Facile Screen-Printed Carbon Nanotube Electrode on Porous Substrate with Gold Nanoparticle Modification for Rapid Electrochemical Gas Sensing

Gas sensors have attracted extensive attentions due to their vital roles in various applications. However, gas sensors featuring long lifetime, fast response and low cost still remain challenging. This paper presents a facile screen-printed carbon nanotube electrode on porous polytetrafluoroethylene (PTFE) with room temperature ionic liquid (RTIL) for rapid gas sensing. Screen printing technique was implemented on porous PTFE substrate to form three-electrode system using carbon nanotube ink and silver ink. Thus, gases can directly diffuse through the porous substrate rather than supporting electrolyte for rapid detection. RTIL was utilized as the supporting electrolyte that ensures long sensor lifetime. With gold nanoparticles modification, the sensor exhibited enhanced electrochemical performance for gas detection. Chronoamperometry was conducted to evaluate the sensor performance from 2.1% oxygen to 12.6% oxygen, validating good sensitivity and linearity. The sensor also presented good repeatability, stability and reproducibility in the tests. Due to the unique porous substrate of the sensor, the response time can be as low as similar to 14 s that achieves rapid oxygen sensing. In summary, the sensor was validated with satisfactory performance, which is promising for wearable gas sensing and acute gas exposure alerting.