There is accelerating acknowledgment that methane (CH₄) is a key contributor to the anthropogenic greenhouse effect, motivating efforts to both minimize future emissions and reduce what is already in the atmosphere [1]. While progress has been made towards understanding and monitoring methane emissions, effectively no progress has been made for CH₄ capture [2].

Unlike CO₂ which exists in relatively high atmospheric concentrations (~ 410 ppm), the deleterious effects of CH₄ are felt at much lower concentrations (~ 2 ppm) [1]. Further, CH₄ is far less reactive as both its geometry and polarity render the C–H bonds inert [3]. Therefore, we are faced with a challenge where atmospheric capture is desired, but CH₄ exists at low concentrations and is not intuitively targeted through conventional chemical adsorption mechanisms.

We argue that this lack of progress, particularly in contrast to CO₂, is because of a lack of fundamental knowledge necessary to predict and design materials that may selectively adsorb CH₄. Specifically, beyond a simple classical dipole argument [4], the scientific community does not have the requisite understanding of what makes the surface of a material interact strongly with competing species (e.g., CO₂, H₂O, N₂ and O₂) rather than with CH₄. Our goal is to advance the basic science understanding of methane itself by studying the material–methane interface and tailoring it to target methane’s valence molecular orbitals.

Success will be measured by the development of an experimentally corroborated quantitative model correlating adsorbent surface variables, such as composition, structure, and surface potential, to adsorption strength. This model will be disseminated to the community in the form of quantitative “design rules” in high-impact peer-reviewed journals.

To make CH₄ capture a reality on the necessary timescales, we must rapidly build a knowledge base using cutting-edge computational and experimental techniques. Without first laying this foundation, the community will continue to spin its wheels attempting to engineer top-down solutions and waste precious time. This proposed work, when successful, will serve as the needed scientific foundation for the targeted design and intuitive study of adsorbents with enhanced selectivity for CH₄, and ultimately allow us to determine if physical adsorption is a viable path forward for atmospheric methane capture technologies.