Rational design of 2D MBene-based bifunctional OER/ORR dual-metal atom catalysts: a DFT study.

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Developing low-cost, highly active bifunctional catalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is critical for advancing metal-air batteries.
• Existing catalysts often rely on expensive noble metals, necessitating the exploration of alternative materials.

Purpose of the Study:

• To theoretically design and investigate novel two-dimensional (2D) MBenes doped with dual-metal atoms as efficient bifunctional OER/ORR electrocatalysts.
• To identify promising catalyst candidates and understand the descriptor relationship between electronic properties and catalytic activity.

Main Methods:

• Density functional theory (DFT) calculations were employed to systematically study a series of dual-metal atom adsorbed MBenes (2TM/TM1TM2-Mo2B2O2, TM = Mn, Fe, Co, Ni).
• Calculated overpotentials for OER and ORR were compared against benchmark catalysts like IrO2(110) and Pt(111).
• Bader charge analysis was used to establish a descriptor for catalytic activity.

Main Results:

• Several dual-metal MBenes, including 2Ni-Mo2B2O2, FeCo-Mo2B2O2, and CoNi-Mo2B2O2, demonstrated outstanding bifunctional OER/ORR catalytic activity.
• These catalysts exhibited lower overpotentials than IrO2(110) for OER and Pt(111) for ORR, and effectively suppressed the hydrogen evolution reaction (HER).
• A linear correlation was found between Bader charge of dual-metal atoms and ORR overpotential, and a volcanic correlation with OER overpotential.

Conclusions:

• The studied dual-metal MBenes represent highly efficient, noble metal-free bifunctional electrocatalysts for OER/ORR applications.
• This theoretical work provides valuable guidance for designing advanced MBenes-based electrocatalysts for energy storage technologies.
• The Bader charge serves as an effective descriptor for predicting and optimizing OER/ORR catalytic performance.