M.Phil / MS
Permanent URI for this collectionhttps://repository.cuilahore.edu.pk/handle/123456789/30
This collection archives the complete set of theses produced by students of the COMSATS University Islamabad, Lahore Campus.
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Item Enhanced Hydrogen Storage and Dissociation on Metal Doped g-C3N4 via Electric Field Modulation: A DFT Study(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Syed Muhammad Zareef; CIIT/SP24-R06-023/LHR; Prof. Dr. Mazhar Amjad Gilani; LHR TP 10027Hydrogen is a clean and sustainable energy source, yet its efficient storage and activation is still a challenge for sustainable energy solutions. This research provides theoretical study of late 3d transition metals (TM=Fe, Co, Ni, Cu, Zn) doped graphitic carbon nitride (TM@g-C3N4) systems using density functional theory with focus on adsorption and activation of hydrogen molecule. NBO charge analysis gives effective charge transfer between the transition metal centers and the g-C3N4 sheet. Frontier molecular orbital analysis and HOMO–LUMO gap provide enhanced electronic reactivity for all TM doped systems, while Co@g-C3N4 showing balance between reactivity and stability. Among all, Co@g-C3N4 has higher hydrogen adsorption with adsorption energy of -0.59 eV. The gravimetric hydrogen storage capacity of Co@g-C3N4 is up to 8.55 wt%, making it a suitable hydrogen storage material. Furthermore, the application of an external electric field modulated adsorption behavior, where positive fields increased adsorption energy, while negative fields decreased adsorption energy. Overall, this work establishes Co@g-C3N4 as an efficient single-atom catalyst and hydrogen storage material.Item Enhanced Hydrogen Dissociation on Bi-metallic Half-Sandwiched Complex: A DFT study(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Amna Zafar; CIIT/SP24-R06-002/LHR; Dr .Sara Riaz LHR TP 10014Hydrogen dissociation is an important reaction in the development of clean and sustainable energy technologies, and catalysts capable of reacting with molecular hydrogen effectively are needed to overcome the rising level of environmental pollution and traditional energy sources depletion. Clean and renewable energy sources, including hydrogen, are the potential solutions to these issues that receive more and more attention. This work has employed the simulations of the density functional theory to examine the adsorption and dissociation characteristics of hydrogen on 𝜂6-C6H6 bimetallic half-sandwiched complexes. The thermodynamic stability of all the complexes is confirmed by the calculated interaction energies, and results in negative interactions between the metals and the ligands and between the metals. Interaction energy of maximum value (-3.98 eV) occurred in FeCr(η⁶-C6H6). Electronic structure calculations of frontier molecular orbitals (FMO) and natural bond orbital (NBO) simulations show that there is a significant redistribution of charge across the bimetallic structure with profound effects of metal-metal cooperation on catalytic activity. Interaction region indicator (IRI) studies elucidated the nature of bonding contacts by showing that there were shared or partially covalent bonds in the catalytic systems.. Hydrogen adsorption and dissociation pathways is studied for all optimized complexes. Among all optimized complexes, FeMn(η⁶-C₆H₆) has an extraordinarily low activation barrier (0.18 eV), indicating greater catalytic efficiency for hydrogen dissociation. The increased activity is governed by effective charge transfer from the bimetallic centers to the antibonding orbitals of hydrogen, resulting in considerable H–H bond weakening. The pivotal insights gained from this study enhance our understanding about the stability, electronic properties and hydrogen dissociation reaction of bimetallic half sandwiched complexes.