On 27 August at 13:15 Sajid Hussain will defend his doctoral thesis „Electrochemical reduction of oxygen on supported Pt catalysts” for obtaining the degree of Doctor of Philosophy (in chemistry).
Assistant Professor Kaido Tammeveski (PhD), Institute of Chemisrty, University of Tartu
Senior Research Fellow Nadežda Kongi (PhD), Institute of Chemisrty, University of Tartu
Research Fellow Heiki Erikson (PhD), Institute of Chemisrty, University of Tartu
Assistant Professor Annukka Santasalo-Aarnio (PhD), Aalto University, Finland
The aim of this study is to improve the electrocatalytic activity and lifetime of the platinum catalyst supported on carbon-based materials for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. Various methods were employed for the deposition of platinum nanoparticles on the support such as magnetron sputtering, electrochemical deposition, chemical synthesis and photo-deposition. Surface characterisation of the prepared electrocatalysts was performed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) analysis, cyclic voltammetry and CO stripping experiments. The kinetics of the ORR has been thoroughly studied employing the rotating disk electrode (RDE) method. In the first part of the PhD studies, platinum nanoparticles were deposited on carbon-based support materials such as multi-walled carbon nanotubes and modified graphene nanosheets, the electrochemical measurements were carried out in both alkaline and acidic solutions. The second part of the research was devoted to investigate the activity and durability of platinum nanoparticles supported on metal oxide-carbon composites. Electrochemical results revealed that incorporating metal oxide (TiO2 or SnO2) into the carbon-based support materials increases the electrocatalytic activity and durability of the catalysts by the strong metal-support interaction.
All the different types of electrocatalysts prepared and investigated in this work showed remarkable ORR activity and better long-term durability than that of the commercially available 20 wt.% Pt/C catalyst