1D/0D WO3/CdS heterojunction photoanodes modified with dual co-catalysts for efficient photoelectrochemical water splitting

Abstract

The semiconductor photoelectrodes with sufficient light absorption, efficient photogenerated carrier separation and fast transport is crucial for photoelectrochemical (PEC) water splitting. Herein, we firstly report the 1D/0D WO3/CdS heterojunction photoanodes modified with dual co-catalysts NiOOH and Co-Pi to realize efficient water splitting. In this quaternary photoanode, the heterojunctions restrain the recombination of photo-generated electron-hole pairs and CdS acts as a light absorber for sufficient light absorption. Besides, the amorphous dual-layer co-catalyst NiOOH (the hole storage layer) and Co-Pi (hole transfer layer) can collect and delivery the holes to the Helmholtz layer, respectively. The photoanode yields 6.4 times improved photocurrent density (2.59 mA/cm2 at 1.0 V vs RHE) in comparison with that of bare WO3 and a 300 mV negatively shifts in onset potential. Moreover, it exhibits high efficiency and persistent stability. These results reveal that heterojunctions and the synergetic effect of the dual-layer co-catalyst could effectively improve the performance for water splitting. Especially, it provides a superior way to design photoelectrodes towards PEC application.