Stannous Tungstate Semiconductor for Photocatalytic Degradation and Photoelectrochemical Water Splitting: A Review

Abstract

The use of photocatalysis and photoelectrocatalysis is expected to achieve the efficient utilization of solar energy to alleviate and even solve the problems of energy depletion and environmental pfollution. At present, stannous tungstate materials have attracted extensive attention in the fields of photocatalysis and photoelectrocatalysis as favorable candidates for such utilization because of their narrow band gap energy (which is~1.7 eV for the α phase and ~2.7 eV for the β phase, respectively) and unique band structure (which covers the oxidation and reduction potential of water). However, their practical application is still limited by excessive electron–hole recombination and poor stability. In this review, basic information (crystal and electronic structures) related to photocatalysis and photoelectrocatalysis is presented. Additionally, various strategies to enhance the photocatalytic and photoelectrochemical properties of stannous tungstate materials, such as morphological modification, crystal facet engineering, doping modification, and multicomponent compositing, are summarized. Furthermore, the achievements and difficulties of the relevant studies are discussed. The information presented in this review can provide a reference for subsequent research on the photocatalytic and photoelectrochemical performance of tungstate-based materials.

Development of ABO4‐type photoanodes for photoelectrochemical water splitting

“…During the PEC reaction process, the carrier diffusion length of SnWO 4 is relatively short, and recombination is easy to occur, resulting in poor PEC performance (~1.0 mA cm −2 vs. theoretical 17 mA cm −2 at 1.23 V vs. RHE). 296 In addition, since Sn in SnWO 4 is positively divalent, SnWO 4 is easily oxidized…”

“…Despite its theoretically remarkable PEC properties, SnWO 4 has unavoidable drawbacks. During the PEC reaction process, the carrier diffusion length of SnWO 4 is relatively short, and recombination is easy to occur, resulting in poor PEC performance (∼1.0 mA cm −2 vs. theoretical 17 mA cm −2 at 1.23 V vs. RHE) 296 . In addition, since Sn in SnWO 4 is positively divalent, SnWO 4 is easily oxidized (SnWO 4 + H 2 O + 2H + → SnO 2 + WO 3 + 2H + ), and the arising poor stability and high photocorrosion limit its practical applications.…”