Final Report Summary - NANOPARTCAT (Supported Nanoparticles for Catalysis: Genesis and Dynamics in the Liquid Phase)
In this project for the very first time we have used Transmission Electron Microscopy to study synthesis and assembly of supported metal catalysts in real time in the liquid phase. To this end we had to acquire a new transmission electron microscope (TEM) that allowed us to use a special cell and also to deliver high-quality elemental mapping. The special cell that we could use in TEM was acquired too. With this new equipment we had to take a number of hurdles before meaningful studies could be carried out. The electron beam in TEM may damage the sample in particular in liquid phase because of the formation of reactive radicals. We have found ways to suppress radical formation and also found the key aspects of materials to restrict damage in water. Having passed those hurdles we have studied a number of catalyst synthesis aspects. First, we have studied attachment of iron oxide nanoparticles to carbon nanotube support materials. These breakthrough studies revealed that the polarity of the carbon nanotubes greatly affects the nature and extent of interaction with the iron oxide nanoparticles. A second study involved the growth of gold nanoparticles on a titania support revealing for the very first time how the nanoscale growth appeared much more complex than predicted by macroscopic models of so-called Ostwald ripening. The third topic involved emplacement of noble metal nanoparticles, in particular platinum, on previously indicated locations in composite catalysts. This work has attracted worldwide attention since we could ‘steer’ Pt nanoparticle location to be either on one or the other component in bifunctional catalysts for alkane hydroisomerisation. This work has most recently been extended to lower noble metal loadings in composite catalyst without compromising their performance. The work has also attracted much interest and additional funding from industry.