Effects of Niobium-Loading on Sulfur Dioxide Gas-Sensing Characteristics of Hydrothermally Prepared Tungsten Oxide Thick Film

Table 1

A summary of the gas-sensing properties of WO₃-based gas sensors towards SO₂.

Authors/reference	Method	Materials	Gas concentration	SO2 sensing performances
Shimizu et al., 2001 [9]	Pyrolysis/paste casting	Unloaded WO3	800 ppm	Response: ~12 to 800 ppm at 400°C
	Pyrolysis/impregnation/paste casting	1.0 wt% Ag/WO3	800 ppm	Response: ~20 to 800 ppm at 450°C
Tomchenko et al., 2003 [10]	Drop casting	WO3	25 ppm	Response: ~1.3 to 25 ppm at 200°C
Stankova et al., 2004 [11]	RF magnetron sputtering	Pt/WO3	1 ppm	Response: ~6 to 1 ppm at 200°C, 50 m of electrode gap
Matei Ghimbeu et al., 2010 [12]	Electrostatic spray deposition	Unloaded WO3	20 ppm	Response: ~3 to 20 ppm at 350°C
Boudiba et al., 2012 [13]	Hydrothermal/screen-printing	WO3 thick films	1–10 ppm	Response: <2 to 10 ppm at 260°C
This work	Hydrothermal/spin coating	0.5 wt% Nb-WO3	25–500 ppm	Response: ~10 to 500 ppm at 250°C