摘要：Health and safety considerations of room occupants in enclosed spaces is crucial for building management which entails control and stringent monitoring of CO 2 levels to maintain acceptable air quality standards and improve energy efficiency. Smart building management systems equipped with portable, low-power, non-invasive CO 2 sensing techniques can predict room occupancy detection based on CO 2 levels exhaled by humans. In this work, we have demonstrated the development and proof-of-feasibility working of an electrochemical RTIL- based sensor prototype for CO 2 detection in exhaled human breath. The portability, small form factor, embedded RTIL sensing element, integrability with low-power microelectronic and IOT interfaces makes this CO 2 sensor prototype a potential application for passive room occupancy monitoring. This prototype exhibits a wide dynamic range of 400–8000 ppm, a short response time of ~10 secs, and a reset time of ~6 secs in comparison to commercial standards. The calibration response of the prototype exhibits an R 2 of 0.956. With RTIL as the sensing element, we have achieved a sensitivity of 29 pF/ppm towards CO 2 at ambient environmental conditions and a three times greater selectivity towards CO 2 in the presence of N 2 and O 2 . CO 2 detection is accomplished by quantifying the capacitance modulations arising within the electrical double layer from the RTIL- CO 2 interactions through AC- based electrochemical impedance spectroscopy and DC- based chronoamperometry.
