Single atom catalysts on the Cr₂NO₂ MXene for CO oxidation

Area of Science:

• Materials Science
• Catalysis
• Computational Chemistry

Background:

• MXenes are a class of 2D materials with potential catalytic applications.
• Single atom catalysts (SACs) offer high efficiency and selectivity in chemical reactions.
• CO oxidation is a critical process in environmental remediation and industrial catalysis.

Purpose of the Study:

• To investigate the catalytic activity of transition metal (Sc, V, Ti) SACs on Cr2NO2 for CO oxidation.
• To evaluate the dynamic and thermal stability of the proposed catalytic systems.
• To elucidate the reaction mechanism and identify the most effective catalyst.

Main Methods:

• Density Functional Theory (DFT) calculations were employed to study adsorption and reaction pathways.
• Phonon calculations were used to assess dynamic stability.
• Ab initio molecular dynamics simulations determined thermal stability.
• The Eley-Rideal mechanism was considered for CO oxidation.

Main Results:

• Oxygen adsorption on Sc, Ti, and V resulted in partial or full dissociation.
• All transition metals facilitated the first CO oxidation step.
• Vanadium (V) sites were poisoned during the second CO oxidation due to CO2 instability.
• Scandium (Sc) and Titanium (Ti) sites allowed for feasible CO2 formation.
• Sc exhibited the lowest activation energies for CO oxidation.

Conclusions:

• Sc-decorated Cr2NO2 (Sc SACs) demonstrate enhanced catalytic performance for CO oxidation.
• The study identifies Sc SACs on Cr2NO2 as promising catalysts for CO oxidation reactions.
• Computational insights guide the development of efficient MXene-based catalysts.