Synergistic effects of nano-structured WO3-Se heterojunction decorated by organic Nafion layer on improving photoelectrochemical performance

Abstract

Exploration of high-performance photoanodes is considered as an essential challenge in photoelectrochemical (PEC) water splitting due to the complex four-electron reaction in water oxidation. Herein, the nano-structured WO3-Se heterojunction decorated by organic Nafion layer is designed. The optimized WO3-Se200-0.05Nafion photoanode shows a remarkable photocurrent of 1.40 mA cm−2 at 1.23 V versus reversible hydrogen electrode, which is 2.5-fold higher than that of pure WO3 nanosheets (WO3 NS) photoelectrode. Remarkably, the photocurrent increments of WO3-Se200-0.05Nafion is larger than the increment sum of WO3-Se200 and WO3-0.05Nafion, which affirming the synergistic effect of Se nanospheres and Nafion layer. The improved PEC performances are attributed to the quick charge separation and transfer, the increased electric conductivity, and the excellent kinetics of oxygen evolution, which is derived from the strong interaction among WO3, Se and Nafion. Meanwhile, the better visible-light harvesting from Se nanospheres as photosensitizer and the induction of transparent Nafion as a passivation layer can explain this synergy. It hopes this heterostructure design with organic Nafion decoration can inspire to exploit outstanding performance photoanodes for PEC water splitting.