| abstract |
Abstract CO is known to induce corrosion of Ni surfaces by the formation of Nickel-tetracarbonyl. In reforming applications gaseous CO induces corrosion of Ni surfaces and in syngas applications, it is known to deactivate catalysts by forming metal carbides. Spectroscopic and surface analysis methods show consensus on the fact that low coordination sites on Ni surfaces are more reactive as compared with flat planes. To investigate this observation quantitatively, we use two complementary approaches, one that is detailed, computationally intensive and the second that is less detailed, computationally less intensive but allowing studies at the time and length scales observed in experiments. In the first approach, quantum chemistry based density functional theory is used to study the adsorption of CO on atomically flat Ni(110) and Ni(111), as well as high Miller index Ni(210) and Ni(531) surfaces. The adsorption of CO at different sites on each Ni surface is examined to locate the preferred adsorption site on each surface. The structure and energetics obtained are compared with experiments wherever possible. In the second approach, coarse-grained Lattice Gas model of surface etching has been developed. The surface etching rates for three surfaces Ni(100), Ni(110) and Ni(111) are compared. We also investigated the nature of etching of defects on these three surfaces.
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