Engineering Multivalent Copper Catalysts From Cu-MOF Towards High-Performance C₂ Electrosynthesis

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalytic CO₂ reduction reaction (ECO₂RR) is vital for converting CO₂ into valuable chemicals.
• Achieving high selectivity for C₂₊ products in ECO₂RR remains a significant challenge.
• Cu-based catalysts with multivalent Cu are promising but require precise tuning and stabilization of active species.

Purpose of the Study:

• To develop an efficient Cu-based catalyst for selective ECO₂RR to C₂ chemicals.
• To stabilize multivalent Cu species for enhanced catalyst performance and longevity.
• To identify key intermediates and reaction pathways in the CO₂ reduction process.

Main Methods:

• Synthesis of a novel Cu-based catalyst (Cu-MOF/Cu_xO/CF-40) incorporating Cu-MOF and Cu_xO species on a Cu foil.
• Electrochemical evaluation of the catalyst's performance in ECO₂RR, including Faradaic efficiency and current density.
• In situ ATR-FTIR spectroscopy and Density Functional Theory (DFT) calculations to elucidate reaction mechanisms and identify intermediates.

Main Results:

• The Cu-MOF/Cu_xO/CF-40 catalyst achieved a total C₂ Faradaic efficiency (FE_C2) of up to 91.8% and a current density of 34.6 mA·cm^-2 at -1.1 V.
• The catalyst effectively utilizes multivalent Cu species (Cu₂₊₁O and CuO) for CO₂ adsorption, activation, and improved conductivity.
• Cu-MOF component plays a crucial role in stabilizing multivalent Cu and ensuring long-term catalyst performance.
• In situ studies and DFT calculations identified *OCCOH as the key C-C coupling intermediate.

Conclusions:

• The developed Cu-MOF/Cu_xO/CF-40 catalyst demonstrates high efficiency and selectivity for CO₂-to-C₂ conversion.
• Stabilization of multivalent Cu species via Cu-MOF is a viable strategy for enhancing ECO₂RR performance.
• This work provides a rational design approach for engineering stable and selective Cu-based electrocatalysts for CO₂ utilization.