Phase-Dependent Electrocatalytic CO₂ Reduction on Pd₃ Bi Nanocrystals

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Alloying modifies catalyst electronic structures for improved performance.
• Intermetallic alloys offer well-defined atomic structures for structure-performance studies, but are synthetically challenging to produce as nanostructures.

Purpose of the Study:

• To synthesize intermetallic Pd3Bi nanocrystals using a facile solvothermal method.
• To investigate the phase-dependence of electrochemical CO2 reduction to formate.
• To understand the structure-performance correlation in Pd-based alloys for CO2 conversion.

Main Methods:

• Facile solvothermal synthesis of intermetallic Pd3Bi nanocrystals.
• Thermal annealing to induce phase transformation to solid solution alloy.
• Electrochemical CO2 reduction experiments in KHCO3 aqueous solution.
• Theoretical simulations to elucidate reaction mechanisms.

Main Results:

• Uniform intermetallic Pd3Bi nanocrystals were successfully prepared.
• Intermetallic Pd3Bi demonstrated high selectivity (≈100%) and stability for CO2 to formate reduction at -0.35 V vs RHE.
• The solid solution alloy exhibited limited formate selectivity (<60%).
• Theoretical simulations revealed that atomic ordering in intermetallic Pd3Bi suppresses CO poisoning and enhances *OCHO adsorption.

Conclusions:

• The crystallographic ordering in intermetallic Pd3Bi is crucial for selective and stable electrochemical CO2 reduction to formate.
• Intermetallic alloys provide a superior platform compared to solid solutions for CO2 conversion catalysis.
• This work highlights the potential of intermetallic nanostructures for targeted catalytic applications.