John Watt

John Watt

Job Title

Associate Investigator

Biography

My research area is the synthesis, characterisation and catalytic studies of complex shaped nanostructures. The application of catalytically active metal nanostructures includes fuel cell catalysts, hydrogen storage and sensing applications. Nanoscale catalysts of platinum, gold, palladium and ruthenium currently hold much interest for these applications due to an increase in catalytic activity whilst reducing the amount of precious metal used. It is well known that by increasing the number of high index, high energy surfaces, the catalytic activity increases and that different crystallographic faces offer differing catalytic specificity. Therefore catalytically active nanostructures also allow for the tuning of activities and specificities by controlling the resulting shape. Furthermore, bimetallic (core-shell or alloyed) nanostructures offer increased activity through catalytic synergy. Catalytic synergy occurs when two different catalytically active metals are in close contact with each other and can lead to huge improvements in activity when compared to individual metals. It can also lead to increases in stability and a lower operating temperature which is an advantage for the application of high surface area nanostructured catalysts. Current focus is on bimetallic nanostructures formed through a galvanic exchange reaction. In this approach complex nanostructures are used as templates for the nucleation and growth of secondary metals on the surface while the template is sacrificed in the exchange. This will lead to complex nanostructures of a wide range of metals with fine control over their size and shape. Furthermore, the metal to metal ratio can be carefully controlled to investigate the effects of catalytic synergy. This work is in collaboration with Assoc Prof. Richard Tilley (PI). Preliminary catalytic studies will be performed at Victoria University of Wellington with promising materials being forwarded to an international collaborator (Dr James Cookson, Johnson Matthey, UK) for extensive catalytic testing. I have visited Dr Cookson on two occasions setting up and building this collaboration. Certain nanostructures will also be characterised using synchrotron facilities (Dr Mike Toney, Stanford Synchrotron Radiation Laboratory) and a double aberration corrected transmission electron microscope at Oxford University (Prof. Angus Kirkland).

Expertise
  • Inorganic hybrid materials