Nanostructured WO₃/graphene composites for sensing NO at room temperature

Area of Science:

• Materials Science and Nanotechnology
• Chemical Engineering
• Environmental Science

Background:

• Tungsten oxide (WO3) is a promising nanomaterial for gas sensing.
• Controlling WO3 morphology is crucial for optimizing gas sensing properties.
• Capping agents play a significant role in nanomaterial synthesis and characteristics.

Purpose of the Study:

• To synthesize WO3 nanomaterials using oxalic acid and citric acid as capping agents.
• To investigate the effect of capping agents on WO3 morphology and crystal structure.
• To evaluate the gas sensing performance of WO3 and its graphene composites for NO2 detection.

Main Methods:

• Synthesis of WO3 using oxalic acid, citric acid, and CTAB.
• Characterization using XRD, FETEM, FESEM, PSD analysis, and UV-Vis spectroscopy.
• Fabrication and testing of WO3/graphene nanocomposites for NO2 sensing at various temperatures.

Main Results:

• Citric acid-assisted WO3 exhibited monoclinic phase (20 nm crystallite size), while oxalic acid-assisted WO3 showed orthorhombic phase (10 nm crystallite size).
• Citric acid-assisted WO3 demonstrated superior NO2 sensing compared to oxalic acid-assisted WO3.
• WO3/graphene nanocomposites showed enhanced sensitivity, response, and recovery times for NO2 detection.

Conclusions:

• Citric acid is an effective capping agent for synthesizing WO3 with improved NO2 sensing capabilities.
• Graphene incorporation significantly enhances the gas sensing performance of WO3.
• The developed WO3/graphene nanocomposite shows potential for efficient NO2 gas sensing applications.