One of the key application areas of electrochemistry is in the field of Sensors. There have been several different gas sensors developed using electrochemical principles. The sensors can either be potentiometric, meaning measuring voltage as a response to varying gas concentration or be amperometric, meaning measuring current as a response to varying gas concentration.
One key application area of ammonia sensor is in the farms and in animal facilities. To aid with simplicity, these sensors need to operate at room temperature and should have very good response time to act if the levels of ammonia go up. Fundamental study of different sensor technologies involving Chemiresitive principles (where change in resistance or conductance is measured) as well as using electrochemical principles. In the studies conducted between 2012 through 2016, the response time of these room temperature sensors ranged from 20 s to 1080 s.
It is in this context, the recent study by Praveen K Sekhar and Jesse S Kysar (An Electrochemical Ammonia Sensor on Paper Substrate , Journal of The Electrochemical Society, 164 (4) B113-B117 (2017)) at Washington State University is very interesting. They reported a paper based ammonia sensor with inkjet printed Room Temperature Ionic Liquid as electrolyte and inter digitated platinum micro prints as electrodes. They have been able to sense ammonia concentration in the range of 5 ppm to 25 ppm with 1 ppm resolution. The response times have been less than 10 s.
Simplicity of the device and the ability to integrate with MEMS based devices will enable these types of sensors to be used for intelligent environmental quality control.
For more details, you can access the full article which is available via Open Access at DOI: 10.1149/2.0941704jes