Highly selective CO₂ electroreduction in an exsolution-induced flow cell using a hierarchical monolithic nano-Ag foam...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical CO2 reduction is key for carbon neutrality, but faces challenges like salt precipitation and electrode flooding in conventional cells.
• Existing silver catalysts on carbon cloth in flow-through induced dynamic triple-phase boundary (FTDT) cells have limited active sites and poor stability.

Purpose of the Study:

• To develop a novel electrode material for enhanced electrochemical CO2 reduction in FTDT cells.
• To improve the performance and stability of catalysts for CO2 electrolysis.

Main Methods:

• Fabrication of a monolithic nano-silver foam electrode with hierarchical nanostructures and well-developed pores.
• Characterization of the electrode's electrochemically active surface area (ECSA) and structural properties.
• Electrochemical testing in an FTDT cell at industrial current densities.

Main Results:

• The nano-Ag foam electrode exhibits an ECSA ten times greater than conventional Ag nanoparticles (Ag NPs) electrodes.
• The nanostructure accelerates bubble nucleation, and the pore design provides abundant dynamic triple-phase boundaries (TPBs).
• Achieved 93% CO faradaic efficiency and 51.34% overall energy efficiency at 200 mA cm-2 and 2.34 V.

Conclusions:

• The monolithic nano-Ag foam electrode significantly enhances CO2 electroreduction performance in FTDT cells.
• The improved electrode design addresses limitations of previous catalysts, offering a viable path for commercial CO2 electrolysis.
• This work presents a promising strategy for efficient and stable electrochemical CO2 conversion towards carbon neutrality.