Cu─O─Al Interfacial Engineering on Cu Nanowires for Durable CO₂ Electroreduction Into Multi-Carbon Products

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Achieving high selectivity and long-term stability in multi-carbon (C2+) production via CO2 electrocatalysis (eCO2RR) is challenging due to competing pathways and catalyst degradation.
• Copper-based catalysts are promising for eCO2RR but often suffer from stability issues and limited selectivity for C2+ products.

Purpose of the Study:

• To develop a core-shell heterostructure catalyst for enhanced selectivity and stability in eCO2RR.
• To investigate the role of an aluminum oxide (AlOx) shell in stabilizing copper (Cu) catalysts and promoting C2+ formation.

Main Methods:

• Synthesis of copper nanowires (Cu NWs) encapsulated with an aluminum oxide (AlOx) shell.
• Characterization using in situ Raman spectroscopy and density functional theory (DFT) calculations.
• Electrochemical performance evaluation in a flow-cell configuration, including Faradaic efficiency (FE) and stability tests.

Main Results:

• The AlOx shell stabilized Cu+ species and created a local alkaline microenvironment, optimizing intermediate coverage for C-C coupling.
• The core-shell catalyst achieved a C2+ Faradaic efficiency (FE) of 69.6% at 600 mA cm-2 and maintained FE_C2+ above 50% for 64 hours at 300 mA cm-2.
• Tuning AlOx shell crystallinity influenced product distribution by altering *OH adsorption.

Conclusions:

• AlOx encapsulation is a promising strategy to simultaneously enhance selectivity and durability of Cu-based catalysts for eCO2RR.
• The core-shell heterostructure effectively addresses the critical challenge of balancing selectivity and stability in CO2 electrocatalysis.