The practical usefulness of this mechanism for the synthesis of supported catalysts hinges on whether the high dispersion of the monolayer-adsorbed precursor phase is maintained as the metal complex is reduced. To explore this hypothesis, a series of cationic noble and base metal ammines (Pt(II), Pd(II), Cu(II), Co(II), Ni(II), Ru(II), Ru(III), Rh(III)) was adsorbed at the high pH SEA condition over silica, and a series of anionic metal chlorides (Pt(IV), Pd(II), Cu(II)) was prepared at the low pH condition over alumina and compared to dry impregnation. The SEA-prepared materials consistently gave better dispersions of the reduced metals.
This method of preparation represents a simple way to prepare well dispersed metal particles over oxide and carbon with relatively cheap, common metal precursors. The method can also be extended for the “nano-engineering” of promoted and bimetallic catalysts.
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