Dielectric nanocomposite of diphenylethylenediamine and P-type multi-walled carbon nanotube for capacitive carbon dioxide sensors

•Dielectric nanocomposite comprising P-MWCNT and a low molecular weight organic diphenylethylenediamine stabilised with an acrylate resin is designed for realizing CO2 detection at room temperature.•Small amount (0.5wt%) of P-type multi-walled carbon nanotube in DPED dramatically improves the CO2 sensitivity by ∼100 times.•Sensitivity improvement is duo to significantly improved transformation of amine to carbamate in CO2 atmosphere with the P-MWCNT. Dielectric nanocomposite comprising P-type multi-walled carbon nanotube and low molecular weight organic (1R,2R)-(+)-1,2-diphenylethylenediamine, which is stabilised with an acrylate resin, is prepared and used as a sensing layer for capacitive carbon dioxide sensor operated at room temperature. It is found that adding a small amount (0.5wt%) of P-type multi-walled carbon nanotube in diphenylethylenediamine can dramatically improve the CO2 sensitivity by ∼100 times. The P-type multi-walled carbon nanotube significantly increases the transformation rate of amine to carbamate in CO2 atmosphere as a catalyst for the chemical interactive sensing mechanism. In addition, P-type multi-walled carbon nanotube substantially improves temperature and humidity cross-sensitivities. The results show that the dielectric nanocomposite of diphenylethylenediamine and P-type multi-walled carbon nanotube is promising for capacitive carbon dioxide sensing application with ppm sensitivity at room temperature.