Ultrathin palladium nanosheets with selectively controlled surface facets

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Developing ultrathin 2D nanomaterials with controlled surface facets is crucial for advanced catalytic applications.
• Palladium nanocrystals are widely studied for catalysis, but precise control over exposed facets remains a challenge.

Purpose of the Study:

• To develop a facile bottom-up synthetic approach for preparing ultrathin 2D palladium nanosheets (PdNSs) with selectively exposed surface facets.
• To investigate the facet-dependent catalytic performance of these PdNSs for hydrogen evolution reactions (HERs).

Main Methods:

• Utilized nanoconfined lamellar mesophases of amphiphilic functional surfactants as templates for PdNS growth in aqueous solution.
• Employed preferential adsorption of functional groups and halide ions onto specific Pd planes to control epitaxial growth of desired surface facets ({100}, {110}, {111}).
• Evaluated the electrocatalytic activity and stability of the synthesized PdNSs for HERs.

Main Results:

• Successfully synthesized ultrathin 2D palladium nanosheets with selectively exposed {100}, {110}, and {111} surface facets.
• Demonstrated that {100}-exposed PdNSs exhibit superior catalytic activity and stability for HERs compared to {110}, {111}-exposed PdNSs, and bulk palladium.
• The synthetic approach is general, scalable, and allows precise control over surface facets.

Conclusions:

• The surfactant-templated synthesis provides a powerful and scalable method for fabricating 2D palladium nanosheets with tailored surface facets.
• Facet engineering is critical for optimizing the catalytic performance of palladium nanocrystals, as evidenced by the enhanced HER activity of {100}-exposed PdNSs.
• The findings offer a guideline for designing surfactant templates for other 2D metal nanosheets with controlled surface facets.