The use of electrochemical fuel cells for chemical synthesis and conversion has been growing over the last several years and has significant potential for methane oxidation reactions. Methane is a potent greenhouse gas that is hard to store and transport, so converting methane to a liquid product such as methanol would allow for easy transportation while still producing a valuable chemical and fuel. Achieving a partial oxidation of methane, however, has been extremely challenging due to its molecular symmetry. We designed a novel electrochemical fuel cell that includes a gas-diffusion electrode to boost the cell’s methane conversion and an aqueous chamber to increase methane partial oxidation selectivity. We tested utilizing hydrogen peroxide, which has previously been used to oxidize methane to methanol. However, hydrogen peroxide’s high cost inhibits its economic viability when used on a large scale. Our unique fuel cell design allows for the <i>in-situ</i> production of hydrogen peroxide on the counter electrode. On the working electrode, we report the results of using iron oxide catalysts for electrocatalytic methane oxidation reactions motivated by our previous work showing the earth abundant and nontoxic iron oxide to be effective at catalyzing C—H bond cleavage for methane oxidation. In our experiments, we examined the effects of changing electrolyte alkalinity and composition, concentrations of hydrogen peroxide (as seen in the figure below), gas composition, and catalyst and support material on the methane oxidation reaction. The cell’s performance was measured using electrochemical techniques and Differential Electrochemical Mass Spectrometry (DEMS).

Utilization of an electrochemical fuel cell for the oxidation of methane

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.