Electrocatalytic Partial Oxidation of Methane to Liquid Fuels over Metal Oxide Catalysts
Abstract
Methane to high-value liquid fuel conversion is critical for enabling efficient utilization of abundant natural gas resources while overcoming challenges associated with methane storage and transportation. 1 However, the conventional industrial routes for converting methane into liquid products rely largely on indirect reforming processes that require high-temperature operation (> 800 o C), multistep processing, and substantial energy input. 2 From a molecular perspective, the high bond dissociation energy of methane (104 kcal mol -1 ) imposes severe kinetic barriers to C-H activation, while the thermodynamic preference for complete oxidation drives partially oxidized intermediates toward CO 2 formation. 3 This intrinsic coupling of kinetic difficulty and thermodynamic over-oxidation fundamentally limits the simultaneous achievement of high activity and selectivity. Consequently, electrocatalytic partial oxidation of methane has attracted increasing interest, since electrochemical systems allow precise regulation of reaction potential and oxidation pathways under mild conditions. 4 Nevertheless, selectively activating methane while suppressing over-oxidation remains a fundamental challenge for current catalytic technologies. 5 In this work, a series of MOₓ (M = Fe, Cu, Ni) catalysts is designed to regulate methane electrocatalytic oxidation through controlled metal–oxide interactions. Tailoring the intrinsic redox properties of the metal oxides modulates oxygen vacancy formation energies, lattice oxygen participation, and interfacial charge transfer, thereby decoupling methane activation from over-oxidation pathways. This study elucidates the role of metal–oxide interactions in controlling methane oxidation behavior and demonstrates enhanced activity in three-electrode electrochemical systems. Beyond intrinsic catalytic insights, the metal oxide catalysts are further integrated into membrane–electrode assemblies (MEAs) to evaluate their performance and stability under device-relevant electrochemical conditions. Reference N. F. Dummer et al., Chemical Reviews , 123 , 6359–6411 (2023). S. Yuan et al., Advanced Energy Materials , 10 , 1–19 (2020). M. R. A. Kishore, S. Lee, and J. S. Yoo, Advanced Science , 10 , 1–18 (2023). N. Xu et al., Applied Catalysis B: Environmental , 282 , 119572 (2021) . 5. K. Shen et al., Journal of the American Chemical Society , 145 , 6927–6943 (2023).