Sensitivity and selectivity of metal oxides based sensor towards detection of formaldehyde

This paper presents the fabrication and characterization of metal oxides based sensor for detection of formaldehyde gas. Three different metal oxides are considered (i.e. TiO2, ZnO and SnO2) as transducer for the optimum sensitivity and selectivity detection. The metal oxides are deposited on the top on aluminum/glass substrate using sol-gel technique. Comparison performance has been made and found that SnO2 gives better sensitivity detection of formaldehyde molecule as compared with TiO2 and ZnO. At this stage, the test validation is done by dipping the electrode in 100 ppm formaldehyde liquid solution. Further, we show that SnO2 provides better selectivity toward the detection of formaldehyde and compared to acetone, ethanol, formaldehyde, isopropanol and methanol. Lastly, we demonstrate that, our sensor capable to detect down to 0.010 ppm of formaldehyde liquid. This excellent capability is achieved due to good uniformity and high surface-to-volume (approximately 70 nm) of SnO2 surface morphology characterized by using AFM.