Unveiling hydrogen-source-dominated CO₂ electroreduction activity on nitrogen-doped carbon nanotubes

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalytic CO2 reduction (eCO2RR) is crucial for CO2 utilization.
• Water (H2O) dissociation is a challenge for hydrogen sourcing in eCO2RR.
• Existing catalysts face high dissociation barriers and carbonate formation.

Purpose of the Study:

• To design novel nitrogen-doped carbon nanotubes (N-CNTs) for enhanced eCO2RR.
• To investigate the hydrogen source mechanism in eCO2RR using N-CNTs.
• To improve the activity and efficiency of eCO2RR.

Main Methods:

• Synthesis of nitrogen-doped carbon nanotubes (N-CNTs).
• Electrochemical characterization of N-CNTs for eCO2RR.
• In situ characterization and theoretical calculations to confirm reaction mechanisms.

Main Results:

• N-CNTs effectively switch the hydrogen source from H2O to hydrated protons.
• Proton-coupled electron transfer is boosted, lowering the eCO2RR barrier.
• N-CNTs achieve high Faradaic efficiency for CO (FE_CO) over a wide current density range.

Conclusions:

• The hydrogen source pathway is a critical parameter for tuning eCO2RR activity.
• N-CNTs offer a new avenue for designing efficient electrocatalysts for eCO2RR.
• This work provides insights into optimizing proton-coupled electron transfer in eCO2RR.