With the intensification of global warming and fossil energy crisis, people are paying more and more attention to the search for renewable clean energy. Solar energy and hydrogen energy are a kind of sustainable energy. Photocatalytic technology can convert solar energy into hydrogen energy. In recent years, the use of semiconductor materials to split water to produce hydrogen under light has always been a research hotspot.

Tungsten oxide nanomaterials have been widely studied due to their excellent gas sensitivity, photocatalysis, electrochromic and other properties. Tungsten trioxide (WO3) with nanostructures is expected to be a candidate material for gas sensors for detecting various gases (NH3, H2S, NO2, CH3OH, etc.). Tungsten oxide nanomaterials with specific size and morphology are synthesized by thermal oxidation method, hydrothermal method, electrochemical anodic oxidation method and other methods. Hydrothermal synthesis specifically shows much more advantages of more effective, low cost, easier to operate and environmentally friendly.