State-of-the-art of methane sensing materials: A review and perspectives

Methane (CH4) is primarily used as a fuel for heating and electricity generation throughout the world. Despite its advantages such as high calorific value and low toxicity after combustion, CH4 is considered a greenhouse gas with a global warming potential greater than CO2 per molecule. CH4 is also explosive for concentrations above the lower explosive limit. Therefore, the development of high performing, low cost and ubiquitously deployable CH4 sensing materials could be beneficial from both environmental and safety perspectives. This article reviews sensing platforms and sensing mechanisms of current CH4 sensing materials, as well as summarizing their strengths and weaknesses. Metal Oxide, Carbon Materials, Conducting Polymers, Supramolecular Materials and Metal-Organic Frameworks based on Chemi-resistive, Optical and Electroacoustic platforms are discussed. Their operating conditions, sensing performances and limit of detection are carefully reviewed. Additionally, current challenges, including water vapor cross-sensitivity and selectivity, along with future perspectives are discussed.