The chlorinated phenoxyacetic acid herbicide 2,4-D is extensively used for control of broadleaf weeds in cereal crops. It has been used for weed control on wheat, barley, oats, rice, maize and raps crops and is typically applied to cereals at a rate (active ingredient) of 0.5 kg ha−1. 2,4-D is potentially dangerous to both animals and humans and is a well-known endocrine disruptor.

In photoelectrochemical (PEC) water splitting, hydrogen is produced from water using sunlight and specialized semiconductors called photoelectrochemical materials, which use light energy to directly dissociate water molecules into hydrogen and oxygen. Hydrogen is the most promising clean energy source with very high gravimetric energy density and environmental friendliness.

Tungsten trioxide (WO3) is a common n-type semiconductor. WO3 has a wide bandgap semiconductor between 2.5–3.6 eV, which makes being widely used in the fields of catalysis, photocatalytic and electro-chromic systems to produce smart windows, chemical sensors for detection of polluting gases such as H2S, NOx, NH3, and monitoring H2 gas concentration to ovoid explosions in embedded system. WO3 has the advantages of structural polymorphism, chemical stability, and good biocompatibility It is Hexagonal tungsten trioxide (h-WO3) possesses an open-tunnel structure and exhibits intercalation chemistry and other favorable properties, which has been used for lithium batteries, optoelectronic device, and ion exchanger.

Transitional metal oxides (TMO) such as ZnO, CuO, CdO, TiO2, and NiO had been widely applied in the field of gas sensing. Tungsten trioxide (WO3) is one of the n-type semiconducting TMO materials which possess fantastic properties such as wide band gap, thermal stability and surface-active sites. The WO3 nanomaterials also studied for various applications viz photocatalysts, photoelectrode, photochromism. The WO3 with various morphologies such as cauliflower, thin film, nanosheets and nano-spherical particles have been utilized for gas sensing. Nanosized WO3 is very sensitive toward reducing and oxidizing gas such as ethanol and Nitrogen dioxide (NO2).