Synergistic effect of silane and graphene oxide for enhancing the photoelectrochemical water oxidation performance of WO3NS arrays

Abstract

Photoelectrochemical (PEC) water splitting using semiconductor-based photoelectrodes is a promising approach for renewable solar fuel production. One of the biggest challenge is that semiconductor electrodes suffer from lower utilization of photogenerated-carriers and sluggish surface water oxidation reaction. Herein, we report that a novel composite photoelectrode based on silane molecule/graphene oxide being modified on the surface of well-aligned WO3 nanosheet arrays (WO3 NS/Silane/GO), efficiently harvests holes from the semiconductor and provides more reactive surface for water oxidation owing to the synergistic effect. The results demonstrate that 1.8 times photocurrent enhancement of WO3 NS/Silane/GO electrode (1.25 mA cm−2 at 1.23 V vs RHE) can be obtained compared to that of the pristine WO3 NS (0.69 mA cm−2) electrode, and it is even much higher than the photocurrent sum of WO3 NS/Silane and WO3 NS/GO electrodes. The remarkably enhanced PEC performance mainly stems from the induced external electric field (EEF) created by silane acting as hole-storage spots and the efficient carrier migration channel provided by GO, dramatically suppress the recombination of photogenerated carriers. As a result, the synergistic effect of silane and GO leads to a steady and continuous hole-transfer pathway, and promotes water oxidation kinetic by the increased reactive site quantity and activity. This study indicates that it can be a general design strategy for the preparation of efficient PEC electrodes in solar water splitting.