Deposition-precipitation synthesis, supported gold catalysts, preparation

Two synthesis methods were applied to prepare the TS-1 supports (TS-1 a and TS-lb). It was found that, after deposition of Au by precipitation method HDP-II, TS-1 a was a good catalyst, whereas catalyst TS-lb was totally inactive. In Figs. 1.15(a) and (b), TEM pictures of the Au-TS-1 samples are shown. The morphology of the two samples is quite different. TS-1 a consisted of very small crystallites (10 nm), agglomerated to form 150 nm particles, whereas TS-lb consisted of 35 pm crystals. The size of the gold particles in the TS-1 a sample with the small crystallites, was estimated to be 3-15 nm, which is not significantly smaller than those observed on the edges... 

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