Understanding the effect of steps, strain, poisons, and alloying: Methane activation on Ni surfaces

It is shown that a single parameter characterizing the electronic structure of a transition metal surface, the d-band center (epsilon(d)), can be used to provide a unified description of a range of phenomena in heterogeneous catalysis. Using methane activation on Ni surfaces as an example, we show that variations in epsilon(d) can be used to quantitatively describe variations in the activation energy when the surface structure is changed, when the coverage of carbon is changed, when the surface is strained, when the surface is alloyed, and when the surface is poisoned by sulfur. The d-band center is, therefore, a very general descriptor of the reactivity of a surface.