Effect of Calcination Temperature on NO2 Sensing Properties for Quantum Size ZnO Crystals

Quantum size ZnO crystals have been synthesized successfully by a room temperature sol-gel process using oleic acid (OA) as capping agent to control the particle size. The particle size and structure of ZnO nanocrystals have been charactirized by X-ray diffraction (XRD), transmission electron microscope (TEM) and Raman spectra analysis methods. The sensor based on ZnO powder calcined at 400 degrees C for 1 h exhibits the highest response of 280 to NO2 and the selectivity to CO and CH4 at the same concentration reaches 31 and 49 at operating temperature of 290 degrees C. The effect of calcination temperature on the performance of gas sensing has also been studied.