Investigation of adsorption-desorption characteristics of CO and H2 on Cu2+ doped SnO2 for identifying gas components by temperature modulation

Abstract

The identification and quantification of mixed gas species have been still the research hotspot and difficulty of resistive gas sensor. In this work, Cu 2+ doped SnO 2 gas-sensing materials were prepared to quantitatively identify CO and H 2 gas mixture, and PID (Proportional-Integral-Differential) temperature control technology was combined to test the temperature modulation of gas-sensing materials more precisely. The results show that under the condition of Cu 2+ doping, the gas sensing performance for SnO 2 gas-sensing materials are improved, mainly because of the oxygen vacancy and the lattice distortion caused by doping. On the basis of this, the resistance value and the ratio of following-up time were taken as static and dynamic factors respectively to quantificationally distinguish CO and H 2 components. The resistance value and the following-up time ratio under different condition of temperature modulation were used to establish preliminarily a novel model for quantitatively determining the gas concentration, where the possibility of the composition of the two gases was first determined by the following-up time ratio, and then the gas concentration was determined by the comparison of the resistance. The simple mathematical model lays a foundation for the quantitative analysis of multicomponent gases. • Cu 2+ doped SnO 2 gas-sensing material were successfully prepared. • Effect of Cu 2+ on crystal structure and gas sensing performance was investigated. • PID technology was combined to ensure the accuracy of temperature modulation. • The dynamic and static adsorption-desorption characteristics of gas were analyzed. • A new model for quantitatively determining gas concentration is established.