The influence of carbon based supports and the role of synthesis procedures on the formation of platinum and platinum-ruthenium clusters and nanoparticles for the development of highly active fuel cell catalysts

A simple but effective solvent free method for the synthesis of platinum group metal nanoparticles on carbon nanotubes is presented. The initial work directly compares a typical wet chemical method and an organo-metallic chemical vapour deposition (OMCVD) technique for the production of 10 wt% Platinum on activated carbon and carbon nanotubes. The results obtained clearly showed that the wet chemical method produced materials with poorer physical-chemical characteristics and electrocatalytic activity. Also, carbon nanotubes were shown to be a more effective support regardless of the method of synthesis. Subsequent experimental work focused on the use of carbon nanotubes as a support, and the metal-organic chemical vapour deposition method as the synthesis technique. The method was successfully used to produce multiple samples with loadings of 20, 40 and 60 wt% Pt/CNT and a 40 wt% PtRu/CNT. HRTEM studies revealed stabilized clusters of platinum within CNT defects on samples synthesized using the OMCVD technique. The particle size distribution was relatively narrow, and the electrocatalytic activity was comparable or better than the benchmark Johnson Mathey 40 wt% Pt/C or 40 wt% PtRu/C.

► Simple and effective MOCVD synthesis method. ► Highly dispersed and very uniform Pt and PtRu nanoparticles on CNT supports. ► Clusters are stabilised by CNT defect sites. ► Homemade catalysts outperform benchmark JM catalyst.