Efficient Bifunctional Electrocatalysts for Oxygen Evolution/Reduction Reactions in Two-Dimensional Metal-Organic...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Bifunctional catalysts for oxygen reduction (ORR) and oxygen evolution (OER) are essential for advanced energy technologies like metal-air batteries and fuel cells.
• Developing highly active, stable, and conductive catalysts is a key challenge in this field.

Purpose of the Study:

• To investigate the ORR and OER performance of two-dimensional (2D) metal-organic frameworks (MOFs) of the TM3(HADQ)2 type.
• To understand the electronic structure-activity relationship governing the catalytic performance.

Main Methods:

• Computational screening of TM3(HADQ)2 materials for ORR/OER activity.
• Analysis of electronic structure using d-band center (εd) and crystal orbital Hamilton populations (COHP).
• Validation of catalytic properties and acidity using constant potential method (CPM) and microkinetics.

Main Results:

• Rh3(HADQ)2 demonstrated promising bifunctional ORR/OER activity with a low overpotential of 0.31 V for both reactions.
• The catalytic activity is primarily influenced by the d-electron number of the central metal atom, ligand electronegativity, and intermediate oxygen atom.
• Rh3(HADQ)2 was identified as an acidic bifunctional catalyst with high toxicity tolerance.

Conclusions:

• Rh3(HADQ)2 is a potential cost-effective, bifunctional oxygen-electric catalyst with high activity and stability.
• This research provides insights for the rational design of single-atom catalysts (SACs) for various catalytic applications.
• The findings contribute to the development of efficient catalysts for energy conversion devices.