Recent Progress in the Synthesis and Potential Applications of Two-Dimensional Tungsten (Sub)oxides

While WO3 is one of the most studied metal-oxides in bulk, it is increasingly gaining interest as a two-dimensional (2D) material as it exhibits different behaviour compared to bulk. In addition, many substoichiometric WO3-x (0 <= x <= 1) phases exist both in bulk and 2D form. These Magneli phases have different physical and chemical properties than their WO3 counterparts. By introducing oxygen vacancies, the physical and chemical properties of 2D tungsten (sub)oxide nanomaterials can be further altered. This review focuses on synthesis pathways of 2D tungsten (sub)oxides reported so far, and their subsequent use for various applications. The different stoichiometries and additional oxygen vacancies that appear in these materials, combined with their low thickness and high surface area, make them interesting candidates for gas sensing, catalytic application or in electronic devices.