Generation of Pt- and Pt/Zn-containing ceramers and their structuring as macro/microporous foams

• Generation of hierarchical ordered macro/microporous structures by direct foaming.
• High specific surface area due to an extended microporosity.
• Adjustable hydrophilic/hydrophobic surface properties by pyrolysis temperature.
• In situ formation of Pt and bimetallic Pt/Zn nanoparticles.
• Analysis of Pt and Pt/Zn nanoparticles in CO oxidation.

In this work, a simple method is presented to generate hierarchically structured monolithic types of foam with high specific surface areas and good catalytic activities in a one-step process. The materials prepared are platinum- and zinc/platinum-containing hybrid ceramics generated by the pyrolytic conversion of a mixture of a methyl phenyl polysiloxane, 3-aminopropyltriethoxysilane, platininc acid or platinic acid, and a zinc salt. Foam structures are prepared by using a modified azodicarbonamide as the blowing agent and investigated in comparison to granulated samples. The low pyrolysis temperatures of 500 °C and 600 °C lead to porous materials with specific surface areas of 300–560 m2 g−1 due to microporosity, so that in the case of the foam structures, hierarchically ordered macro/microporous materials are generated. Furthermore, it can be shown that the platinum is present as nanoparticles and the surface characteristic and catalytic activity in CO oxidation experiments are strongly dependent on the pyrolysis temperature and the presence of zinc.

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