(356f) Bridging the Gap in Catalysis Research: A Multifaceted DFT-Kmc-Lstm Approach to Investigate Heterogeneous Catalytic Reactions

A comprehensive understanding of complex heterogeneous catalytic reactions is crucial for the development of innovative catalysts for industrial and environmental applications. Due to the intricate nature of reaction mechanisms and the multitude of parameters involved, such as geometric, electronic, thermodynamic, and kinetic properties, it is challenging to easily understand and accurately predict catalytic performance. Density Functional Theory (DFT)^[1] and Kinetic Monte Carlo (kMC)^[2] simulations are two commonly used approaches for examining catalytic reactions at atomic and microscopic levels, respectively. However, neither method alone can provide complete information on the precise reaction mechanisms and the effect of various parameters on catalytic activity.

In this study, we employed a combined DFT and kMC approach to holistically assess diverse catalytic properties, with each method complementing the other^[3-5]. DFT simulations were utilized to delve deeper into the mechanistic aspects of the catalytic reaction, examining thermodynamic factors such as reaction potentials and activation barriers, as well as electronic characteristics like charge states and orbital distribution of catalyst materials. Nonetheless, DFT alone has limitations in explicitly capturing the spatiotemporal evolution of active site distributions and concentrations of adsorbates, which are essential for a comprehensive evaluation of catalyst materials. This is because DFT simulations typically considering only a small portion of the reaction system and not accounting for the influence of the surrounding environment on reaction kinetics. To address these limitations, we integrated the obtained DFT parameters, such as reaction-free energy and activation energy barrier, into a high-fidelity surface reaction kMC model. This allowed us to trace the spatiotemporal evolution of surface-level kinetics, including adsorbate localization, surface coverage changes, reaction turnover frequency (TOF), We considered realistic environmental factors, such as temperature, pressure, and the influence of the surrounding environment on active sites.

As a case study, we applied this multifaceted approach to investigate the electrochemical nitrogen reduction reaction (NRR) on various non-precious-based transition metal oxide (TMO) surfaces, considered an alternative to the Haber-Bosch process for ammonia synthesis. Our results revealed several TMO catalysts with exceptional NRR performance, particularly V₂O₃, which demonstrated the lowest overpotential value (0.38 V) and highest reaction rates with a calculated reaction TOF of 1.010^-5 s^-1 under mild conditions (300K and 1bar). This finding is particularly significant, as the calculated TOF value is 1000 times greater than that of a noble Ru electrocatalyst, considered the benchmark. Overall, our work highlights the importance of a multidisciplinary approach for understanding complex catalytic reactions and designing novel catalysts for practical applications.

References

[1] Weijing, D., Weihong, Z., Xiaodong, Z., Baofeng, Z., Lei, C., Laizhi, S., ... and Ge, S. The application of DFT in catalysis and adsorption reaction system. Energy Procedia, 2018, 152, 997-1002.

[2] Prats, H., Illas, F., and Sayós, R. General concepts, assumptions, drawbacks, and misuses in kinetic M onte C arlo and microkinetic modeling simulations applied to computational heterogeneous catalysis. International Journal of Quantum Chemistry, 2018, 118(9), e25518.

[3] Lee, C. H.; Pahari, S.; Sitapure, N.; Barteau, M. A.; Kwon, J. S. I., DFT-kMC Analysis for Identifying Novel Bimetallic Electrocatalysts for Enhanced NRR Performance by Suppressing HER at Ambient Conditions Via Active-Site Separation. Acs Catal 2022, 12(24), 15609-15617

[4] Sitapure, N.; Epps, R.; Abolhasani, M.; Kwon, J. S. I., Multiscale modeling and optimal operation of millifluidic synthesis of perovskite quantum dots: Towards size-controlled continuous manufacturing. Chem Eng J, 2021, 413.

[5] Sitapure, N.; Qiao, T.; Son, D. H.; Kwon, J. S. I., Kinetic Monte Carlo modeling of the equilibrium-based size control of CsPbBr3 perovskite quantum dots in strongly confined regime. Comput Chem Eng 2020, 139