Carbon Dioxide Gas Sensor Based on Ionic Liquid-Induced Electrochemiluminescence

Electrochemiluminescence of the luminol-O-2 system in an electrolyte-free N,N-dimethylformamide (DMF)-dipropylamine (DPA) cosolution is induced by the formation of a carbamate ionic liquid (IL) from the reaction between CO2 and DPA, on the basis of which a facile ECL sensor for measuring atmospheric CO2 has been developed. This ECL sensing method shows several advantages in the detection of CO2, such as high safety, high selectivity, wide linear response range, and good sensitivity. The gas sensor was found to have a linear response range from 100 ppm to 100 v/v% and a detection limit of 80 ppm (at signal-to-noise ratio of 3). This is the first reported IL-induced ECL sensor for a gas, thus the principle of this type of sensor and the IL-induced ECL mechanism have been demonstrated in detail.