Effect of the synthesis method on the properties and catalytic activities of Au/Pd nanoparticles supported on organophilic clay

• Organoclay supported Au/Pd nanoparticles were prepared by two different methods.
• Synthesis method affects composition, location and size distribution of particles.
• Metal nanoparticles were either located on the surface or within the clay layers.
• Intercalated monometallic particles are more active than external particles.
• External Au and Pd particles are more active than alloy intercalated particles.

Au and Pd mono and bimetallic nanoparticles supported on organoclay were prepared using two different approaches. In the first method (POST), the intercalated surfactant molecules were used as capturing and stabilizing agents of metal cations to prepare metal nanoparticles. In the second method (PRE), pre-made surfactant-stabilized metal nanoparticles were directly incorporated in the cationic clay. The structure and composition of the materials were probed by XRD, ICP-AES, XPS, CHN, TGA, and UV–Vis spectroscopy, while morphology was characterized by SEM. It was revealed that by the POST method, the particles remained majoritarily on the outer surface of the clay, while by the PRE method, the particles were intercalated. The materials were tested on the oxidation of benzyl alcohol, and the results showed that monometallic catalysts synthesized by the PRE method were more active. For the bimetallic materials, the activity was higher for the POST material, which was composed of AuPd alloy nanoparticles, while the PRE material was composed of isolated Au and Pd nanoparticles.

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