Core–shell PdAu nanocluster catalysts to suppress sulfur poisoning

Abstract

Reducing sulfur poisoning is significant for maintaining the catalytic efficiency and durability of heterogeneous catalysts. We screened PdAu nanoclusters with specific Pd : Au ratios based on Monte Carlo simulations and then carried out density functional calculations to reveal how to reduce sulfur poisoning via alloying. Among various nanoclusters, the core–shell structure Pd₁₃Au₄₂ (Pd@Au) exhibits a low adsorption energy of SO₂ (−0.67 eV), comparable with O₂ (−0.45 eV) and lower than CO (−1.25 eV), thus avoiding sulfur poisoning during the CO catalytic oxidation. Fundamentally, the weak adsorption of SO₂ originates from the negative d-band center of the shell and delocalized charge distribution near the Fermi level, due to the appropriate charge transfer from the core to shell. Core–shell nanoclusters with a different core (Ni, Cu, Ag, Pt) and a Pd@Au slab model were further constructed to validate and extend the results. These findings provide insights into designing core–shell catalysts to suppress sulfur poisoning while optimizing catalytic behaviors.