Pressure-Induced Forward-Shift of Proton-Coupled Electron Transfer Step Boosts CO-to-Acetate Throughput

Area of Science:

• Catalysis Science
• Electrocatalysis
• Surface Chemistry

Background:

• The rate-determining step (RDS) is crucial for catalysis efficiency and selectivity.
• CO/CO2 electroreduction is limited by voltage-insensitive *CO-*CO dimerization, hindering multi-carbon production.
• Conventional catalyst modifications often negatively impact downstream reactions.

Purpose of the Study:

• To develop a physical microenvironment engineering strategy for CO electroreduction.
• To reconfigure reaction pathways by modulating pressure.
• To overcome the limitations of *CO-*CO dimerization in multi-carbon production.

Main Methods:

• Physical microenvironment engineering via pressure modulation.
• Utilizing a synthetic Copper-Palladium single-atom alloy (Cu-Pd SAA) catalyst.
• High-pressure operando Raman spectroscopy to analyze reaction intermediates and pathways.

Main Results:

• Elevated CO pressure redirects proton reaction pathways, favoring *CO hydrogenation over dimerization.
• Reduced Tafel slope observed for acetate and hydrogenated intermediates.
• Achieved 85% Faradaic efficiency for CO-to-acetate conversion with 33% energy efficiency and 700h stability.
• Maintained >75% acetate selectivity across a wide current density range (3-1500 mA cm⁻²).

Conclusions:

• Pressure modulation is an effective strategy to engineer microenvironments and control electrocatalytic pathways.
• The Cu-Pd SAA catalyst system demonstrates high selectivity, efficiency, and stability for CO-to-acetate conversion.
• The system's broad current density compatibility suggests potential for integration with intermittent renewable power sources.