Sensing of n-Butanol Vapours with Oxygen Vacancy-Enriched Zn2SnO4-SnO2 Hybrid-composite

Abstract

The precise identification of various toxic gases is important to prevent the health and environmental hazards using cost effective, efficient metal oxide based chemiresistive sensing method. This study explores the sensing properties of a chemiresistive sensor based on a Zn2SnO4-SnO2 nanocomposite for detecting n-butanol vapours. The nanocomposite, enriched with oxygen vacancies, was thoroughly characterized, confirming its structure, crystallinity, morphology and elemental composition. The sensor demonstrated high repeatability across the temperature range of 275-350 °C and concentrations from 100-1000 ppm, with the highest response observed at 350 °C. The response time increases as the concentration of n-butanol increases. The conductance transients were modelled using the Langmuir-Hinshelwood mechanism, showing temperature-dependent oxidation kinetics. At lower temperatures, the rate-determining step involved n-butanol oxidation, while at higher temperatures, simultaneous oxidation and desorption processes dominated. The calculated activation energy for n-butanol oxidation step was 0.12 eV. Furthermore, Principal Component Analysis (PCA) effectively discriminated between different n-butanol concentrations, emphasizing the sensor's potential for selective n-butanol detection through a combination of kinetic modelling and statistical analysis.