Enhanced structural characterisation of supported catalysts

• Main Author: Price, Stephen William Thomas
• Other Authors: Russell, Andrea
• Published: University of Southampton 2011
• Subjects: 541.39; QD Chemistry
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539031

Complex materials are emerging for use in heterogeneous catalysis and electrocatalysis with order on the atomic scale. One of the central issues for continued growth in this area is the ability to precisely control the size and shape of the nanoparticles, especially for sub 10 nm particles. Understanding the structure of these materials is of key importance in understanding their activity and developing this precise control, with which the exploitation of the key properties of nanoparticles becomes possible. The body of the work conducted in this thesis aimed to provide more accurate characterisation of the size and shape of carbon supported nanoparticle catalysts. Both monometallic (Pt or Au) and bimetallic (PtPd) catalysts were studied. In the first results chapter the strengths and weaknesses of various structural characterisation methods, TEM, XRD and EXAFS were explored. Subsequent chapters focussed on improving the EXAFS analysis by (i) using molecular dynamics simulations as the inputs for structural fitting and (ii) by using a Cu UPD layer to cap the surface of the nanoparticles, thereby reducing the effects of termination of the metallic structure on the EXAFS. The latter study also enabled the Cu UPD structure on nanoparticles to be compared to that obtained on single crystal surfaces