Location: Sustainable Water Management Research
Project Number: 6066-13000-006-031-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 2, 2024
End Date: Sep 1, 2026
Objective:
The objective of this project is to develop low-cost real-time greenhouse gas emission measurement via an electrochemical sensor array using nanoengineered components to characterize ammonia, carbon dioxide, methane, and nitrous oxide. The developed sensor array will be deployed as part of a sensing network to allow the wireless measurement of greenhouse gas emissions from agricultural row crop and poultry production. The project will design and create a library of functional nanomaterials for integration into electorchemical sensor arrays.
Approach:
Nanoengineered membranes with selective permeability will be assembled to generate unique sensor responses that allow for the characterization of ammonia, carbon dioxide, methane, and nitrous oxide levels. A library of functionally diverse materials will be evaluated for selection and integration into the electrochemical sensor arrays. These arrays will be fabricated on top of electrodes on glass or flexible substrates that allow for individually addressable responses for each gas of interest.
Fabrication of the ammonia, carbon dioxide, and methane sensors involves patterning photoresist on the substrate as a protective mold prior to the deposition of gold for the working electrode and counter electrode. The surface of the working electrode will be selectively coated with multi wall carbon nanotubes (MWCNT) or platinum nanoparticles by electrodeposition. A thin layer of silver will be selectively deposited to form the reference electrode by using the photoresist mold. The silver electrode will be uniformly chlorinated with a buffer solution to overcoat the nanoparticles. MWCNT or nanoparticles on the surfaces of the electrodes drastically increase surface area which allows for high efficiency electrochemical sensing.
Fabrication of the nitrous oxide sensor will be performed by patterning of a resistive heater and platinum electrode on glass. YSZ (Yttria stabilized zirconia) will be placed on top of the patterns and another platinum electrode will be constructed on top. The resistive heater will be heated on demand to elevate temperature in a confined space up to 700°C. Nitrous oxide gas in air will be fed into the sensor and the elevated temperatures will remove common oxygen components and leave only oxygen gas from N2O which can be amperometrically detected for diffusion of oxygen through YSZ.
The fabricated sensors will then be integrated into a wireless remote sensing network being developed as part of the parent project. The performance of the experimental sensors will be evaluated against commercial sensors when deployed in agricultural production environments.
