Atomically precise Ni clusters inducing active NiN₂ sites with uniform-large vacancies towards efficient CO₂-to-CO...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Carbon dioxide (CO2) electroreduction to carbon monoxide (CO) is a key strategy for CO2 fixation.
• Existing catalysts lack sufficient activity and selectivity (FEco) across a broad potential range.
• Precisely engineered active sites and vacancies are crucial for enhancing catalytic performance.

Purpose of the Study:

• To develop a general synthetic protocol for highly pure and active NiN2 catalysts.
• To precisely engineer uniform-large (UL) vacancies around the NiN2 active sites.
• To investigate the impact of UL vacancies on CO2 electroreduction performance.

Main Methods:

• Fabrication of NiN2 catalysts using a 'pre-deposition + pyrolysis' method with atomically precise Ni clusters (Ni_n).
• In-situ etching of the support using sulfur ligands from Ni clusters to create vacancies.
• Characterization using in-situ infrared spectroscopy and theoretical calculations.

Main Results:

• Achieved highly pure NiN2 catalysts with precisely engineered uniform-large (UL) vacancies.
• Demonstrated exceptional catalytic activity with a turnover frequency (TOF) of 350,000 h^-1.
• Obtained near-100% Faradaic efficiency for CO (FEco) over a wide potential range (1500 mV).

Conclusions:

• The engineered UL vacancy in highly pure NiN2 sites significantly enhances CO2 electroreduction activity and selectivity.
• The general synthetic strategy allows simultaneous engineering of active sites and vacancies using atomically precise metal clusters.
• This approach holds promise for improving catalytic performance in various chemical reactions.