Two-Dimensional Conductive Ni-HAB as a Catalyst for the Electrochemical Oxygen Reduction Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing tunable catalytic systems is crucial for advanced catalyst design.
• Metal-organic frameworks (MOFs) offer tunable properties through synthesis.
• Oxygen reduction reaction (ORR) is vital for energy conversion technologies.

Purpose of the Study:

• To present a 2D conductive metal-organic framework (MOF) for ORR catalysis.
• To investigate the impact of crystallinity on MOF conductivity and catalytic performance.
• To elucidate the active sites in M-HAB catalysts using computational methods.

Main Methods:

• Synthesis of Ni-HAB MOFs with varying crystallinities.
• Electrochemical characterization of catalytic activity and stability.
• Density Functional Theory (DFT) simulations to probe reaction mechanisms.

Main Results:

• Two Ni-HAB catalysts with distinct crystallinities were synthesized.
• Crystallinity positively correlated with electrical conductivity.
• Enhanced crystallinity and conductivity led to improved ORR catalytic performance and stability.
• DFT suggested the hexaaminobenzene (HAB) linker is the active site, modulated by the metal center.

Conclusions:

• Tunable 2D MOFs show promise for ORR catalysis.
• Crystallinity is a key parameter for optimizing MOF conductivity and performance.
• The organic linker plays a critical role in the catalytic activity of M-HAB systems.