Decoding Hydrogen Spillover: Unraveling the Dual-Site Relay-Guided C-C Coupling Mechanism in CO₂ Electroreduction

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science
• Renewable Energy

Background:

• Electrochemical CO2 reduction (eCO2RR) is key for CO2 utilization and renewable energy storage.
• Aqueous eCO2RR faces challenges in activating both CO2 and H2O.
• Enhancing C2+ product selectivity is crucial for efficient CO2 conversion.

Purpose of the Study:

• To develop efficient bimetallic catalysts for aqueous eCO2RR.
• To boost C2+ product selectivity by focusing on water activation and hydrogen species (*H) generation.
• To understand the catalytic mechanism through experimental and computational studies.

Main Methods:

• Synthesis of bimetallic Cu-based catalysts with varying Co loadings.
• Electrochemical performance testing, including Faradaic efficiency (FE) and current density measurements.
• Density Functional Theory (DFT) calculations to elucidate reaction mechanisms.

Main Results:

• Optimized 0.24% Co-Cu2O catalyst achieved 76.1% FE for C2+ products at 400 mA cm-2.
• Catalyst demonstrated robust stability, maintaining >70% FE_C2+ for over 24 hours.
• Co sites facilitate water activation, generating *H that spills over to Cu sites, promoting C2+ formation.

Conclusions:

• Site-segregation strategy using bimetallic catalysts effectively enhances eCO2RR performance.
• Co-Cu2O catalyst offers a promising pathway for selective and stable CO2-to-C2+ conversion.
• This approach advances sustainable CO2 utilization and renewable energy storage solutions.