Engineering an Ordered Intermediate Phase between Disordered Phases for CO₂ Reduction to Multicarbon Products

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical CO2 reduction (CO2RR) to multicarbon (C2) products is key for carbon recycling but faces challenges in C2 selectivity due to C1 product preference and difficult C-C bond formation.
• Bimetallic alloys offer tunable catalysis, but random atomic arrangements limit control over active sites and C1/C2 selectivity.

Purpose of the Study:

• To develop a strategy for synthesizing ordered bimetallic alloys for enhanced CO2RR.
• To investigate the effect of atomic ordering on C2 product selectivity in CO2RR.

Main Methods:

• Composition-dependent phase engineering using a polymer nanofiber-mediated approach to synthesize ordered Au1Cu1 and disordered Au3Cu1, Au1Cu3 alloys.
• Electrochemical performance testing, including Faradaic efficiency measurements.
• In situ characterizations and theoretical calculations to analyze active site configurations and reaction mechanisms.

Main Results:

• Ordered Au1Cu1 alloy exhibited optimized d-band center and balanced intermediate binding, favoring C-C coupling over C1 formation.
• The Au1Cu1/CNFs catalyst achieved a peak Faradaic efficiency of 55.6% for C2 products at -0.5 V vs RHE.
• Electronic and geometric configurations of Au1Cu1 facilitate the lowest energy barrier for *CHO-*CO coupling.

Conclusions:

• Precise atomic-level control in bimetallic alloy ordering is demonstrated as a viable strategy for CO2RR.
• The ordered Au1Cu1 intermetallic alloy effectively guides CO2RR toward valuable multicarbon products, advancing carbon recycling technologies.