Engineering stable electrocatalysts by synergistic stabilization between carbide cores and Pt shells

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Core-shell nanoparticles with earth-abundant cores offer a promising strategy to enhance catalyst performance and reduce reliance on expensive noble metals.
• However, the structural and catalytic stability of these materials is often compromised under harsh reaction conditions, such as those in the oxygen reduction reaction (ORR).

Purpose of the Study:

• To investigate the stabilization effect of atomically thin platinum (Pt) shells on titanium tungsten carbide (TiWC) cores.
• To evaluate the durability and structural integrity of these core-shell nanoparticles under electrochemical stress relevant to the ORR.

Main Methods:

• In situ, time-resolved experiments to observe core protection mechanisms.
• Advanced microscopy techniques to study nanoparticle dynamics during potential cycling.
• Accelerated electrochemical ageing studies involving over 10,000 potential cycles.

Main Results:

• Atomically thin Pt shells effectively stabilized TiWC cores against oxidation and dissolution, even at high potentials.
• Complete Pt coverage maintained the core-shell structure and atomic composition throughout extensive electrochemical cycling.
• Partially and fully coated nanoparticles exhibited distinct structural dynamics under potential cycling.

Conclusions:

• Atomically thin Pt shells provide exceptional protection for earth-abundant transition metal carbide (TMC) and nitride (TMN) cores.
• The demonstrated durability of fully coated core-shell nanoparticles highlights their potential for advanced catalytic applications.
• This core-shell architecture offers a viable route to develop robust and cost-effective catalysts.