Adsorbate diffusion on transition metal nanoparticles.

Area of Science:

• Surface Science
• Heterogeneous Catalysis
• Computational Chemistry

Background:

• Adsorbate diffusion on transition metal nanoparticles is crucial for heterogeneous catalysis.
• Atomistic understanding of diffusion mechanisms is vital for optimizing catalytic processes.

Purpose of the Study:

• To systematically study the adsorption and diffusion of atomic and diatomic species on Pt and Cu nanoparticles.
• To investigate the influence of nanoparticle size and shape on diffusion mechanisms.
• To establish relationships between diffusion barriers and adsorbate binding energies.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Adsorption and diffusion of H, C, N, O, CO, and NO on Pt and Cu nanoparticles were simulated.
• Nanoparticle sizes and shapes were varied.

Main Results:

• Nanoparticles exhibit stronger binding of adsorbates compared to extended single crystal surfaces.
• A Brønsted-Evans-Polanyi-type linear correlation was identified between transition state and initial state energies for diffusion across nanoparticle edges.
• Adsorbate diffusion barriers on nanoparticle edges can be estimated using binding energies.

Conclusions:

• The findings offer valuable insights into diffusion-mediated chemical reactions catalyzed by transition metal nanoparticles.
• The established correlation provides a predictive tool for understanding catalytic activity.
• This research contributes to the fundamental knowledge of surface processes in heterogeneous catalysis.