Interaction of methane with Ni(111) and Ni(100); diffusion of carbon into nickel through the (100) surface; An aes-leed study

Abstract

The interaction of methane with Ni(100) results in the deposition of carbon in a carbidic form onto the surface. The sticking coefficient is initially 5 × 10−9 and does not depend on temperature in the range 474–563 K. This surface carbide consists of two different types with respect to their stability. A first kind may be made to diffuse into the bulk between 626–670 K, similar to experiments on Ni(110). A second kind is more tightly bound and leads to a segregation type of behaviour. Methane does not interact with Ni(111).