Highly controlled structuring of Pt nanoparticles on TiO2 and on ZrO2 by a modified MOCVD process
M. Faust, M. Seipenbusch
Surface and Coatings Technology 2014, 259, 577-584
The controlled structuring of platinum on well specified TiO2 and ZrO2 nanoparticles was achieved by fixed-bed MOCVD. Commercially available MeCpPtMe3 is shown to be very suitable for the production of well-defined Pt nanoparticles. The support materials were characterized by different methods, in order to measure adsorption sites on the surface. Fourier transform infrared spectroscopy was used to investigate the adsorption and decomposition of the precursor during the process. Dependent on the time of the cyclical precursor dosing and on the total duration of the CVD experiment different Pt particles of a defined median size between 1.3 nm and 2.8 nm and of a defined loading were synthesized using a two-step temperature program and flow reversion of the precursors. A decoupling of the control over particle size and loading was achieved. High Pt loading of up to 5.7 wt.% in combination with a small median Pt particle size of 2.1 nm was reached, which shows the unique potential of CVD as a structuring tool in catalyst development. Optimized process conditions, knowledge of the support particle surface and a well understood precursor decomposition mechanism allow for a very detailed understanding of the generation of the Pt nanoparticles which is prerequisite for an independent control of particle size and Pt loading.