A review on WO3 gasochromic film: Mechanism, preparation and properties

WO3, which can change from yellow to blue when exposed to H2, is a potential material for hydrogen sensors. Compared with other kinds of hydrogen sensors, WO3 optical hydrogen gas sensor has many unique advantages. However, as a versatile material, WO3 attracts much more attention of researchers in the fields of photocatalysis, electrochromism and resistance based sensors than in the field of gasochromism and the progress in gasochromism during last 10 years is rarely systematically summarized. In this synthetic review, three mechanism models of WO3 gasochromism are introduced in detail. Then the preparation methods of WO3 gasochromic film, which can be divided to four aspects, are extensively surveyed and their advantages and disadvantages are discussed in detail. Finally, the WO3 gasochromic films with excellent performances made from different methods are summarized and the future research perspectives are presented.