Novel synthesis of ternary nanocomposites with β-SiC fibers, SnO2, and In2O3 for atmospheric gas sensing under high temperature conditions

Abstract

A gas sensing test was performed by using a SCISO nanocomposite under various temperature conditions. The gas sensing test indicated that the introduction of SnO₂ onto β-SiC-In₂O₃ nanocomposites successfully improved the sensing ability by an effective surface reaction between the electrode and detector gas. The physical properties of the nanocomposites were analyzed by XRD, SEM, EDX, TEM, and HR-TEM. The chemical bonding states and the symmetric motions of the prepared nanocomposites were analyzed by XPS and Raman spectroscopy. The excellent electronic conductivity and chemical activity obtained in SCISO nanocomposites change the usability level of the β-SiC fiber and the previously studied β-SiC-In₂O₃ nanocomposite. SCISO105 NCs showed high resistivity and a quite strong response for CO₂ gas at room temperature while showing a low response for O₂ gas. Under high temperature (600 °C) conditions, the sensor showed a strong response to O₂ gas, with a low response to CO₂ gas. In addition, the CH₄ gas sensing test was conducted on sensor electrodes; among them, SCIS105 showed the best response to CH₄ in different temperature environments. The sensing test found a correspondence between the molecular structure of the gases and the chemical structure of the sensor. Gas sensor tests have shown that temperature fluctuations, gas chemical formulae, surface reactions between the sensor surface and the gas, and the electron receiver/donor phase are all factors that determine the precise state. The electron density of the sensor layer and the effective charge transfer and separation properties of the β-SiC-In₂O₃–SnO₂ nanocomposites provided a better sensing ability under different high-temperature variations; meanwhile, the loading of MOs improved the usability of the β-SiC fiber.