Breaking the Equilibrium Yield Limit of Methane Aromatization Using Tandem Chemical Looping Catalysis

Abstract The direct conversion of methane to aromatics offers a promising route for liquefying natural gas and biogas, thereby generating higher-value chemicals and reducing transportation costs. However, conventional methane dehydroaromatization (MDA) is severely hindered by thermodynamic limitations, high temperature requirements, and catalyst instability. Here, we report a tandem chemical looping catalysis strategy that integrates chemical looping oxidative coupling of methane (CL-OCM) with dehydroaromatization (DHA), overcoming these challenges. The CL-OCM route generates more readily convertible C2+ intermediates while consuming hydrogen, the equilibrium-limiting byproduct, as water. This shifts the equilibrium and renders the overall reaction exothermic, achieving a single-pass aromatic yield of 27.1%, 2.5 to 3 times the single-pass yields of conventional MDA. Independent regeneration of the two catalyst beds maintains stable performance over repeated reaction-regeneration cycles. Process analysis projects ~75% lower levelized costs and ~77% lower cradle-to-gate emissions than direct MDA.