Fabrication of AuPd bimetallic nanoparticles and their effects on hydrogenation reactionsTools B. F. Pinto, Jose Jorge (2021) Fabrication of AuPd bimetallic nanoparticles and their effects on hydrogenation reactions. PhD thesis, University of Nottingham.
AbstractAs catalytic reactions reach nearly 40 % of the world GDP, enhancing the catalytic properties of scarce metals, generating highly active, selective and durable catalysts is critical. Bimetallic AuPd NPs present enhanced activity and selectivity in hydrogenation reactions. However, the mechanisms behind their improved catalytic properties when compare to their monometallic counterparts and the enhancement effect of Au in the alloy remains ambiguous. This thesis elucidates the synergetic effect in AuPd NPs leading to their enhanced catalytic properties towards the selective hydrogenation of CAL. The AuPd NPs were first co-deposited in IL ([C4C1Im][NTf2]) by magnetron sputtering and their structural and electronic properties characterised. Evidence of the interaction of both metals with the disruption of the Au surface plasmon resonance in the presence of Pd (UV-vis) was observed and the absence of the Au-IL interaction with the increase of Pd content (XPS). XAS experiments confirmed the presence of a core-shell structure in the AuPd NPs with the preferential interaction of the SO2 groups in the IL anion with the sputtered Pd atoms leading to an ordering of the NP structure during growth and nucleation. Highest conversion was obtained after 24h with Au0.5Pd0.5 (85%) in comparison to Pd1 (36%). The effect of the both the reagents and products on the catalytic activity of the Au0.5Pd0.5 and Pd1 catalysts was evaluated using VTNA determining a Langmuir-Hinshelwood mechanism and differences in stability of both catalysts over time. The presence of Au in the AuPd NP in IL, leads to an increase in the robustness of the catalyst, increasing the H2 activation on the catalyst surface and decreasing the dependency on the [CAL] and [H2].
Actions (Archive Staff Only)
|
Tools
Tools
