Reactive Force Field Development for Propane Dehydrogenation on Platinum Surfaces.

Area of Science:

• Computational Chemistry
• Materials Science
• Chemical Engineering

Background:

• Propane dehydrogenation (PDH) is a crucial industrial process for propylene production, operating at high temperatures (773-973 K).
• Developing efficient and sustainable PDH catalysts, particularly platinum (Pt)-based ones, is an active area of research.
• Accurate atomistic simulations are essential for optimizing Pt catalysts but require robust reactive force fields.

Purpose of the Study:

• To develop a new reactive ReaxFF force field, termed 2023-Pt/C/H, for large-scale simulations of PDH reactions on Pt surfaces.
• To enable detailed investigations into the reactivity and dynamic properties of Pt-catalyzed PDH mechanisms.
• To provide a computational tool for optimizing catalyst design and understanding deactivation pathways.

Main Methods:

• Optimization of ReaxFF force field parameters using a comprehensive dataset from density functional theory (DFT) calculations.
• Training data included geometries, adsorption energies, and reaction barriers for key steps in the Pt-catalyzed PDH mechanism on Pt(111).
• Validation through internal consistency checks and application in reactive molecular dynamics (MD) simulations.

Main Results:

• The 2023-Pt/C/H force field achieved high accuracy, with mean absolute errors of 14 kJ/mol for intermediate energies and 12 kJ/mol for energy barriers against DFT.
• MD simulations successfully modeled propylene formation and competing deactivation reactions (deep dehydrogenation, C-C cleavage) on various Pt surface topologies.
• Reactivity and selectivity followed the order Pt(111) < Pt(100) < Pt(211), with stepped surfaces showing higher activity and selectivity due to low-coordinated sites.

Conclusions:

• The developed 2023-Pt/C/H reactive force field accurately captures the complex reaction network of propane dehydrogenation on Pt surfaces.
• It provides insights into the influence of surface topology and temperature on PDH activity and selectivity.
• This computational tool facilitates future research on Pt-based catalysts, including effects of surface structure, temperature, pressure, and coverage.