(759b) Fundamental Insights into Electrochemical Oxidation of Methane over Transition Metals | AIChE

(759b) Fundamental Insights into Electrochemical Oxidation of Methane over Transition Metals

Authors 

Prajapati, A. - Presenter, University of Illinois at Chicago
Singh, M., University of Illinois At Chicago
Collins, B., University of Minnesota Twin Cities
Goodpaster, J., University of Minnesota Twin Cities
Natural gas has not only remained one of the major sources of energy, but also a valuable feedstock for various petrochemicals, plastics, and pharmaceuticals. The primary component of natural gas is methane which is approximately 23 times more potent greenhouse gas than CO2 and contributes significantly to global warming. Oxidation of methane can be potentially helpful in reducing the environmental impact of methane. Current industrially relevant processes recently developed technologies like direct methane solid oxide fuel cells are extremely energy intensive and therefore, there is a need to find a sustainable route to oxidize methane. In the present work, we show a systematic study on ambient electrochemical oxidation of methane. To synthesize low-overpotential, highly efficient electrocatalysts, it is important to study the interaction between the catalytic sites and methane and a preferred reaction pathway on the catalyst for methane oxidation. We perform Density Functional Theory (DFT) calculations to determine the binding energies and free energy changes between intermediates for methane oxidation. These calculations are used to gain mechanistic insight and the relationships between the catalyst composition and catalytic activity. We also propose a novel method to experimentally estimate the catalyst-CH4 binding energy trends for the transition metal catalysts. The electrochemical study is done in a compact methane-sparged stagnant-electrode well-mixed-electrolyte H-cell in a near neutral environment. The transition metals are used as the working electrodes and Pt as the counter. The catalysts are characterized by SEM, EDS, and XPS both pre and post-electrochemical reaction. The methane oxidation products are determined by GC and HPLC and the product distribution, partial current densities, and Faradaic efficiencies over catalysts is also shown as a part of this work.