Carbonaceous nanoparticles and carbon on carbon composite materials : preparation, properties and application in adsorption

The inclusion of carbonaceous nanoparticles (CNPs) in composite materials is an area of significant research interest. Their addition is expected to result in differing properties, and a possible transfer of the CNP's favourable properties to the final composite. Detonation nanodiamond (DND) has emerged as an interesting CNP, offering an array of attractive properties, including mechanical stability, thermal conductivity and a flexible surface chemistry, that make it an ideal candidate for integration in composite materials. This material still requires further characterisation in order to fully understand its colloidal stability, aggregation behaviour and batchto-batch variability. The aim of the present thesis was to investigate DND as a new candidate for inclusion in the synthesis of novel carbon monolithic composite materials suitable for potential application in analytical chemistry, separation and adsorption processes, sensors or electrode materials. To address the variable nature of this CNP, new approaches for its characterisation and modification have been investigated. Capillary electrophoresis (CE) was shown to provide an insight into the onset of particle aggregation and offered the capability of separating DND from different sources or purification processes. Surface modification with silanes resulted in hydrophobisation and improved DND colloidal stability. After a detailed characterisation of these different DND materials, a commercial suspension of single-digit DND particles was selected for preparation of carbon on carbon composites. Hierarchical porous graphitic carbon-nanodiamond monoliths (CND) were prepared by adding DND to a resorcinol formaldehyde copolymer, with silica gel as a hard template. The influence of DND was systematically studied and for the first time it has been shown that altering DND content can allow for facile tuning of surface areas, pore sizes, and graphitic nature of carbon monoliths. The first controlled production of novel structures resulting from DND inclusion within the composite monoliths, such as carbon onions, has been achieved. Properties of CND composites including graphitic character, surface area, morphology, pore structures and adsorption performance for organic dyes were studied in detail. CND materials embody an interesting new group of carbon on carbon composite materials with potential for application in areas including adsorption, extraction, catalysis and electrode materials.