrogen Production

Abstract

As the feet of clay, photocorrosion induced by hole accumulation has placed serious limitations on the widespread deployment of sulfide nanostructures for photoelectrochemical (PEC) water splitting. Developing sufficiently stable electrodes to construct durable PEC systems is therefore the key to the realization of solar hydrogen production. Here, an innovative charge-transfer manipulation concept based on the aligned hole transport across the interface has been realized to enhance the photostability of In₂S₃ electrodes toward PEC solar hydrogen production. The concept was realized by conducting compact deposition of In₂S₃ nanocrystals on the TiO₂ nanowire array. Under PEC operation, the supporting TiO₂ nanowires functioned as an anisotropic charge-transfer backbone to arouse aligned charge transport across the TiO₂-In₂S₃ interface. Because of the aligned hole transport, the TiO₂ nanowire-supported In₂S₃ hybrid nanostructures (TiO₂-In₂S₃) exhibited improved hole-transfer dynamics at the TiO₂-In₂S₃ interface and enhanced hole injection kinetics at the electrode surface, substantially increasing the long-term photostability toward solar hydrogen production. The PEC durability tests showed that TiO₂-In₂S₃ electrodes can achieve nearly 90.9% retention of initial photocurrent upon continuous irradiation for 6 h, whereas the pure In₂S₃ merely retained 20.8% of initial photocurrent. This double-gain charge-transfer manipulation concept is expected to convey a viable approach to the intelligent design of highly efficient and sufficiently stable sulfide photocatalysts for sustainable solar fuel generation.

Keywords: CdS; In2S3; interfacial charge dynamics; photocorrosion; solar hydrogen production.