Atomically Dispersed Ni-Cu Catalysts for pH-Universal CO₂ Electroreduction.

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Carbon dioxide (CO2) electroreduction is crucial for mitigating emissions and closing the carbon cycle.
• Challenges in neutral/alkaline electrolytes include carbonate formation and low CO2 utilization.
• Acidic CO2 reduction is promising but hindered by the hydrogen evolution reaction.

Purpose of the Study:

• To design a novel catalyst for efficient and pH-universal CO2 electroreduction to CO.
• To overcome limitations of existing electrolytes for CO2 electroreduction.
• To investigate the catalytic mechanism and electronic interactions within the catalyst.

Main Methods:

• Synthesis of a Ni-Cu dual atom catalyst supported on hollow nitrogen-doped carbon.
• Electrochemical evaluation of the catalyst across acidic, neutral, and alkaline electrolytes.
• Operando characterizations and density functional theory (DFT) calculations.

Main Results:

• The Ni-Cu dual atom catalyst achieved ≈99% CO Faradaic efficiency universally.
• High partial current densities for CO were observed: 190 ± 11 (acidic), 225 ± 10 (neutral), and 489 ± 14 mA cm⁻² (alkaline).
• Acidic conditions yielded a CO2 utilization efficiency of 64.3%, double that of alkaline conditions.

Conclusions:

• The Ni-Cu dual atom catalyst demonstrates exceptional performance for pH-universal CO2 electroreduction.
• Electronic interactions between Ni and Cu atoms are key to accelerating *COOH intermediate formation.
• The study elucidates the reaction mechanism, offering insights for future catalyst design.