Core–shell PdAu nanocluster catalysts to suppress sulfur poisoning†
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.