Progress and key challenges in catalytic combustion of lean methane

As a primary type of clean energy, methane is also the second most important greenhouse gas after CO₂ due to the high global warming potential. Large quantities of lean methane (0.1–1.0 vol%) are emitted into the atmosphere without any treatment during coal mine, oil, and natural gas production, thus leading to energy loss and greenhouse effect. In general, it is challenging to utilize lean methane due to its low concentration and flow instability, while catalytic combustion is a vital pathway to realize an efficient utilization of lean methane owing to the reduced emissions of polluting gases (e.g., NO_x and CO) during the reaction. In particular, to efficiently convert lean methane, it necessitates both the designs of highly active and stable heterogeneous catalysts that accelerate lean methane combustion at low temperatures and smart reactors that enable autothermal operation by optimizing heat management. In this review, we discuss the in-depth development, challenges, and prospects of catalytic lean methane combustion technology in various configurations, with particular emphasis on heat management from the point of view of material design combined with reactor configuration. The target is to describe a framework that can correlate the guiding principles among catalyst design, device innovation and system optimization, inspiring the development of groundbreaking combustion technology for the efficient utilization of lean methane.