Potential of copper oxide thin film-based sensor probe for carbon dioxide gas monitoring

An economical and portable gas-sensing prototype was developed for CO2 gas monitoring of flue gas. The effectiveness of the prototype was demonstrated with a CuO metal oxide–semiconductor thin-film sensor prepared by a modified sol–gel process. Gas concentrations of 0.8–4% were generated by a chemical reaction to mimic the large concentrations of CO2 in flue gas from industrial power plants. The fabricated prototype showed high sensitivity to the tested gas and was operable within a varied temperature range of room temperature up to 350 °C. CuO thin film exhibited a good response (~ 20%) to 8354 ppm CO2 gas with a response time of ~ 5 s at 300 °C. The dominant gas-sensing mechanism was found to be the formation of carbonates on the CuO surface.