Carbon induced segregation of Ni atoms in Cu-Ni alloy

We reported a novel driving force for surface segregation of CuNi alloy by using first-principles theoretical calculation. It is found that carbon atoms dissolved in the CuNi alloy are segregated to the surface with Ni atoms, leading to the formation of Ni-rich skin alloy, which is completely different from the previously reported Cu-rich skin alloy. Moreover, the well-known Van der Waals interaction between graphene and the CuNi surface does not reverse the segregation tendency of Cu-rich surface. Our study provides a novel approach to tune the surface composition of alloy catalyst and thus the catalytic activity of the bimetallic catalysts.