(753b) Structure Sensitivity of Dimethyl Ether Electro-Oxidation

Dimethyl Ether (DME) is an attractive chemical for both on-board hydrogen generation as well as a fuel in direct electro-oxidation in fuel cells.^{[1, 2]}  Experimental studies of the electro-oxidation have demonstrated significant structure sensitivity on Pt – specifically when comparing the (111) and (100) facets.^[3]   Using periodic, self-consistent density functional theory calculations, we evaluate the thermodynamics of dimethyl ether (DME) electro-oxidation on a number of model (100) and (111) facets of monometallic fcc catalysts, including Au, Ag, Cu, Pt, Pd, Ni, Ir, Rh.  Using the results, we predict the most-probable reaction mechanism on each of these catalysts.  Based on these proposed mechanisms, we predict the energy efficiency and catalytic activity of each of these metals.  Furthermore, by comparing results on the (111) and (100) facets, we attempt to elucidate the origins of the experimentally observed structure sensitivity of DME electro-oxidation.

[1] Semelsberger, T. A.; Borup, R. L.; Greene, H. L., Journal of Power Sources 2006, 156, 497-511.

[2] Kerangueven, G.; Coutanceau, C.; Sibert, E.; Leger, J. M.; Lamy, C., Journal of Power Sources 2006, 157, 318.

[3] Lu, L.; Yin, G.; Tong, Y.; Zhang, Y.; Gao, Y.; Osawa, M.; Ye, S., Journal of Electroanalytical Chemistry 2010, 642, 82.