In a recent study published in Engineering, researchers conducted an in-depth analysis of various sensing materials and mechanisms for detecting greenhouse gas (GHG) emissions. With the increasing concerns about global warming due to the rise of GHGs like methane (CH₄), nitrous oxide (N₂O), and carbon dioxide (CO₂), accurate quantification of these gases is crucial for sustainable agricultural practices and environmental management.
The study reviewed 95 different research works and focused on evaluating the performance of sensing materials based on parameters such as sensitivity, response ratio, response time, and recovery time. For CH₄ sensors, palladium-tin dioxide nanoparticles (Pd-SnO₂) emerged as a top performer. It demonstrated excellent response time (3 s), recovery time (5 s), sensitivity (83%), and response ratio (17.6). This is attributed to factors like high specific surface area, catalytic activity of Pd, and enhanced gas adsorption capabilities. In contrast, materials like SnO₂ nanorods-nanoporous graphene, despite having a relatively high specific surface area, showed lower sensitivity due to the absence of such effective catalytic effects.
In the case of N₂O sensors, tungsten trioxide (WO₃) nanowires with a diameter ranging from 0.5 to 15 nm stood out. They exhibited a response time of 10 s, recovery time of 60 s, and an impressive sensitivity of 2690% to 100 ppm. Their high surface-to-volume ratio, unique morphology, and stability against humidity and temperature contributed to their superior performance.
For CO₂ sensors, barium titanate (BaTiO₃)-CuO-Ag nanocomposite structures and 400 nm nanofilms showed the best results with a response time of 3 s, recovery time of 5 s, and sensitivity of 27%. The large surface area, catalytic properties, and synergistic effects of the components in this nanocomposite were key factors.
The research also compared different sensing mechanisms. Resistance measurement sensors showed moderate to high sensitivity, while field effect transistor and surface acoustic wave sensors had some limitations in sensitivity range. Electrochemical sensors were highly sensitive but required regular maintenance. Gas chromatography was accurate but expensive and time-consuming. Optical sensors faced issues like signal degradation.
Environmental factors such as temperature and humidity were found to impact sensor performance. Generally, an increase in temperature enhanced the reactivity of sensing materials but high humidity could increase response and recovery times. Strategies like regular calibration, temperature and humidity compensation, and proper sensor placement were suggested to optimize performance.
Overall, this study provides valuable insights for the development of more efficient GHG sensors. By focusing on advanced materials like Pd-SnO₂ nanoparticles, WO₃ nanowires, and BaTiO₃-CuO-Ag nanocomposites, and optimizing sensor design and calibration processes, researchers can potentially improve the accuracy and efficiency of GHG detection, thereby contributing to better environmental monitoring and sustainable agricultural practices.

The paper “An Analytical Comparison of the Performance of Various Sensing Materials and Mechanisms for Efficient Detection Capability of Greenhouse Gas Emissions,” authored by Mostafa Rastgou, Yong He, Qianjing Jiang. Full text of the open access paper: https://doi.org/10.1016/j.eng.2024.11.008. For more information about the Engineering, follow us on X (https://twitter.com/EngineeringJrnl) & like us on Facebook (https://www.facebook.com/EngineeringJrnl).