 Abstract 2D metal organic frameworks were used as fillers in mixed matrix membranes, MMMs. These fillers have an aspect ratio of more than 30 and can be incorporated into the 4-4-foot hexafluoroasopilidine diphthalic anhydride-2-4-diamyne mesodiline-6FDA-DAM polymer matrix. This allows for better CO2 slash CH4 separation and long-term stability. This article was authored by Lei Wang, Sinyin Bai, Yao Weigu, and others.