Porous gas diffusion electrodes (GDEs) were prepared using; (i) solubilised polymer binders and Au coated porous polymer substrates (ii) sintered PTFE or PVDF binders and porous carbon substrates. Type (i) GDEs were capable of catalysing H<SUB>2</SUB> oxidation at significant rates but rates of CH<SUB>3</SUB>OH oxidation were <I>ca</I>. 100 times lower. They also suffered from ohmic limitations, poor long term stability and poor reproductibility between similar electrodes. Type (ii) GDEs showed much improved rates of CH<SUB>3</SUB>OH oxidation compared with Type (i) but were highly dependant on PTFE concentration and only marginally affected by the catalyst loading. The rate of H<SUB>2</SUB> and CH<SUB>3</SUB>OH oxidation on Type (i) GDEs appeared independent of the catalyst used (Pd or Pt/Ru) while CH<SUB>3</SUB>OH oxidation on Type (ii) GDEs altered according to the Pt/Ru ratio. Various base materials ((Ni/C), Ni<SUB>3</SUB>C, (W, Fe<SUB>6</SUB>W<SUB>6</SUB>C), (W, Co<SUB>6</SUB>W<SUB>6</SUB>C)) were prepared as Type (ii) electrodes but were found to corrode rapidly in H<SUB>2</SUB>SO<SUB>4</SUB> making them unsuitable as electrocatalysts. Newly synthesised materials, (Ni/W/C), (Ni/Mo/C) and (Ni/W/Mo/C) were also prepared as Type (ii) GDEs. (Ni/Mo/C) and (Ni/W/Mo/C) were passive in hot H<SUB>2</SUB>SO<SUB>4</SUB> at <0.25V<SUB>(SCE)</SUB> respectively; beyond this they corroded transpassively which was attributed to the poor corrosion resistance of Mo<SUB>2</SUB>C under acidic conditions. Both materials showed some activity for H<SUB>2</SUB> oxidation but (Ni/Mo/C) showed no activity for CH<SUB>3</SUB>OH oxidation while (Ni/W/Mo/C) showed a low rate of oxidation in the passive region. (Ni/W/C) was passive throughout the potential range examined and showed electrocatalytic activity for H<SUB>2</SUB> and CH<SUB>3</SUB>OH oxidation; CH<SUB>3</SUB>OH oxidation occurred at over potentials significantly lower than observed on noble metal catalysed electrodes. The WC component of (Ni/W/C) was thought to passivate the Ni component rendering it catalytically active. Electrodes prepared using Pt/WC and Pt/Ru/WC showed inferior electrocatalytic activity for the oxidation of CH<SUB>3</SUB>OH than Pt/Ru of a comparable loading. In addition higher rates of corrosion were observed compared with plain WC.

This work reports the effect of oxygen doping on the anisotropic electrical resistivity and thermoelectric power of single crystal YBa₂Cu₃O_x and nominally 6%Ca-doped YBa₂Cu₃O_x. The a, b and c-axis thermopower of single crystal YBa₂Cu₃O_xhas been measured over a wide doping range. The overdoped a-axis thermopower of single crystal YBa₂Cu₃O_xand nominally 6%Ca doped YBCO displays an unusual abrupt change in gradient at about 130K, which is independent of doping. This effect becomes more noticeable as the doping is increased. However it is not observed in any underdoped a-axis thermopower measurements. The a-axis thermopower an be scaled in terms of <i>T</i>*, in a similar way to polycrystalline YBCO. However the overdoped a-axis thermopower will not scale because of the abrupt gradient change and the negative value of the overdoped a-axis thermopower. At high dopings the b-axis single crystal thermopower of YBa₂Cu₃O_xshows markedly different behaviour to the a-axis thermopower, both in magnitude and temperature dependence. This is ascribed to a significant additional contribution from the chain conduction channel. However as the doping is progressively lowered the b-axis thermopower becomes more similar to the a-axis thermopower, reflecting the decreasing effect of the chain contribution on the b-axis thermopower. This can be observed in the in-plane thermopower anisotropy <i>S_a</i>(<i>T</i>)/<i>S_b</i>(<i>T</i>), which tends to unity as the doping decreases. The temperature dependence of the chain thermopower for several dopings has been determined from the measured in-plane thermopower and resistivity components, within the same model where the chains and planes conduct independently (ICPM). This temperature dependence is discussed within the usual Mott diffusion thermopower scenario. The c-axis thermopower has been measured for several dopings and is positive in magnitude and gradient, except at <i>T</i>*, where the gradient abruptly changes sign and the c-axis thermopower then becomes larger as the temperature is decreased.

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Systematic Raman scattering experiments were performed to compare the phonon properties in series of GICs BaC₆, SrC₆, YbC₆ and CaC₆. The key difference induced by changing the ions in this order is a reduction in the separation of the graphene layers, which is concurrent with an increase in the superconducting transition temperature <i>T_c </i>from &lt; 80 mK to 11.5 K. It was possible to correlate the increase in <i>T_c</i>with a softening of an out-of-plane carbon related phonon, which was explained in terms of increased charge in the carbon-related electronic band. This provides evidence that the carbon-related phonons and electronic-bands are crucial to the superconductivity in these compounds. An in-plane carbon phonon was also measured, which was shown not to follow the Born-Oppenheimer approximation. Recent theoretical attempts to explain these effects cannot fully account for the observed electron-phonon scattering rate. Neutron scattering was also used to measure the high energy carbon-related phonons in CaC₆. Due to the highly textured nature of the samples, special analytical techniques were developed to allow for the comparison between experiment and density functional theory (DFT). Overall, a good level of agreement between experiment and theory is found, which is significant in light of several other measurements of phonon related properties of CaC₆, which disagree with the theoretical predictions. YbC₆ was studied as a function of pressure to investigate the changes induced by reducing the layer separation. <i>T_c </i>initially increases consistent with the idea that moving the graphene layers closer increases <i>T_c</i>, however, at higher pressures <i>T_c</i> decreases disappearing at 7 GPa. These effects are discussed in light of a possible valence transition in YbC₆.

The aim of this project is to prepare and characterise novel triarylamine-based hole transport materials for xerographic applications that exhibit favourable electrochemical properties and amorphous nature. As an introduction, the six steps of the xerographic process and the common classes of hole transporting materials are described. The basic theories that have been developed for charge transport are discussed and an overview of the palladium-mediated amination and Suzuki reactions is given. In the following chapters, the synthesis and characterisation of a number of hole transporting triarylamines is reported. A series of linear trimeric arylamines is synthesised using the palladium-catalysed Suzuki protocol and their properties were determined using cyclic voltammetry, thermal gravimetric analysis and differential scanning calorimetry. Similar characterisation is carried out for a number of relatively unsubstituted phenyl and thiophene-based triarylamines. The synthesis of a series of oligomeric materials based on MPPD (Bis-methoxyphenyl-diphenyl-biphenyl-diamine) is reported and their electrochemical and thermal properties are investigated. Thiophene and dioctyl-fluorene-substituted MPPD-derivatives are studied as hole transport materials. Star-shaped and dendritic triarylamines with biphenyl and bithiophene-core molecules are also prepared using palladium-mediated chemistry and characterised. Finally, the attempts to synthesise macrocyclic triarylamine hole transporting materials are described in detail. The charge carrier properties for some of the synthesised materials are measured using the time-of-flight technique of using field-effect-transistors. Each set-up is described in detail and the hole mobility of the materials is calculated. A correlation between structural characteristics and charge-transporting properties is attempted.

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