Density functional study on the resistance to sulfur poisoning of Pt x (x = 0, 1, 4 and 8) modified α-Mo 2 C(0001) surfaces

The tolerance of sulfur poisoning of α-Mo C(0001) surfaces with different Pt coverages is investigated combining the density functional theory (DFT) results with thermodynamics data using the ab initio atomistic thermodynamic method. It is found that on Mo C(0001), Pt clusters tend to form two dimensional planar structures instead of aggregating. The clean Mo C(0001) surface interacts with sulfides very strongly and is susceptible to sulfur poisoning. With increasing the coverage of Pt on the Mo C surface, the interaction between sulfur and substrate is weakened. The sulfur tolerance ability increases in the order of Mo C ≈ Pt /Mo C < Pt /Mo C < Pt /Mo C, where the coverage of Pt on the Mo C plays a very effective role. The results provide theoretical guidance for designing Mo C based catalysts with high activity and high sulfur resistance.