• ab initio calculations;
  • alloys;
  • NiCu;
  • poisoning;
  • sulfur;
  • thermodynamics

We investigated the effect of Cu alloying on S poisoning of a Ni surface via ab initio thermodynamics calculations. We found that the Cu segregation on the Ni surface weakened the S adsorption on the surface. In order to understand the weakening of the S adsorption, the S adsorption energy was evaluated as a function of d-band center with consideration of the weighted d-band scheme. The increase of Cu concentration on the top surface shifted the d-band center downward from the Fermi-level, and therefore decreased the S adsorption energy. The Cu segregation on the top surface played a key role for the improvement of S tolerance of the NiCu alloy surface.