Influence of the precursor on fullerene synthesis in a RF thermal plasma reactor

Abstract

Several graphite powders and mixtures (4827 Asbury Mills, KS4 and KS6 Timcal flake Alfa Aesar, graphite Aldrich, mixture of iron and KS4 powder) having different mean particle size were processed in a RF thermal plasma reactor at atmospheric pressure. It was found that the mean particle size of the precursors has an important, but not exclusive effect on the evaporation efficiency. The micro-structural orderliness of the precursors, which determines their thermal conductivity, is another important property that should be considered in the interpretation of the observed phenomena. In this study a mixture of iron and KS4 graphite proved to be the best precursor of fullerene synthesis. The maximum fullerene yield was 18.4%, which was higher compared to pure graphite powder processing in a RF reactor without the presence of iron.U termijskom RF plazma reaktoru pod atmosferskim pritiskom procesuirano je nekoliko grafitnih prahova i njihovih smesa (4827 Asbury Mills, KS4 i KS6 Timcal, Alfa Aesar, grafitni Aldrich, smesa gvozdja i KS4 praha) sa razlicitom raspodelom velicina cestica. Utvrdjeno je da srednja velicina cestica ima znacajan ali ne i jedini uticaj na efikasnost otparavanja. Mikro strukturna nesredenost prekursora, koja utice na njegovu termijsku provodljivost, takodje je vazna osobina koja se mora uzeti u obzir pri objasnjenju uocenih fenomena. Kao najbolji prekursor za sintezu fulerena pokazala se smesa gvozdja i grafitnog praha KS4. Maksimalni prinos fulerena bio je 18,4%, veci nego u slucaju cistih grafitnih prahova tretiranih u RF plazma reaktoru bez prisustva gvozdja.