Coral-Like CuxNi(1−x)O-Based Resistive Sensor for Humidity and VOC Detection

Chemoresistive toxic gas sensors nowadays are being used exhaustively for maintaining healthy air quality. In this paper, we report synthesis of ordered hierarchical CuxNi(1-x)O nanostructure (average diameter of (400-600 nm))-based sensing layer for chemoresistive toxic gas sensing application. The selectivity of the sensor was found to be temperature tunable. It was sensitive to humidity (response 212% with 90% RH) at room temperature and volatile organic compounds (VOCs) [response towards Ethanol (28%), Methanol (34%), Acetone (25%), and Toluene (44%) at 550 ppm] at 300 °C. The cross sensitivity of the device for VOCs at 300 °C was addressed by performing a low computationally complex clustering technique to define the zone of clear selectivity for each VOC. It was also observed that on sampling the continuous signal with Fast Fourier Transform increases the clustering efficiency by removing the background noise from the sensing transients. The response and recovery times of the sensor (for all analytes) ranged in tens of seconds with good repeatability and stability. Thus, the sensor device so fabricated is expected to serve as a commercially viable temperature tunable and selective gas sensor.