(735z) Unraveling Dynamic Surface Restructuring and Intricate Reaction Networks in Catalysis Via Integrated DFT-Microkinetic Modeling

Computational catalysis has emerged as a powerful tool for rational catalyst design, particularly in heterogeneous catalysis, offering cost-effective and predictive capabilities. However, accurately modeling realistic and dynamic catalytic conditions encountered in practical systems remains a challenge. Conventional computational techniques often struggle to capture the surface restructuring induced by temperature, pressure, and gas compositions, as well as the intricate reaction network complexity. To address these limitations, we have developed an integrated approach combining density functional theory (DFT) and microkinetic simulations to study catalytic processes under realistic conditions, with a focus on complex reaction networks.

In this talk, I first illustrate the surface restructuring of Cu-based single-atom alloy (SAA) catalysts under reaction conditions. Our findings reveal the thermodynamic instability of RhCu-SAA and NiCu-SAA structures upon acetylene adsorption, leading to the aggregation of Rh and Ni atoms on the surfaces. Conversely, the PdCu-SAA and PtCu-SAA surfaces favor the selective hydrogenation of acetylene to ethylene, consistent with experimental observations. Additionally, we probed the surface aggregation of PtCu-SAA during butadiene hydrogenation reactions, where butadiene adsorption induces the aggregation of surface Pt atoms. Microkinetic analysis successfully explained the experimental butene isomer product distribution, a feat that DFT calculations alone could not achieve.

The second topic focuses on the selective catalytic oxidation of NH₃ (SCO-NH₃) on Ag catalysts. While Ag exhibits good reactivity and N₂ selectivity, the mechanisms, detailed kinetics, and the relationship between surface structure and reactivity/selectivity under oxidizing environments remain unclear. Our studies on Ag(111) and Ag(211) surfaces revealed the preference for either O-assisted or OH-assisted oxidation pathways, depending on the intermediates and reaction temperatures. Microkinetic results predicted the formation of O-covered Ag surfaces under realistic SCO-NH3 conditions on pure Ag catalysts. We systematically investigated SCO-NH₃ mechanisms on surface-oxidized Ag catalysts. Notably, these oxidized Ag surfaces exhibited intermediate activity compared to Ag(111) and Ag(211), along with strong oxygen storage abilities and reactivity from both adsorbed surface oxygen and lattice oxygen species. These insights highlight the importance of considering Ag catalyst oxidation during SCO-NH₃ and facilitate the design of novel SCO-NH₃ catalysts.

Overall, the integration of DFT and kinetic calculations accelerates catalyst design and provides molecular-level understanding of reactions and catalyst structural evolutions under various conditions, offering a powerful approach to unravel dynamic surface restructuring and intricate reaction networks in catalysis.

References

K. Yang, B. Yang, Identification of reaction mechanisms and role of surface oxygen in selective catalytic oxidation of ammonia over surface-oxidized Ag surface: A DFT and microkinetic study, In preparation

K. Yang, B. Yang, Identifying the reaction network complexity and structure sensitivity of selective catalytic oxidation of ammonia over Ag surfaces. Applied Surface Science 2022, 584, 152584, doi.org/10.1016/j.apsusc.2022.152584

K. Yang, B. Yang, Identification of the Active and Selective Sites over a Single Pt Atom-Alloyed Cu Catalyst for the Hydrogenation of 1,3-Butadiene: A Combined DFT and Microkinetic Modeling Study. Journal of Physical Chemistry C 2018, 122 (20), 10883-10891, doi.org/10.1021/acs.jpcc.8b01980

K. Yang, B. Yang, Surface Restructuring of Cu-based Single-atom Alloy Catalysts under Reaction Conditions: The Essential Role of Adsorbates. Physical Chemistry Chemical Physics 2017, 19 (27), 18010-18017, doi.org/10.1039/C7CP02152F