Recent progress in the development of tin tungstate (α-SnWO₄) photoanodes for solar water oxidation

Direct water splitting in a photoelectrochemical device is a promising approach to store solar energy in the form of green hydrogen. However, its implementation has been hindered by a classic technological dilemma: high efficiency values have only been demonstrated with devices containing expensive and scarce materials, while devices based on low-cost and abundant materials have only shown limited efficiencies. In order to overcome this limitation, novel photoelectrode materials that are Earth-abundant and highly efficient would be needed. This review article summarizes recent efforts in developing tin tungstate (α-SnWO₄) as a promising photoanode material for solar water oxidation. Various synthetic procedures and modification strategies attempted on α-SnWO₄ photoanodes in the past decade, resulting in an impressive two-orders of magnitude improvement of its photoelectrochemical performance, are presented. Finally, the remaining major limitations of the material are discussed, and suitable strategies to overcome them and continue pushing the photoelectrochemical performance toward the theoretical maximum level are proposed. © 2023 The Royal Society of Chemistry.