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

Pulsed electrolysiscan significantly improve carbondioxide reductionon metal electrodes, but the effect of short (millisecond to seconds)voltage steps on molecular electrocatalysts is largely unstudied.In this work, we investigate the effect pulse electrolysis has onthe selectivity and stability of the homogeneous electrocatalyst [Ni(cyclam)](2+) at a carbon electrode. By tuning the potential and pulseduration, we achieve a significant improvement in CO Faradaic efficiencies(85%) after 3 h, double that of the system under potentiostatic conditions.The improved activity is due to in situ catalyst regeneration froman intermediate that occurs as part of the catalyst's degradationpathway. This study demonstrates the wider opportunity to apply pulsedelectrolysis to molecular electrocatalysts to control activity andimprove selectivity.

Automated summary

Pulsed electrolysis can significantly enhance CO2 reduction on metal electrodes, but its effect on molecular electrocatalysts with short voltage steps remains largely unexplored. In this study, we investigate how pulse electrolysis affects the selectivity and stability of the homogeneous electrocatalyst [Ni(cyclam)](2+) on a carbon electrode. By tuning the potential and pulse duration, we achieve a remarkable improvement in CO Faradaic efficiencies (85%) after 3 hours, doubling that of the system under potentiostatic conditions. This research demonstrates the potential of applying pulsed electrolysis to molecular electrocatalysts for controlling activity and improving selectivity.