Lateral CO diffusion on micropatterned Ag/CuO arrays enables efficient CO₂-to-C₂₊ electroreduction.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalytic CO2 reduction to multi-carbon (C2+) products is industrially significant.
• Tandem Cu-based catalysts improve C2+ selectivity but face limitations from spatial configurations.
• Optimizing intermediate CO transport is key for efficient C2+ production.

Purpose of the Study:

• To investigate the impact of catalyst spatial configuration on CO2 reduction to C2+ products.
• To decouple CO generation and consumption through tunable Ag/CuO array structures.
• To establish a design strategy for spatially structured tandem catalysts.

Main Methods:

• Fabrication of layer-stacked and array-patterned Ag/CuO catalysts with varying array spacings (200, 400, 800 μm).
• Electrochemical evaluation of catalysts for CO2 reduction reaction (CO2RR) performance.
• Operando infrared microscopy to visualize *CO coverage and diffusion dynamics.

Main Results:

• Array-patterned Ag/CuO catalysts outperformed layer-stacked designs, highlighting the importance of lateral CO diffusion.
• Optimal C2+ selectivity was achieved with a 400 μm array spacing (Ag-CuO-400), yielding 63% ethylene faradaic efficiency at 300 mA cm-2.
• Operando studies revealed an effective lateral *CO diffusion length of ~200 μm, indicating an optimal balance for C-C coupling.

Conclusions:

• Anisotropic *CO transport significantly influences C2+ selectivity in electrocatalytic CO2 reduction.
• Spatially structured tandem catalysts with optimized array spacing offer a promising strategy for enhanced C2+ production.
• Precise control over intermediate diffusion pathways is crucial for designing high-performance electrocatalysts.