NiO thin-film formaldehyde gas sensor

The suitability of both pure and Li-doped NiO as a thin-film resistive gas sensor for formaldehyde has been investigated. Pure NiO had a linear formaldehyde sensitivity of 0.825 mV ppm(-1) while that for 0.5 at.% Li-doped NiO was 0.488 mV ppm(-1) at 600 degreesC. These gas-sensing materials also showed similar sensitivity for methanol and acetone as well as a reduced sensitivity for toluene and ethanol. Chloroform was a poison for these gas-sensing materials. Due to resistive noise, the detection limit for formaldehyde was found to be approximate to 40 ppm. (C) 2001 Elsevier Science B.V. All rights reserved.