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. (C) 2014 AIP Publishing LLC.