Nitrogen dioxide (NO2) gas sensor at low concentration is important as NO2 is not good to human nervous system and respiratory organs. Tungsten oxide (WO3), a popular n-type semiconductor with a band-gap of 2.6–2.8 eV, has been widely studied as a promising sensing material for determining NO2 gas because it exhibits high sensitivity, low cost of manufacturing and a fast response.

With ever-increasing demands of energy and environmental issues caused by extensive combustion of traditional fossil fuels, the quest for clean and sustainable energy sources as alternatives has attracted extensive research interest. Hydrogen seems to be a promising alternate due to its nontoxicity, ideal combustion efficiency and high gravimetric energy density. Among many accepted ways of hydrogen generation, photoelectrochemical (PEC) water splitting has been widely regarded as an appealing solution.

In the development of tungsten-based Plasma Facing Materials/Components (PFMs/PFCs), materials scientists have explored many different, innovative preparation and processing routes to meet the requirement of International Thermonuclear Experimental Reactor (ITER). Tungsten (W) is one of the best candidates for plasma-facing materials in the fusion reactors, owing to its many unique properties. However, some inherent defects such as the embrittlement, high DBTT of tungsten material restrict its application on PFMs and PFCs.

Due to the environmental pollution and climate change cause by burning of fossil fuels, finding a renewable and clean energy alternative is becoming increasingly important. Hydrogen (H2) has high energy density and zero emission, which makes it one of the most promising energy carriers in future. Among various hydrogen production methods, hydrogen evolution reaction (HER) from electrocatalytic water splitting is considered as an ideal eco-friendly strategy to generate hydrogen in a large scale.