An in situ exsolved Cu-based electrocatalyst from an intermetallic Cu₅Si compound for efficient CH₄ electrosynthesis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts for CO2 reduction reaction (CO2RR) is crucial for carbon utilization.
• Copper-based materials are promising for CO2RR but often face challenges with selectivity and stability.

Purpose of the Study:

• To develop a high-performance electrocatalyst for CO2RR.
• To enhance methane selectivity and overall activity in CO2 reduction.

Main Methods:

• Synthesis of an in situ exsolved ultrathin SiO2 layer-coated CuO/Cu nanoparticle catalyst (e-Cu5Si) on a Cu5Si substrate.
• Electrochemical evaluation of the catalyst for CO2RR in a flow cell.
• In situ Raman spectroscopy for mechanistic investigation.

Main Results:

• The e-Cu5Si catalyst achieved a methane Faradaic efficiency (FE) of 49.0% and a partial current density over 140.1 mA cm-2 at -1.2 V vs RHE.
• The catalyst demonstrated outstanding stability during the CO2 reduction reaction.
• In situ Raman analysis revealed the role of the SiO2 layer in stabilizing active Cu+ species and promoting key reaction intermediates.

Conclusions:

• The strongly coupled multiphase interfaces in e-Cu5Si facilitate efficient interfacial electron transfer for CO2RR.
• The ultrathin SiO2 layer is key to stabilizing active sites and enhancing the protonation pathway for methane formation.
• This work presents a promising strategy for designing advanced electrocatalysts for selective CO2 conversion to valuable products like methane.