Activating C-C Coupling on Copper during CO₂RR: Charge-Controlled Design of Alloy Catalysts

Area of Science:

• Electrochemistry
• Materials Science
• Computational Chemistry

Background:

• Carbon dioxide (CO2) electroreduction to multicarbon (C2+) products is crucial for sustainable chemistry.
• Copper (Cu) based catalysts show unique activity for CO dimerization, a key C2+ formation step.
• Alloying Cu is a promising strategy to enhance CO2 electroreduction, but mechanisms remain unclear.

Purpose of the Study:

• To systematically investigate CO dimerization on dilute CuM(100) alloys using computational methods.
• To understand the role of p-block metal alloying in improving CO2 electroreduction activity and selectivity.
• To identify a practical descriptor for predicting catalyst performance.

Main Methods:

• Machine-learning screening of dilute CuM(100) alloys.
• Constant-potential density functional theory (DFT) simulations.
• Analysis of reaction energetics, activation barriers, and surface charge.

Main Results:

• p-block metals, especially Al and Ga, significantly lower activation barriers and increase exothermicity for CO dimerization compared to pure Cu.
• Aluminum (Al) demonstrated the highest catalytic activity among the investigated alloys.
• Electron donation from heteroatoms stabilizes the CO dimer intermediate, facilitating C-C coupling.
• A strong linear correlation was found between reaction energy and excess surface charge at a fixed potential.

Conclusions:

• Excess surface charge serves as a robust descriptor for CO2 electroreduction reaction (CO2RR) activity, integrating covalent and electrostatic effects.
• This descriptor can guide the rational design of advanced electrocatalysts for efficient C-C coupling.
• Alloying Cu with specific p-block elements offers a viable pathway to enhance CO2RR performance.