Fig. 3 shows TEM images of Cat. A, E, and J at both low and high magnification. The size distribution of loaded-Pt particles of Cat. A and E prepared was much narrower than that 3CAI of Cat. J. In the case of the catalysts prepared using w/o microemulsions, Pt particle density clearly increases with Pt content, even though particles with a similar size were loaded onto the support. No loaded Pt particles were visible for Cat. F because of the low Pt content. This fact consists with previous CO chemisorption results (Fig. 2).
Fig. 3. TEM images of (A) Cat. A (D-Pt(0.02)/940HOA), (B) Cat. E (D-Pt(0.18)/940HOA), (C) Cat. J (I-Pt(0.2)/940HOA.Figure optionsDownload full-size imageDownload as PowerPoint slide
It is evident mineralocorticoids the BET surface area was similar to the micropore surface area for all the catalysts (Table 2). This result indicates that the micropores were well developed. Fig. 2 shows that all the Pt catalysts, except for the impregnated catalyst with a Pt content of 0.01 wt% (Cat. F), have dpulse values greater than 2 nm. All the images indicate that most of the Pt particles exist in the support and the sizes are less than 50 nm ( Fig. 3). Taking these results into account, Pt particles of Pt-loaded catalysts in the present study were mainly loaded in the mesopores.