(185c) Surface Poisoning of RuO2(110) by Formation of Carbonate

Base metal oxides have long been of interest as catalysts for oxidation of small molecules such as CO, NO, or SO2, but practical applications are limited by surface poisoning.[1] With growing interest in the role of metal oxide films in the oxidation activity of even the more noble metals, it is important to understand and ultimately to learn to bypass surface poisoning. RuO2 has been widely studied and characterized as a CO oxidation catalyst, and experimental observations suggest that this activity can be poisoned under some conditions by the formation of a surface carbonate.[2] In this work, we use plane-wave, supercell DFT calculations to explore the formation of carbonate on an RuO2(110) surface and determine its implications for surface poisoning. We show that several carbonate forms are possible. In general, carbonate adsorbs weakly and, based on equilibrium calculations, competes ineffectively with oxygen adsorption. The more favorable kinetics of carbonate formation are likely important to the observed high carbonate coverages [3] at high O2 pressures.

[1]: K. Kolasinski, Surface Science: Foundations of Catalysis and Nanoscience, Wiley, (2002).

[2]: A. Lafosse, Y. Wang, and K. Jacobi, J. Chem. Phys., 117, 2823 (2002).

[3]: M. Rossler, S. Giinther, and J. Wintterlin, J. Phys. Chem. C, 111, 2242 (2007).