The Principle of Detect SO2 Concentration by Using the Electrochemical Method in Ionic Liquid

The reduction of SO2 with different concentrations at a platinum microelectrode was investigated by cyclic voltammetry (CV) in 1-(butyl)-3-methylimidazolium hexafluorophosphate ([Bmim]PF6). We speculated that the reaction mechanism of reduction may form a macromolecular complex, and the higher the concentration of SO2, the larger the molecular weight of the complex. The higher the concentration of SO2, the greater the diffusion coefficient of SO2 in [Bmim]PF6. There is a good quadratic function relationship between the reduction peak current and SO2 concentrations in the range from 2% to 100%, which promises a kind of ionic liquid electrolyte for the detection of SO2 gas with a wide range of concentrations.