Protective Surface Amorphization Enabling Electrocatalytic Pt Alloy Synthesis

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Developing efficient catalysts is crucial for various chemical processes.
• Ultrathin 2D nanomaterials offer high surface area but can be unstable.
• Controlling surface structure is key to enhancing catalytic performance.

Purpose of the Study:

• To develop a novel surface-specific amorphization strategy for ultrathin 2D platinum nanodendrites (2D-PtNDs).
• To engineer conformal platinum-metal (Pt-M) surface alloys with enhanced catalytic properties.
• To establish a scalable method for creating amorphous alloy skins on noble metal catalysts.

Main Methods:

• Utilizing a silica nanoshell confinement strategy to protect 2D-PtNDs during surface modification.
• Employing sodium borohydride (NaBH4) treatment to induce surface-specific amorphization.
• Investigating off-equilibrium redox exchange (antigalvanic alloying) for incorporating secondary metal ions (Pd, Ag, Au, Ru).

Main Results:

• Achieved a surface-specific amorphization, creating an amorphous Pt
• skin
• rich in high-energy sites.
• Successfully synthesized conformal Pt-M surface alloys with tunable compositions on 2D-PtNDs.
• Demonstrated significantly enhanced electrocatalytic activity for ethanol oxidation, achieving ~89% Faradaic efficiency to CO2 and an order of magnitude higher mass activity than commercial Pt/C.
• Showed that Ag alloying doubled the catalytic activity of bulk platinum substrates.

Conclusions:

• The silica nanoshell strategy enables controlled surface amorphization and alloy formation without structural collapse.
• The engineered amorphous alloy skins provide extraordinary reactivity and enhanced catalytic performance.
• This work presents a general and scalable route for creating advanced noble metal catalysts with amorphous surface alloys for improved catalysis.