Cost-effective fabrication of nanostructured zinc oxide based electrodes for photoelectrochemical water splitting

In this study nanostructures of the zinc oxide (ZnO) photoelectrodes were synthesized via facile chemical bath deposition. Effects of the seed layer on the ZnO nanowire formation and the photoelectrochemical (PEC) properties have been investigated. Also silver (Ag) nano-islands were deposited on top of ZnO nanofilms to localize the photon absorption at the surface. Photoelectrochemical (PEC) measurements indicated that the ZnO nanowire arrays and ZnO-Ag nanostructures enhanced the short circuit current (Jsc) and the open circuit potential (Eaoc). Therefore, the solar-to-hydrogen efficiency increased drastically. The highest Eaoc and Jsc of 840 mV and 208 μA/cm2 have been observed for the silver deposited ZnO nano-film photoelectrodes. The possible mechanisms enhancing the charge separation and transportation during the PEC water splitting by means of nano-structured ZnO electrodes have been investigated via morphological, optical and electrical measurements.