Constructing a Two-Dimensional SnWO₄ Nanosheet Array Film for Enhanced Photoelectrochemical Performance

Stannous tungstate (α-SnWO 4 ) is a promising photoanode material for photoelectrochemical (PEC) water splitting, but its practical performance is severely limited by the charge recombination problem that results from poor bulk charge transport ability. Herein, SnWO 4 with a two-dimensional (2D) sheet-like array morphology (SnWO 4 -NS) was formed to provide pathways for accelerating charge transport, which is demonstrated by the small radius of electrochemical impedance spectroscopy and a short charge transport time of intensity-modulated photocurrent spectroscopy. The carrier separation efficiency and hole collection efficiency of SnWO 4 -NS were improved to 6.84 and 40.66% compared to those (4.83 and 13.18%) of SnWO 4 without controlled morphology at 1.23 V versus the reversible hydrogen electrode. As a result, the photocurrent density increased from 0.086 to0.41 mA cm –2, and a larger amount of oxygen was obtained in the same period. This 2D morphology modification method will provide a new idea for developing α-SnWO 4 with efficient PEC performance.