Electronic Structure, Stability, and Chemical Reactivity of Transition-Metal Catalysts Supported by Graphene Nanomaterials
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- Institutt for kjemi 
Graphene, a 2D monolayer of graphite, has emerged as a novel material in many areas, such as catalysis and energy storage devices. Because of fascinating properties, such as remarkable surface area, superior electric conductivity, excellent mechanical strength, and high thermal stability, graphene and its derivatives are considered to be promising support materials for the next generation of nanocatalysts, especially in fuel cells. The research interest on materials for catalytic applications focuses on designing catalysts with higher utilization efficiency and lower content of precious metals. Graphene-based nanomaterials are at the forefront of chemical research to achieve this goal. A fundamental understanding of the interactions between the catalyst and the support material is of critical importance in heterogeneous catalysis. The main objective of this dissertation is to provide a systematic investigation on the properties of transition metal (TM)-graphene nanocomposites using density functional theory (DFT) calculations. In particular, electron transfer through the interface and the consequence to the catalytic properties of the TM-graphene nanocomposites is the main challenge. Hence, we systematically investigate the structural and electronic properties of platinum (Pt) and cobalt (Co) singleatoms and dimers interacting with polyaromatic hydrocarbons (PAH), as the graphene model, and elucidate the nature of these interactions. The role of support materials and the effects of surface functionalization on the stability and catalytic activity of Pt catalysts are investigated. CO poisoning is a key issue in catalysis, hence, the CO molecule is used as a probe to investigate the adsorption properties on the supported Pt catalyst. The results suggest that tailoring the carbon support materials using oxygen-containing groups can enhance the resistance of Pt/C catalysts to CO poisoning. Finally, we investigate the detailed kinetic mechanisms for C–H, O–H, C–C, and C–O bond cleavages of ethylene glycol on Pt13 cluster. Our results demonstrate that Pt13 can be a better catalyst than a Pt surface for production of hydrogen from biomass materials.