| AVS 60th International Symposium and Exhibition | |
| Plasma Science and Technology | Thursday Sessions |
| Session PS+AS+NS+SS-ThM |
| Session: | Plasma Synthesis of Nanostructures |
| Presenter: | D. Merche, Univ. Libre de Bruxelles, Belgium |
| Authors: | D. Merche, Univ. Libre de Bruxelles, Belgium T. Dufour, Univ. Libre de Bruxelles, Belgium L. Devant, Facultés Univ. Notre Dame de la Paix, Belgium F. Deschamps, Univ. de Liège, Belgium J.-J. Pireaux, Facultés Univ. Notre Dame de la Paix, Belgium L. Houssiau, Facultés Univ. Notre Dame de la Paix, Belgium N. Job, Univ. de Liège, Belgium F.A.B. Reniers, Univ. Libre de Bruxelles, Belgium |
| Correspondent: | Click to Email |
The grafting of noble metal nanoparticles on porous carbon supports has attracted a great interest over the last few years, due to potential applications in Proton Exchange Membrane Fuel Cells (PEMFC). Plasma processes for the synthesis of such electrodes could be a major asset for the production of the fuel cell elements at lower cost.
In this study, Pt nanoparticles are synthesized from the decomposition of Platinum (II) acetyle acetonate [Pt(acac)2] and deposited on porous carbon by the means of an RF atmospheric plasma torch running with argon in an open air environment. This one single step technique is very simple, fast and robust. It also presents substantial economic advantages, such as the non requirement of a high-vacuum and the possibility to easily implement this process in a continuous production line. The Pt nanoparticles were principally grafted on carbon-black powder. Some tests were also conducted on Carbon Xerogel matrices presenting well-controlled porosity.
The organometallic-carbon powder mixture pressed on a copper tape was treated in the post-discharge of the Ar plasma torch. A kinetic study has been carried out by XPS to evaluate the optimal exposure time to the post-discharge required for synthesizing a significant amount of Pt nanoparticles. 6% of Pt was detected after only 30 seconds of plasma treatment, and 14% after 600 seconds. According to the fitting of the Pt XPS peaks, the most intense component of the Pt for the sample treated by plasma was the Pt(0). 68% of the platinum was under metallic form after 30 seconds of plasma treatment, and 78 % after 600 seconds.
The effect of the distance between the powder and the torch, and the addition of a small quantity of hydrogen to the vector gas was studied by XPS regarding the elemental composition and the oxidation state of the platinum nanoparticles. A comparison with Pt synthesized in a controlled atmosphere was also realized. For a study more focused on the PEMFC applications, the powder mixture was overlayed on a Gas Diffusion Layer (GDL), namely Carbon Toray Paper (CTP), before being exposed to the Ar post-discharge.
The size and the dispersion of the nanoparticles grafted on carbon black powder or on carbon Xerogel were observed by a FEG-SEM and by TEM.