Catalysis plays a crucial role in everyday life and industrial processes, and computational chemistry provides powerful tools to uncover the atomistic details of catalytic reactions that experiments alone cannot fully reveal.
This thesis applied state-of-the-art computational methods to address key challenges in catalysis. In the first part, we investigated reactions of alcohols and alkenes in H-ZSM-5 zeolites using a hybrid QM:QM approach. We demonstrated that methods beyond GGA functionals—particularly B3LYP+D2—accurately predict infrared spectra and describe the potential energy surface correctly, whereas the commonly used PBE+D2 functional yields inaccurate results. We developed a QM:QM-DOS-P approach incorporating anharmonic effects to enable chemically accurate predictions of adsorption free energies at the hybrid DFT level. We also implemented an enhanced sampling scheme interfaced with the QM:QM setup to analyze reaction pathways, thereby obtaining, for the first time, free energies corrected at the hybrid-functional level for the ethyloxonium and tert-butyl carbenium ions.
In parallel, we investigated benzothiazole formation in bulk water using Path-metadynamics. We revealed that water reduces reaction barriers through hydrogen-bond networks via a Grothuss mechanism, enabling sustainable synthesis under mild, green conditions.
Overall, this thesis underscores the importance of methodological developments that balance accuracy and efficiency in computational catalysis.
Dipanshu Kumar was born on June 30, 1998, in Begusarai, Bihar, India. He completed his high school education in 2015 and subsequently joined the National Institute of Science Education and Research (NISER), Bhubaneswar, India, to pursue a 5-year Integrated MSc degree. For his master’s thesis, Dipanshu conducted a two-year research internship under the supervision of Dr. Upakarasamy Lourderaj at NISER, Bhubaneswar. His research focused on energy transfer in formaldehyde-graphene collisions. In 2021, Dipanshu obtained his Integrated MSc with a major in Chemistry and a minor in Physics.
Since October 2021, he has been a PhD candidate at the Department of Theoretical and Computational Chemistry of Radboud University, under the supervision of Prof. dr. Herma Cuppen and Dr. Daria Galimberti. His PhD research focuses on advancing methods for computational catalysis, particularly for reactions in zeolites using hybrid QM:QM methods and enhanced sampling techniques and has resulted in several publications.