Computational studies of the initial stages in TiO2-MOF interface formation

Patabandi Mudiyanselage, Anuradha 2022. Computational studies of the initial stages in TiO2-MOF interface formation. MPhil Thesis, Cardiff University. Item availability restricted.

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Abstract

TiO2 has been significantly used in photocatalytic applications for decades as an inert and sustainable material. However, TiO2 is less efficient in the photoinduced processes due to the rapid recombination of the photogenerated electrons and holes. Therefore, TiO2-based heterogeneous composites (i.e., TiO2-MOF, TiO2-CNT) are widely investigated given the ability to increase the efficiency of photoinduced applications rather than the individual state of the interacted materials. This thesis presents a computational chemistry study on the energetics and structures of rutile and anatase TiO2 polymorphs, the interaction of terephthalic acid (TPA) and metal species with TiO2, and the interaction of metal organic framework (MOF) nodes with TiO2, aiming to investigate the TiO2/MOF heterointerface, which currently is not fully comprehended. The comparison of energetic, geometric, and electrical properties of bulk rutile and anatase polymorphs of TiO2 identified that the PBEsol exchange correlation functional with a light basis set is the most appropriate computational approach for discovering TiO2-based novel materials. The study of different surface energies, geometric and electrical properties of certain low Miller index facets of TiO2 demonstrated that a 4-layer slab model, with the top 2-layers unconstrained of (110) facet of rutile and the (101) facet of anatase are the best models to study the chemical interactions with TiO2. The study of TPA interaction with TiO2 surfaces and the interaction of Zn, Ti and Zr based metal species with the adsorbed TPA on rutile and anatase TiO2 surfaces gave evidence for the possible layer-by-layer deposition of MOFs on TiO2. The interaction study of a simplified version of MOF nodes of Zn-MOF-5, Ti-MIL-125 and Zr-UiO-66 with TiO2 surfaces proved that the deprotonated TPA linkers of MOF nodes favourably bind with the Ti ions on the TiO2 surface, giving evidence for the possible synthesis of TiO2-MOF composites using already formed MOF crystals. Generally, the interaction studies concluded that the deprotonated TPA linkers are highly compatible to bind with the TiO2 surfaces and thus, the growth of MOFs with TPA linkers on TiO2 is highly favourable. Interactions between bulk crystal structures of different MOFs and hydroxylated TiO2 surfaces can be investigated to further understand the formation and nature of the TiO2-MOF interface

Item Type:	Thesis (MPhil)
Date Type:	Completion
Status:	Unpublished
Schools:	Chemistry
Date of First Compliant Deposit:	8 June 2022
Last Modified:	04 Jan 2023 02:22
URI:	https://orca.cardiff.ac.uk/id/eprint/150282

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