2012 年 63 巻 6 号 p. 365-
Platinum nanoparticle-supported activated carbon (Ketjenblack) was prepared in supercritical carbon dioxide solutions through hydrogen reduction reactions of bis-hexafluoroacetylacetonate-platinum (II). The dependence of temperature and reaction time on the particle size distribution was investigated, especially for particles smaller than 5 nm. Marked agglomeration of platinum was observed when the deposition temperature was high. Platinum nucleation took place mainly from 30 min to 60 min of the reaction time. Agglomeration and coarsening occurred mainly from 60 min to 90 min of the reaction time. The total volume of the platinum particles increased with increasing deposition temperature and reaction time.