Nanostructuring copper thin film electrodes for CO₂ electroreduction to C₂₊ products

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical CO2 reduction (CO2RR) is crucial for carbon-neutral chemical processes.
• Copper-based catalysts with nanostructures show enhanced C2+ selectivity in CO2RR.

Purpose of the Study:

• To prepare and investigate Cu nanoneedles (NNs) for CO2RR.
• To correlate NN morphology and inner structure with C2+ product selectivity.

Main Methods:

• Fabrication of Cu NNs from sputtered Cu thin films via anodization.
• Tuning NN length and density using varying anodization potentials and KOH concentrations.
• Analysis of CO2RR performance at -1.0 V_RHE.
• Characterization using HAADF-STEM and XAFS spectroscopy.

Main Results:

• Anodization conditions (potential, electrolyte concentration) control NN length and density.
• High NN surface density correlates with superior C2+ selectivity.
• Anodized NNs initially form hydroxide NPs, reconstructing to metallic Cu NPs post-CO2RR.
• Optimized NNs show enhanced CO2RR selectivity towards C2+ products.

Conclusions:

• Nanostructuring Cu thin film electrodes significantly boosts CO2RR selectivity for C2+ products.
• The inner structure of NNs influences local CO concentration, promoting C2+ formation.
• Tailoring NN morphology and understanding their structural evolution are vital for advanced CO2 electrocatalysts.