(617ee) Developing Catalysts for the Partial Electrochemical Oxidation of Methane

Michael J. Boyd, Chris Hahn, Thomas F. Jaramillo

Department of Chemical Engineering, Stanford University

Partial oxidation of methane to methanol and other oxygenates is an appealing alternative to methane steam reforming and Fischer-Tropsch reactions. Traditional heterogeneous catalyst systems require high temperatures to overcome the activation barriers for methane oxidation, leading to complete oxidation of methane to carbon dioxide. Electrocatalysis, however, offers precise control of catalyst-free surface energies via applied potential, and is a promising approach to high conversion and selectivity for methane partial oxidation at low temperatures. Our work investigates the activity of Pt and several other transition metal catalyst materials for low temperature electrochemical methane oxidation. The effects of mass transport are assessed via the use of multiple reactor designs, including rotating disk electrode, gas diffusion electrode, and membrane electrode assembly. Several methods of detecting products, including Nuclear Magnetic Resonance, Gas Chromatography, and Differential Electrochemical Mass Spectrometry, are employed to identify interesting active materials. Catalysts are characterized ex-situ via Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy, and X-ray Diffraction. Up till now we have observed methane adsorption on noble metal surfaces at low potentials, followed by oxidation when sweeping to higher potentials.