Biomimetic Control over Bimetallic Nanoparticle Structure and Activity via Peptide Capping Ligand Sequence

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Controlled synthesis of bimetallic nanoparticles (BNPs) is crucial for tuning catalytic properties.
• Biomimetic synthesis offers control over metal distribution in BNPs, but peptide influence requires deeper understanding.
• Interparticle and intraparticle compositional heterogeneity in BNPs impacts their performance.

Purpose of the Study:

• To investigate the effect of different peptides on the structural and compositional distribution of platinum-gold (PtAu) bimetallic nanoparticles.
• To correlate the observed metal distributions with the catalytic activity of the synthesized BNPs.
• To identify key descriptors for predicting and designing BNPs with enhanced catalytic properties.

Main Methods:

• Synthesis of PtAu bimetallic nanoparticles using two distinct peptides.
• Structural and compositional analysis via machine learning-assisted X-ray absorption spectra (XAS) refinement.
• Characterization of nanoparticle morphology and elemental distribution using Z-contrast scanning transmission electron microscopy (STEM).

Main Results:

• Two sets of PtAu BNPs were synthesized, exhibiting significant heterogeneity (Pt-rich, Au-rich, Au core/Pt shell).
• Catalytic activity differences were linked to the interparticle distribution of Pt and Au, modulated by the peptides used.
• The total amount of platinum within the nanoparticle shells was identified as a critical descriptor for catalytic activity.

Conclusions:

• Peptide choice significantly impacts the inter- and intraparticle metal distribution in PtAu BNPs.
• The platinum shell content is a key factor governing the catalytic performance of these heterogeneous BNPs.
• This study provides a framework for the rational design of peptide-templated bimetallic catalysts.