Rf sputtered SnO2 nano-thin film based sensor structures integrated with various metal oxide catalysts (WO3, TeO2, NiO and Al2O3) have been exploited for trace level detection of NO2 gas at lower operating temperature. Metal oxide catalysts were dispersed in the form of nano-thin micro-discs (8 nm thickness and 600 micrometer diameter) over SnO2 and gas sensing characteristics have been studied towards NO2 gas as a function of temperature. SnO2 sensor structure with WO3 micro-discs showed a drastic increase in sensor response (~5.4x10^4) as compared to other catalysts at a relatively low operating temperature (100 ◦C) with a fast response time of ~62 sec and recovery time of ~15 min towards 10 ppm of NO2 gas. Such an improvement in the sensing response, response time and recovery time could be attributed to the spill-over of sensing gas molecules over the uncovered surface of SnO2 thin films by WO3 micro-discs catalyst.