Ce³⁺/Ce⁴⁺ Ion Redox Shuttle Stabilized Cu^δ+ for Efficient CO₂ Electroreduction to C₂H₄

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Carbon dioxide electroreduction (CO2RR) offers clean carbon conversion but struggles with efficiency and C2 product selectivity.
• The dynamic Cuδ+ state aids C-C coupling but is unstable under harsh electrocatalytic conditions.
• Maintaining stable Cuδ+ species is crucial for improving CO2RR performance.

Purpose of the Study:

• To develop a strategy for stabilizing the Cuδ+ state during CO2RR.
• To enhance the selectivity and efficiency of multi-carbon products in CO2 electroreduction.
• To investigate the role of cerium (Ce) doping in stabilizing active copper species.

Main Methods:

• Cerium (Ce) doping of copper oxide (CuO) to create a Ce/CuO x catalyst.
• In situ infrared spectroscopy and in situ X-ray photoelectron spectroscopy to analyze catalyst behavior.
• Density functional theory (DFT) calculations to understand reaction mechanisms and energy barriers.

Main Results:

• The Ce/CuO x catalyst achieved a 60% Faradaic efficiency for multi-carbon products (C2H4, CH3CH2OH, CH3COOH).
• High selectivity for C2H4 (40%) was observed at -1.2 V vs. RHE with 25-hour stability.
• Ce doping stabilized the Cuδ+ state by forming Ce-Cu redox ion pairs, lowering the *CO coupling energy barrier.

Conclusions:

• Cerium doping effectively stabilizes the Cuδ+ active site for enhanced CO2 electroreduction.
• The Ce/CuO x catalyst demonstrates significant improvements in selectivity and stability for C2 products.
• This work presents a novel approach using lanthanide metals for advanced catalysis and clean energy applications.