This thesis describes applications of advanced multinuclear solid-state nuclear magnetic resonance (NMR) experiments to the characterisation of industrially-relevant catalyst materials. Experiments on γ-Al₂O₃ introduce the use of solid-state NMR spectroscopy for the investigation of disordered solids. The existence of Al(V) sites on the surface of this material is demonstrated, showing that removal of adsorbed H₂O may facilitate a rearrangement effect in γ-Al₂O₃ that promotes the formation of these Al environments. A range of aluminium oxide-based supported metal catalysts has been investigated. Studies of these systems by ¹H and ²⁷Al solid-state NMR spectroscopy indicate that a metal-support interaction (MSI) exists between surface cobalt oxide crystallites and the γ-Al₂O₃ support, and is strongest for materials containing small, well dispersed Co oxide crystallites. It is shown that the hygroscopic nature of γ-Al₂O₃ allows the extent of the MSI to be visualised by ¹H MAS NMR, by observing the extent of the proton-metal oxide interaction resulting from the presence of adventitious adsorbed H₂O. The surface/bulk chemistry of Co spinel aluminate materials is also investigated. ¹H, ²⁹Si, ²⁷Al and ¹⁷O solid-state NMR techniques are used to gain insight into the structural nature of silicated alumina catalysts. The combination of isotopic enrichment and dynamic nuclear polarisation (DNP) surface-enhanced NMR spectroscopy can provide a definitive and fully quantitative description of the surface structure of Si-γ-Al₂O₃ (1.5 wt% Si), and the role of adventitious surface water is highlighted. Analysis of silicated aluminas prepared by “sequential grafting” and “single shot” approaches shows that silica growth on γ-Al₂O₃ follows two distinct morphologies. ¹⁷O gas exchange enrichment is also shown to be successful in facilitating ¹⁷O solid-state NMR studies of these materials. It is demonstrated that double (²⁹Si and ¹⁷O) enrichment of Si-γ-Al₂O₃ (1.5 wt% Si) can facilitate access to ²⁹Si-¹⁷O 2D correlation experiments, even at low silica loading. An exploratory investigation of Ti-alumina model catalysts has also been carried out using ¹H, ²⁷Al and ¹⁷O solid-state NMR spectroscopy. These studies indicate that Ti-γ-Al₂O₃ and Ti-Al M50 may be structurally distinct materials.

[pt] O controle de parâmetros físicos e químicos das nanopartículas, tais quais, forma, composição e tamanho, além da interação entre metal e suporte, são fatores determinantes no desenvolvimento de um nanocatalisador com uma boa performance. Desse modo, nanopartículas de ouro foram incorporadas em nanofios de céria e utilizados como nanocatalisador para a oxidação seletiva do tioanisol. Sendo a sua morfologia 1D, com grande área superficial específica, diâmetros finos, alta concentração de vacância de oxigênio e pequenas NPs de Au uniformemente distribuídas na superfície do CeO2, além de espécies oxidadas de ouro, temos em nosso material características que o torna favorável a reação de oxidação. Os nanofios de CeO2-Au demonstraram uma melhora na performance da oxidação seletiva do tioanisol quando comparados aos nanofios de céria puros, e ao material comercial com e sem a deposição de NPs de Au. Os nanofios de céria obtiveram uma seletividade de 100 porcento para o metil fenil sulfóxido, e uma conversão de 53 porcento em 2 h de reação. O impacto da temperatura também foi observado, demonstrando que esse é, também, um fator importante na análise da atividade de um catalisador. / [en] The control over physical and chemical parameters of nanoparticles, such as shape, composition and size as well as the interactions between metal and support, are important factors in the development of a nanocatalyst with high activity. In this context, gold nanoparticles were incorporated the surface of ceria nanowire for application as nanocatalysts towards the selective oxidation of thioanisole. Considerin their one-dimensional morphology, high specific surface area, thin diameters, significant concentration of oxygen vacancies, and small Au NPs uniformly deposited at the CeO2 nanowires surface, our material displayed characteristics that makes them favorable for oxidations reactions. The CeO2-Au nanowires showed improved catalytic performances in the selective oxidation of thioanisol relative to pure CeO2 nanowires and commercial CeO2 with and without Au NPs deposited. CeO2-Au nanowires catalyzed the desired product with 100 percent of selectivity and 53 percent of conversion. The impact of temperature, such as the solvent, were also observed revealing that these factors also influences in the activity of these nanocatalyst.