(583h) Ethane Electrochemical Oxidative Dehydrogenation: Impact of Electrocatalyst Tuning and Feedstock Composition

As an alternative to steam cracking of ethane to form ethylene, oxidative dehydrogenation (ODH) is a more thermodynamically favored route. Despite this thermodynamic favorability, adoption of ODH is complicated by safety and product selectivity concerns. Implementing process designs for oxidative dehydrogenation that mitigate these drawbacks is an active area of research. Previous work at Ohio University’s Institute for Sustainable Energy and the Environment (ISEE), supported by the U.S. Department of Energy’s National Energy Technology Laboratory [DE-FE0031709], has demonstrated the improved performance achieved by a solid oxide fuel cell (SOFC) design using a mixed-metal oxide electrocatalyst to perform electrochemical-ODH (e-ODH). The cathode, anode, and full reactions are presented below.

Cathode: 1/2O₂ + 2e^- → O^2-

Anode: C₂H₆ + O^2- → C₂H₄ + H₂O + 2e^-

Full: C₂H₆ + 1/2O₂ → C₂H₄ + H₂O E_{700 °C} = 0.904 V

An advantage of mixed-metal oxides is the possibility of site-specific metal cation substitution, which can tune the physical and catalytic properties of the material. Ongoing work at ISEE has explored the impact that site-specific substitution has upon the electrocatalyst performance for e-ODH.

Practical implementation of an e-ODH SOFC system requires knowledge about how feed composition will affect the reaction performance. This knowledge would be used to determine if e-ODH would require associated processing steps. To evaluate whether e-ODH would need drying operations, the impact of a humidified versus a dry ethane feedstock will be tested.

This presentation will cover the impact of site-specific metal cation substitution upon the mixed-metal oxide electrocatalysts used for e-ODH and the effects of a humidified versus a dried ethane feed. Chemical and electrochemical testing results and materials characterization will be presented.