Hexagonal Close-Packed 2H-Cu Nanocrystals

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Controlling the morphology and structure of copper (Cu) nanomaterials is crucial for optimizing their properties and applications.
• Synthesizing Cu nanomaterials with unconventional phases, beyond the stable face-centered cubic (fcc) phase, presents a significant challenge.

Purpose of the Study:

• To develop a one-pot wet-chemical synthesis method for producing Cu nanocrystals (NCs) with a hexagonal close-packed (hcp, 2H type) phase.
• To investigate the catalytic performance of these 2H-Cu NCs in the electrochemical carbon dioxide reduction reaction (CO2RR) compared to conventional fcc-Cu NCs.

Main Methods:

• One-pot wet-chemical synthesis of Cu NCs.
• Electrochemical characterization of CO2RR performance, including Faradaic efficiency (FE) measurements.
• In situ characterization techniques and density functional theory (DFT) calculations.

Main Results:

• Successfully synthesized Cu NCs with the unconventional 2H-Cu phase.
• 2H-Cu NCs demonstrated enhanced catalytic activity and selectivity for CO2RR, achieving 73.1% FE for multicarbon (C2+) products at 600 mA cm-2.
• In situ studies and DFT calculations indicated that 2H-Cu NCs optimize *CO intermediate adsorption, lowering the energy barrier for C2+ formation.

Conclusions:

• Phase engineering of nanomaterials (PEN) is an effective strategy to enhance the CO2RR performance of Cu NCs.
• The 2H-Cu phase offers improved catalytic properties for CO2 conversion to valuable products.
• This work opens new avenues for exploring the potential of unconventional-phase nanomaterials.