{202}‐Dominated WO <sub>3</sub> Nanosheet Arrays Boosting Hole Transport for Efficient Photoelectrochemical Water Oxidation
Youheng Yao, Yongli Li, Jinshu Wang, Yunfei Yang, Junshu Wu, Wenyuan Zhou, Jiawei Xiao, Meng Xu
Abstract
Abstract Metal oxide photoanodes with exposure of specific facets generally exhibit distinct photoelectrochemical (PEC) performances; however, the critical role of facet‐dependent hole transport in determining the overall efficiency remains underexplored. Herein, a high‐performance WO 3 photoanode is presented via a seed‐mediated epitaxial growth strategy, featuring well‐built nanosheet arrays with high percent {202} facets. Comparative studies reveal that a 320% increase of hole mobility along {202} facets relative to {200} ones, serves the trigger of efficient carriers' separation. Owing to this “hole highway” effect, {202}‐dominated WO 3 photoanode exhibits significantly enhanced PEC efficiency with excellent stability, delivering a remarkable photocurrent density of 3.87 mA cm −2 at 1.23 V RHE under AM 1.5G illumination, which reaches 96.8% of the theoretical maximum for the WO 3 photoanode. First‐principles calculation combined with characterizations further manifest the lowered activation energy barrier for fast water oxidation kinetics on {202} surface with tetra‐coordinated W atomic configuration. Particularly, it promotes the rate‐determining step (O * → OOH * ) in oxygen evolution reactions (OER), and minimizing the accumulation of O * intermediates. This work proposes a novel design concept for facet‐control of semiconductors, and establishes a viable pathway to develop efficiently solar‐driven water splitting.