Announcing the Final Examination of Azina Rahmani for the degree of Doctor of Philosophy
Noble metal catalysts are widely used for their remarkable activity and stability. However, their sustainability is challenged by their scarcity, both in terms of Earth-abundance and production sources. To ensure their sustainable use and long-term availability, it is essential to design new catalytic systems that minimize noble metal usage, maximize reactivity, and allow easy recovery and reuse. One promising approach involves using supported noble metal nanocatalysts (NCs) that enables low loadings of active materials, prevents NCs agglomeration during catalysis, and enhances separability of the catalysts from products. Nickel foams, as NCs support, stand out for their contiguous macroporous 3-D structure that guarantees full coverage of NCs, easy handling, stability, recyclability, cost-effectiveness, and availability. In this dissertation, we present facile approaches to prepare highly reactive, robust, and reusable noble-metal-based NCs encapsulated with a thin Al2O3 layer onto Ni foams. Design and synthesis of catalysts, reactivity scope, and selectivity sources in reaction systems are the main focus of this research. In the first project, Al2O3-coated Pt NCs on Ni foams were prepared and tested for the hydrogenation of various functionalized styrenes at mild reaction conditions in benign solvents. The material showed excellent catalytic activity and reusability, high tolerance towards F, Cl, and Br substituents, and no hydrogenation of the aromatic ring. Characterizations revealed ALD Al2O3 enhanced the stability of Pt NCs and NiOx nanoplates on the foam surface. In the second project, Al2O3-coated Pd NCs on dopamine treated Ni foams were prepared. The material demonstrated outstanding performance in hydrogenation of functionalized nitrobenzenes and styrenes at low temperatures and H2 pressure. The monolith material with evenly-coated Pd NCs proved to be highly robust and reusable. Finally, the membrane-like Pd-based catalyst was exploited to continuous flow hydrogenation of both styrene and nitrobenzene in a packed bed reactor.
Committee in Charge:
Dr. Titel Jurca (Chair)
Dr. Lei Zhai
Dr. Gang Chen
Dr. Xiaofeng Feng
Dr. Parag Banerjee
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