High-efficiency photoelectrochemical properties by a highly crystalline CdS-sensitized ZnO nanorod array.

A ZnO nanorod array with comparatively long nanorods was successfully prepared on a Ti substrate by applying a hydrothermal method twice. CdS nanoparticles with high crystallinity were deposited onto the surface of ZnO nanorods through a galvanostatic electrodeposition method. CdS-sensitized ZnO nanorod arrays after being hydrothermally grown twice with the second growth time of 6 h possessed the best photoelectrochemical performance. The photoinduced current densities at a 0 V bias potential are 23.7 and 15.8 mA·cm(-2) under the illumination of simulated sunlight and visible light, respectively. The monochromatic incident photon-to-electron conversion efficiency values at the wavelength of 380-520 nm are in the range of 50-60%, which indicated its high photoelectric conversion efficiency. The contribution from visible light is significantly higher than that from UV light. The prepared photoanodes in the present work exhibit a potential application in photoelectrochemical hydrogen production from water reduction under sunlight.