DFT Variants for Mixed-Metal Oxides. Benchmarks Using Multi-Center Cluster Models

Area of Science:

• Computational Chemistry
• Materials Science
• Catalysis

Background:

• Mixed-metal oxides (e.g., V-Mo, Bi-Mo) are effective selective oxidation catalysts.
• Accurately modeling their complex electronic structures with DFT is challenging.
• Understanding electron localization and reaction energies is crucial for catalyst design.

Purpose of the Study:

• To assess the performance of eight DFT functionals in describing mixed-metal oxides.
• To identify functionals that accurately predict electron localization and reaction energies.
• To guide the selection of appropriate computational methods for these catalytic materials.

Main Methods:

• Evaluated eight DFT functionals: MN15, M06, PBE0-D3, B3LYP-D3, TPSSh-D3, M06-L-D3, ωB97XD, and PBE-D3.
• Tested functionals' ability to reproduce electron distributions and reaction energies against CCSD(T) benchmarks.
• Analyzed electron localization using the pseudo-Jahn-Teller effect.

Main Results:

• Hybrid functionals with ≥20% exact exchange (B3LYP-D3, MN15, PBE0-D3) showed superior performance.
• B3LYP-D3 achieved the lowest mean absolute deviation (21 kJ mol⁻¹) and accurate electron distributions.
• Other functionals exhibited trade-offs between accuracy in electron distribution and reaction energy prediction.

Conclusions:

• Hybrid DFT functionals with substantial exact exchange are recommended for modeling mixed-metal oxide catalysts.
• B3LYP-D3 demonstrates excellent accuracy for both electronic structure and reaction energetics in this context.
• Careful functional selection is vital for reliable DFT predictions in selective oxidation catalysis.