Defect-driven MXenes for enhanced electrocatalytic nitrogen reduction: a first-principles and microkinetic study

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrocatalytic nitrogen reduction reaction (ENRR) is a sustainable route for ammonia synthesis.
• Current challenges include low N2 activation efficiency and undefined catalyst structure-activity relationships.

Purpose of the Study:

• To systematically investigate vacancy-engineered M2CT2 MXenes for ENRR.
• To establish a quantitative structure-activity relationship for rational catalyst design.

Main Methods:

• Density functional theory (DFT) calculations.
• Microkinetic modeling.
• Free energy calculations.

Main Results:

• Surface vacancies enhance N2 adsorption and activation by modulating MXene electronic structure.
• The ENRR proceeds via the distal pathway on VT-M2CT2.
• A new descriptor, Psi, correlates structure with activity, enabling catalyst screening.
• Vacancy-engineered Ti2CBr2 demonstrates superior ENRR performance.

Conclusions:

• Defect-mediated MXene catalysts offer a universal design strategy.
• This work facilitates the development of efficient ENRR electrocatalysts.