Enhanced NO2 sensing performance of WO3 nanoparticles prepared with glycine

Conventional metal oxide semiconductor gas sensors are inherently limited by their dependence on high operating temperatures (200–400℃), which leads to increased energy consumption and reduced long-term device stability. To overcome these challenges, this study presents a glycine-assisted solvent evaporation synthesis route for the preparation of highly dispersible WO 3 nanoparticles. Glycine acts dually as a crystallographic modulator during nanoparticle growth and as an interfacial stabilizer, allowing for control over both particle size and oxygen vacancy concentration. Subsequent annealing removes residual glycine while preserving the optimized nanostructure. The optimized 6-WO 3 sensor synthesized using 6 mmol glycine exhibits remarkable low-temperature sensing performance, demonstrating a response value of 270.9 toward 3 ppm NO 2 at a reduced operating temperature of 120°C compared to conventional WO 3 -based counterparts while maintaining high sensitivity. Systematic characterization links this energy-efficient performance to synergistic effects between enhanced gas diffusion pathways, evidenced by a BET surface area of 20.59 m 2 /g, and precise modulation of electron depletion layers via glycine-mediated oxygen vacancy engineering. This work advances a practical paradigm for designing metal oxide semiconductor sensors that harmonize high sensitivity with operational sustainability, highlighting their transformative potential in next-generation environmental monitoring systems.