Gas Sensing Properties and Mechanism of Nano‐SnO₂‐Based Sensor for Hydrogen and Carbon Monoxide

Abstract

Nano‐SnO 2 powder was prepared by the hydrothermal method in this paper. X‐ray powder diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the composition of the crystalline phase and the morphology of the prepared gas‐sensitive materials, respectively. In particular, the study focused on the sensing behaviors of nano‐SnO 2 ‐based sensor towards power transformer fault gases such as hydrogen and carbon monoxide. The optimum working temperature for hydrogen and carbon monoxide is about 400 ∘ C and 360 ∘ C, separately. Further investigations into the adsorption process of gas molecule on SnO 2 (110) surface based on the first principles were conducted. The calculations indicated that 1 σ orbits of H 2 split into several new electronic peaks and 5 σ orbits of CO almost degenerated completely in the adsorption process, which promoted charge transfer between gas molecule and SnO 2 (110) surface. It provides a qualitative explanation for the prepared nano‐SnO 2 ‐based sensor exhibiting different gas sensing properties towards H 2 and CO.