Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.788914
Title: Utilisation of CO2 for the preparation of inorganic solids
Author: Bennett, Matthew John
Awarding Body: University of Hull
Current Institution: University of Hull
Date of Award: 2019
Availability of Full Text:
Access from EThOS:
Access from Institution:
Abstract:
The work in this project reports: (1) the preparation of the mixed oxide carbonates; Sr₂CuO₂(CO₃), Sr₁:₈Ba₀:₂CuO₂(CO₃) and Sr₁:₇₅Ca₀:₂₅CuO₂(CO₃) via direct reaction of the parent oxides with CO₂, (2) the extraction of CO₂ to re-form the original oxides and (3) a Density Functional Theory (DFT) model for understanding the thermodynamics and structural changes of Sr₂CuO₃ reacting with CO₂, forming Sr₂CuO₂(CO₃). The one-dimensional structured series of Sr₂₋ₓAₓCuO₃ (A = Ca, Ba and x = 0 - 2) was directly reacted with CO₂, forming oxide carbonates. An alternating gaseous approach was used so CO₂ would react within the anion vacancies of these compounds at specific temperatures. Identical reaction parameters were used for barium and strontium compounds, however calcium compounds required a longer residence time. This has been attributed to the smaller anion vacancies and lower CO₂ reaction affinity. In all cases CO₂ could be removed from the oxide carbonates to re-form the original oxides for consequent reactions. The structural changes as well as carbonate formation were studied using a DFT model. This showed how atomic positioning changes when forming Sr₂CuO₂(CO₃) from the original oxide. An ∆Hᵣₓₙ value was calculated which included the enthalpy of structural rearrangement, ∆Hstructure, and formation of the carbonates, ∆Hcarbonate. This provides an insight into the thermodynamics involved when forming mixed oxide carbonates from an oxide. Ce₂MnN₃ and the Sr₂₋ₓBaₓPdO₃ (x = 0 - 2) series are both isostructural to Sr₂CuO₃ and were also investigated. Sr₂₋ₓBaₓPdO₃ compounds indicated only surface carbonates whilst Ba₂PdO₃ resulted in Ba₁₁Pd₁₁O₂₀(CO₃)₂, BaCO₃ and Pd metal. CO₂ splitting has been proposed to occur with Ce₂MnN₃, resulting in reactions with O₂ forming CeO₂ and MnO₂.
Supervisor: Francesconi, M. Grazia ; Benoit, David M. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.788914  DOI: Not available
Keywords: Chemistry
Share: