Ligand-Mediated Hydrogenic Defects in Two-Dimensional Electrically Conductive Metal-Organic Frameworks

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Physics

Background:

• High-surface-area materials, particularly metal-organic frameworks (MOFs), offer advantages in electrocatalysis and energy storage.
• Conductive MOFs, such as Ni3(HITP)2 and Ni3(HIB)2, are promising but their bulk metallicity requires experimental validation.

Purpose of the Study:

• To investigate the thermodynamics of hydrogen defects in conductive MOFs.
• To determine the impact of these defects on the bulk electronic properties of Ni3(HITP)2 and Ni3(HIB)2.

Main Methods:

• Thermodynamic analysis of hydrogen vacancies and interstitials.
• Computational modeling to predict defect prevalence and electronic structure.

Main Results:

• Interstitial hydrogen is identified as a plausible and prevalent defect in conductive MOFs.
• The presence of interstitial hydrogen is predicted to render Ni3(HITP)2 and Ni3(HIB)2 as bulk semiconductors, not metals.

Conclusions:

• Hydrogenic defects significantly influence the bulk properties of conductive MOFs.
• The findings challenge the metallic nature of certain conductive MOFs, suggesting semiconductor behavior due to hydrogen defects.