Pulsed Electrolysis with a Nickel Molecular Catalyst Improves Selectivity for Carbon Dioxide Reduction

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Pulsed electrolysis shows promise for improving carbon dioxide reduction on metal electrodes.
• The impact of short voltage steps on molecular electrocatalysts remains largely unexplored.
• Understanding these effects is crucial for developing efficient electrocatalytic systems.

Purpose of the Study:

• To investigate the effect of pulsed electrolysis on the selectivity and stability of a homogeneous electrocatalyst, [Ni(cyclam)]²⁺.
• To determine how tuning potential and pulse duration influences the electrocatalytic performance.
• To explore the potential for pulsed electrolysis in controlling molecular electrocatalyst activity.

Main Methods:

• Utilized pulsed electrolysis with varying potential and pulse durations.
• Employed a homogeneous electrocatalyst, [Ni(cyclam)]²⁺, on a carbon electrode.
• Monitored CO Faradaic efficiencies and catalyst stability over time.

Main Results:

• Achieved significant improvement in CO Faradaic efficiencies, reaching 85% after 3 hours.
• Observed double the efficiency compared to potentiostatic conditions.
• Identified in situ catalyst regeneration from an intermediate as the key factor for improved activity.

Conclusions:

• Pulsed electrolysis can significantly enhance the selectivity and stability of molecular electrocatalysts.
• Tuning potential and pulse duration offers a method to control electrocatalytic performance.
• This approach presents a promising strategy for optimizing carbon dioxide reduction.