(390a) A Microfabricated Carbon Dioxide Sensor for Portable Applications

The reliable detection of carbon dioxide emissions is a key step towards the ability to mitigate CO2 levels in the atmosphere. At present, many CO2 sensors exist in the literature. Mixed oxide capacitors work very well, but require watts of power to maintain the sensor at the operating temperatures, typically 400-500 C. Infrared CO2 sensors also work well, but the lasers usually require a few hundred milliwatts of power to give reliable results. Such sensors are quite useful when attached to the power grid, but they do not provide the possibility of a long term portable unattended CO2 sensor. In this paper we present a new design for a microfabricated CO2 sensor that operates at room temperature, with very low power input. The device uses the selective adsorption of CO2 in a room temperature ionic liquid followed by an electrocatalytic reaction to detect CO2. We find that the device is able to measure normal atmospheric levels of CO2 with high reliability using less that 10 microwatts of power. This advance will enable a new class of portable CO2 sensors to be constructed.