Self-heated Ag-decorated SnO2 nanowires with low power consumption used as a predictive virtual multisensor for H2S-selective sensing

Abstract

Multisensor systems with low-power consumption are emerging for the Internet of Things. In this work, we demonstrate the use of self-heated networked Ag-decorated SnO₂ NW sensors integrated into a portable module for selective detection of H₂S gas at low power consumption, and the integrated system is simulated as a virtual multisensor under varying heating powers for identifying and quantifying different reducing gases. The H₂S gas-sensing characterisations at the different self-heating powers of 2-10 mW showed that the gas response significantly increased with the increase in Ag density decoration and the heated power strongly affected the gas-sensing performance and sensor stability. Excellent response of 21.2 to 0.5 ppm H₂S gas was obtained at a low heating power of 2 mW with an acceptable response/recovery time of 18/980 s. The increase of the heating power over 20 mW can destroy the devices. The integrated system could selectively detect H₂S at the heating power below 4 mW and H₂, C₂H₅OH and NH₃ gases at the heating power upon 4 mW. The virtual multisensor could discriminate qualitatively (with an accuracy of 100%) and quantitatively H₂S, H₂, NH₃, C₂H₅OH (Ethanol) and CH₃COCH₃ (Aceton) gases with average errors of 13.5%, 14.7%, 16.8%, 16.9%, and 14.8%, respectively. The proposed sensing platform is a promising candidate for selective detection of H₂S gas and virtual multisensor with low power consumption for mobile or wireless network devices.

Keywords: H(2)S gas; Nanojunctions; Networked nanowires; Self-heated sensor.