In a recent study published in Engineering, researchers analyzed various sensing materials and mechanisms for detecting greenhouse gas (GHG) emissions. With growing concerns about global warming caused by rising levels of GHGs like methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2), accurate measurement of these gases is becoming crucial for sustainable farming and environmental management.
SnO2: tin dioxide; ZnO: zinc oxide; WO3: tungsten trioxide; In2O3: indium oxide; Pt: platinum; Pd: palladium; Ag: silver; PANI: polyaniline; PT: polythiophene; PPy: polypyrrole; SWCNTs: single-walled carbon nanotubes; MWCNTs: multi-walled carbon nanotubes. Image Credit: Mostafa Rastgou et al.
The study looked at 95 different research papers, focusing on how well sensing materials performed based on sensitivity, response ratio, response time, and recovery time.
For CH4 sensors, palladium-tin dioxide nanoparticles (Pd-SnO2) stood out as the top choice. They performed exceptionally well with a fast response time (3 seconds), quick recovery time (5 seconds), high sensitivity (83 %), and a response ratio of 17.6. These results are thanks to their large surface area, the catalytic properties of palladium, and their ability to adsorb gas effectively.
On the other hand, materials like SnO2 nanorods paired with nanoporous graphene didn’t perform as well, even though they had a high surface area. The lack of strong catalytic effects was the key limitation.
For N2O sensors, tungsten trioxide (WO3) nanowires—ranging in diameter from 0.5 to 15 nanometers—came out on top. They delivered a response time of 10 seconds, a recovery time of 60 seconds, and an impressive sensitivity of 2690 % to 100 ppm. Their standout performance was due to their high surface-to-volume ratio, unique structure, and stability under varying humidity and temperature conditions.
When it came to CO2 sensors, the best results came from barium titanate (BaTiO3)-CuO-Ag nanocomposites and 400 nm nanofilms. These materials showed a quick response time (3 seconds), recovery time (5 seconds), and a sensitivity of 27 %. Their success is largely due to the combination of materials, which increased surface area and provided strong catalytic properties.
The researchers also compared different sensing mechanisms. Resistance-based sensors were found to have moderate to high sensitivity, while field effect transistor and surface acoustic wave sensors had limitations in their sensitivity range. Electrochemical sensors performed well in terms of sensitivity but required frequent maintenance. Gas chromatography stood out for its accuracy but was expensive and time-consuming. Meanwhile, optical sensors were effective but faced issues like signal degradation over time.
Environmental factors like temperature and humidity also played a significant role in sensor performance. Higher temperatures often improved the reactivity of sensing materials, but high humidity could slow down response and recovery times.
To address these challenges, the researchers suggested strategies like regular calibration, compensating for temperature and humidity variations, and carefully choosing where sensors are placed.
Overall, the study provides important insights for designing better GHG sensors. By focusing on advanced materials like Pd-SnO2 nanoparticles, WO3 nanowires, and BaTiO3-CuO-Ag nanocomposites—and improving calibration and sensor designs—researchers could help make GHG detection more accurate and efficient. This would support better environmental monitoring and help promote sustainable agricultural practices.
Journal Reference:
Rastgou, M., et. al. (2025) An Analytical Comparison of the Performance of Various Sensing Materials and Mechanisms for Efficient Detection Capability of Greenhouse Gas Emissions. Engineering. doi.org/10.1016/j.eng.2024.11.008