Growth of Pd nanoparticles on layer silicates hydrophobized with alkyl chains in ethanol-tetrahydrofuran mixtures

The surface of montmorillonite, a hydrophilic layer silicate, was modified with alkylammonium and alkylpyridinium cations with the aim of producing Pd nanoparticles within the hydrophobized interlamellar space. The structure and interlamellar swelling of hexadecylpyridinium and tetradodecylammonium montmorillonite were first studied in tetrahydrofuran-ethanol mixtures. It was established that both hydrophobic montmorillonites swell readily in tetrahydrofuran and the interlamellar spaces may be employed as nanoreactors for the synthesis of Pd^o particles. Ethanol was adsorbed on the surface of the hydrophobic support. After addition of the precursor Pd-acetate, metallic Pd was produced on the external and internal surfaces of the support. The diameter of the particles formed was in the range of 2-5 nm as shown by TEM.