Synthesis and characterisation of cerium based nanocomposites

Wilson, Bradley (2022) Synthesis and characterisation of cerium based nanocomposites. PhD thesis, University of Glasgow.

Abstract

This thesis presents the novel, solution based, single step methodology of reactive infiltration (RI) as a way of synthesising cerium based nanoparticles (CeNP) inside metal organic framework (MOF) structures. Through the complementary precursor-host pairing, the highly basic CeN''3 precursor reacts spontaneous within the protic MOF808 host structure, yielding the composite: CeNP@MOF808. The CeNP@MOF808 was fully characterised using a number of spectroscopic techniques, demonstrating that the structural integrity of the MOF808 host remains unchanged following the RI process, specifically the crystalline arrange and high surface area of MOF808 are retained. A combination of XAS, XPS and EELS spectroscopies demonstrated that the CeNP@MOF808 composite consists of both Ce3+ and Ce4+ oxidation states, in a 3:1 respectively, with a surface Ce ions all existing in the 3+ state.

Post-synthetic modifications, thermal and oxidative, of CeNP@MOF808 are presented, along with spectroscopic characterisation of the physio-electronic properties of the modified composites. A notable link between the microstructure of the composite and electronic Ce3+:Ce4+ structure is observed whereby thermal and oxidative post-synthetic modifications that resulted in the loss of MOF808 crystalline arrangement exhibited a concurrent reduction in the Ce3+ proportions.

Given the redox active nature of the Ce3+:Ce4+ couple, the CeNP@MOF808 composite was screened as a possible catalyst for the decomposition of the nerve agent simulant dimethyl p-nitrophenylphosphate (DMNP). Through an standard optimised methodology it was demonstrated that the CeNP@MOF808 composite exhibited improve catalytic activity towards the hydrolysis of DMNP, relative to the control MOF808 host structure.

The synthesis and characterisation of lanthanide β-ketoiminate complexes Y{OC(Me)CHC(Me)Ni Pr}3 (1) and Ce2{OC(Me)CHC(Me)Ni Pr}6 (2) was reported. Compound 2 is investigated as a possible broad spectrum precursor in the synthesis of CeO2 based nanomaterials through thermal decomposition and RI with MOF808.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: Q Science > QD Chemistry
• Colleges/Schools: College of Science and Engineering > School of Chemistry
• Supervisor's Name: Farnaby, Dr. Joy
• Date of Award: 2022
• Depositing User: Theses Team
• Unique ID: glathesis:2022-83318
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 21 Dec 2022 15:13
• Last Modified: 21 Dec 2022 15:17
• Thesis DOI: 10.5525/gla.thesis.83318
• URI: https://theses.gla.ac.uk/id/eprint/83318