Revealing the Interface-Driven Atomic Local Chemical Heterogeneity in Bimetallic Catalysts in Three Dimensions

Area of Science:

• Materials Science
• Surface Chemistry
• Catalysis

Background:

• Subsurface atomic configurations critically influence surface electronic structures and electrocatalysis.
• Understanding 3D surface/subsurface catalyst structures is challenging due to weak interfacial signals and complex local variations.

Purpose of the Study:

• To investigate the role of local chemical heterogeneity and interfacial diffusion in Pd@Pt core-shell catalysts.
• To elucidate how subsurface structures modulate electronic properties and catalytic activity in electrocatalytic ethanol oxidation.

Main Methods:

• Atomic-resolution electron tomography was used to determine atomic structures in Pd@Pt model catalysts.
• Density functional theory (DFT) calculations were employed to understand electronic structure modifications and adsorption energies.

Main Results:

• Atomically interfacial diffusion at core-shell interfaces creates local chemical heterogeneity.
• This diffusion modulates electronic structures by shifting the d-band center, enhancing OH adsorption at Pt sites and decreasing CO adsorption at Pd sites.
• Catalytic behavior in the electrocatalytic ethanol oxidation reaction was tuned by these electronic modifications.

Conclusions:

• Local chemical heterogeneity driven by interfacial diffusion is crucial for tuning catalyst electronic structures and performance.
• The findings expand the understanding of surface-subsurface atomic interplay in catalysts.
• This research provides valuable insights for designing efficient catalysts for electrocatalysis.