Sensitivity enhanced, stability improved ethanol gas sensor based on multi-wall carbon nanotubes functionalized with Pt-Pd nanoparticles

Abstract

This paper reports a kind of ethanol gas sensor with enhanced sensitivity and improved stability. It utilizes multi-wall carbon nanotubes (MWCNTs) functionalized with Pt-Pd nanoparticles as catalyst. The MWCNTs with large specific surface area were used as carbon supports for the bimetallic catalyst (Pt-Pd) to enhance the electrochemical activity. The results demonstrate that the highest sensitivity (0.938 mV/ppm, which is ∼1.47 times higher than existing sensors) is realized by utilizing the catalyst with 80 wt% Pt-Pd. On the other hand, the highest value (2.877 mV/mg·ppm, ∼1.64 times higher than the reported ones) of the mass-normalized sensitivity is obtained with the 20 wt% Pt-Pd catalyst. Repeated detection of ethanol gas demonstrated a low limit of detection (LOD) of 3 ppm and a large dynamic response range from 3 to 400 ppm. The linear correlation coefficient (R2) of the signal was ≥0.998 from 0 to 400 ppm, and the performance degradation over 7 days was <2.7%, while that for existing sensors was 15%. These data illustrated that this sensor has potential applications for ethanol gas detection with high sensitivity.