Surface-Reconstructed CdNNi₃ Antiperovskite Electrocatalyst: Unlocking Ampere-Level Current Density for Hydrogen...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Ohmic loss in catalyst layers hinders large-current-density hydrogen evolution reaction (HER) efficiency.
• Development of highly conductive electrocatalysts is critical for overcoming this limitation.

Purpose of the Study:

• To screen and evaluate a highly conductive antiperovskite material, CdNNi3, as an efficient electrocatalyst for HER.
• To investigate the performance and stability of CdNNi3 at ampere-scale current densities.
• To explore the surface reconstruction phenomena during alkaline HER.

Main Methods:

• Computational screening of antiperovskite materials.
• Electrochemical characterization of CdNNi3 for HER.
• Fabrication and testing of anion-exchange membrane water electrolyzers.
• Theoretical analysis using density functional theory (DFT).

Main Results:

• CdNNi3 demonstrated high conductivity and negligible ohmic loss, functioning as an active and durable HER electrocatalyst.
• Achieved an overpotential of 235 mV at 1 A cm-2 with sustained performance over 400 hours.
• CdNNi3-based electrolyzer showed a 160 mV lower cell voltage than Pt/C at 1 A cm-2.
• Discovered dynamic surface reconstruction of antiperovskite nitrides, with Cd optimizing active sites for enhanced HER.

Conclusions:

• Antiperovskite CdNNi3 is a promising electrocatalyst for large-current-density HER, significantly reducing ohmic losses.
• The material's performance is attributed to its conductivity and dynamic surface reconstruction, which facilitates water dissociation.
• CdNNi3 offers a viable alternative to noble metal catalysts for efficient hydrogen production.