Rational and scalable fabrication of high-quality WO3/CdS core/shell nanowire arrays for photoanodes toward enhanced charge separation and transport under visible light.

High-quality one-dimensional WO3/CdS core/shell nanowire arrays used as photoanodes in photoelectrochemical (PEC) cells were for the first time prepared via a rational, two-step chemical vapor deposition process. The narrow band-gap CdS shell was homogeneously coated on the entire surface of as-grown WO3 core nanowire arrays, forming coaxial heterostructures. The one-dimensional core/shell heterostructure facilitates the photogenerated electron-hole pair separation and the electron transfer from CdS to WO3 nanowires under visible light illumination. Moreover, the core nanowire arrays provide a direct pathway for the electron transport. The present results imply that the WO3/CdS core/shell heterostructure nanowire arrays may be useful in the design of nanostructure photoanodes toward highly efficient PEC cells.