Functional Catalytic Surfaces for Environmental Sustainability

Abstract

Functional surfaces are of crucial importance to both fundamental and applied science. Many phenomena are driven by the properties of interfaces: catalysis, corrosion and adhesion to name a few. These properties can be modified using surface functionalisation, which in this thesis is applied to three areas of environmental concern: sustainable catalytic carbon-carbon coupling, atmospheric CO2 sequestration and photocatalytic water purification. Chapter 1 provides an introduction to these three areas and Chapter 2 summarises the common experimental techniques used throughout this thesis.
Chapters 3 and 4 describe the application of pulsed plasma deposition for production of palladium functionalised catalysts for common carbon-carbon coupling reactions. For low loading palladium catalyst cloths in Chapter 3, high product yields and selectivities have been measured in conjunction with environmentally friendly solvents. In Chapter 4, palladium - poly(ionic liquid) catalyst membranes are described, which demonstrate selective permeation (separation) of the product species through the underlying membrane support. Both low loading palladium catalyst cloths and palladium - poly(ionic liquid) catalyst membranes display low levels of metal leaching allowing them to be recycled multiple times.
Chapter 5 extends the use of pulsed plasma deposited imidazole moieties to the directed liquid-phase epitaxial (layer-by-layer) growth of metal-organic frameworks (MOFs). The MOF-508 functionalised surface displays CO2 gas capture behaviour at atmospheric concentrations proportional to the number of MOF-508 layers.
Finally, Chapters 6 and 7 describe the preparation of separable P25 TiO2 based photocatalysts. Micron-sized silica-steel microcomposite core with TiO2 nanocomposite shell photocatalysts were prepared using sol-gel chemistry in Chapter 6. Their application to degradation of waterborne organic pollutants during UV illumination has been demonstrated, along with recycling via magnetic separation. Chapter 7 describes photocatalytic P25-TiO2 composite macrospheres, which possess both UV and visible light photocatalytic activity depending on the synthesis conditions. These macrospheres have been demonstrated for their use in flat bed reactors under visible light irradiation, for application to point of use solar driven removal of water borne contaminants. Additionally, Appendix 1 outlines work carried out on the fundamentals of P25 TiO2 photocatalysts, using XRD and photocatalytic degradation studies.