ZnO Hemisphere Pits Nanowire/CdS Photoelectrode for High-Efficiency Photoelectrochemical Water Splitting

In this paper, a ZnO hemisphere pits nanowire (HPW) photoelectrode is fabricated by using polystyrene (PS) nanospheres as templates, and CdS is deposited on ZnO nanowires to improve further its photoelectrochemical performance. Firstly, PS nanospheres are deposited on ZnO seed layers by air–liquid interface self-assembling method. Subsequently, ZnO HPWs are grown which effected by PS nanospheres. Finally, CdS nanoparticles were deposited on the ZnO HPWs to construct ZnO/CdS heterojunction photoanodes by successive ionic layer adsorption and reaction method. This hemisphere pits nanowires composite structure demonstrated a highly efficient photoelectrocatalytic performance with a remarkable photocurrent density of 2.27 mA cm^?2 determined at 0.8 V versus Ag/AgCl. The enhanced performance of ZnO hemisphere pits nanowires/CdS nanoparticles (ZnO/CdS) composite photoanodes originated from the enhanced light absorption in the visible region and reduced photogenerated charges recombination rate. Furthermore, compared with ordinary nanowire arrays, hemisphere pits nanowire structure can reflect light more times to facilitate light harvesting. This work exhibits the important significance in constructing photoelectrodes for photoelectrochemical water splitting and other photoelectric devices.