Composition-optimized TiO2/CdSxSe1-x core/shell nanowire arrays for photoelectrochemical hydrogen generation

Core/shell heterostructured TiO2/CdSxSe1-x nanowire arrays (NWAs) were prepared via physical vapor deposition of CdSxSe1-x layer onto the hydrothermal pre-grown TiO2 NWAs with FTO as conductive substrate. By change the sulfur content (x) in the TiO2/CdSxSe1-x nano-composites, it was observed that the light absorption edge can be gradually tuned within a broad wavelength from 540 to 710 nm. When used as photoanodes for hydrogen generation, the as-prepared TiO2/CdSxSe1-x NWAs show much higher photoelectroncatalytic activity than the pristine TiO2 NWAs. Moreover, the TiO2/CdSxSe1-x photoelectrode with x = 0.52 exhibited the highest photocurrent level and outstanding stability, which is more suitable for long-time hydrogen generation. This study may be useful in the design of alloy hetrostructure photoelectrodes with optimal chemical composition toward the more efficient solar conversion devices.