Amperometric Gas Sensors: From Classical Industrial Health and Safety to Environmental Awareness and Public Health

Abstract

KWJ Engineering and SPEC Sensors LLC have been working to develop and commercialize a new class of amperometric gas sensor, the screen-printed electrochemical sensor (SPEC), for the past several years. These new, tiny, ultralow power sensors and device built around them are making in-roads in a diverse set of endeavors. Much of this potential has arisen in the explosion of interest and activity in sensor technologies driven by our increasingly connected world (e.g., Internet of Things). The advent of tiny form factors like the SPEC sensor has opened up new possibilities in applications requiring portability, wearability and self-powered or long-term unattended and mobile battery operation. This paper will review several recent results in next-generation gas sensor development and environmental applications at KWJ Engineering, with a focus on air quality monitoring.

High Volume Zero Power Low Cost PPB Level Printed Nano-Sensors for IoT

“…Nitrogen Dioxide Measurements with the Low Power Sensor Several gases, including CO, O3 and NO2 have been characterized using the new ultralow power printed amperometric sensor. CO and O3 having been discussed previously (7)(8)(9)(10)(11)13). Here we focus on NO2 (Figure 2).…”

“…All measurements were made at room temperature (23 -27 o C) and ambient relative humidity (50-60 %), unless otherwise specified. Two different types of test fixtures were used, one for testing sensors at the sheet level (before dicing) and another for testing diced sensors which were mounted on low power digital electronics boards, as described previously (13). NO2 was delivered from a cylinder (50 ppm air) with dynamic dilution with air to the final desired concentration.…”

Challenges and Opportunities for Printed Electrical Gas Sensors

“…Commercially, SPEC Sensors offers printed electrochemical sensors for air quality monitoring. Their sensors appear to exhibit reasonable sensitivity to O 3 (LOD = 0.028 ppm, calculated as 3× the standard deviation of the baseline), CO (<0.250 ppm, from raw data) and NO 2 (0.012 ppm (calculated) and 0.100 ppm (measured)). , The long-term stability (over 8 h), however, is ±0.150 ppm (for O 3 ) which lies above the calculated LOD. This low stability, and the fact that no tests on the influence of changing levels of RH are available, neither from the datasheet nor from publications, makes it hard to estimate the usefulness of these sensors under real-world use cases.…”

An Electrochemical Amperometric Ethylene Sensor with Solid Polymer Electrolyte Based on Ionic Liquid

“…Ionic liquids (ILs) represent promising media for the next generation of amperometric gas sensors [39][40][41] due to their unique properties such as non-flammability, sufficiently high conductivity, a large electrochemical window, structural modifiability, and excellent thermal stability. It is believed that the negligible volatility of ionic liquids can substantially improve sensor life time; in addition, their electrochemical stability allows the use of a wide range of working electrode potentials for the detection of various target gases.…”