An electrochemical study of lignin films degradation: Proof-of-concept for an impedimetric ozone sensor

Impedimetric and cyclic voltammetric studies of lignin degradation and the potential use of lignin-modified glassy carbon electrodes as transducers for ozone are described. The proposed approach is based on the degradation of lignin films caused by the reaction with ozone, which results in changes of faradaic impedance of the sensor electrodes in the presence of ferricyanide species as a redox probe. The effect of ozone on the lignin films was also examined by HATR-FTIR spectroscopy and scanning electron microscopy. Optimization of several experimental parameters such as the solvent of lignin, the lignin loading, the thickness of the coating and the reaction medium, is demonstrated. Exposing the sensor electrodes to various ozone concentrations resulted in proportional changes in the charge transfer resistance.