Sodium borohydride, transition metal nanoparticles

TRANSITION METAL NANOPARTICLES CATALYST IN HYDROGEN GENERATION EROM THE HYDROLYSIS OE SODIUM BOROHYDRIDE ... 

TABLE 7.1 Transition Metal Nanoparticles Catalysts Employed in Hydrogen Generation from the Hydrolysis of Sodium Borohydride Activation Energy Ea of the Catalytic Hydrolysis and Activity of Catalyst in Turnover Frequency (TOF) or hydrogen generation Rate at 25 °C... 

Another approach for the preparation of dendrimer-noble metal nanoparticles in toluene is a process driven by acid-base chemistry and ion pairing [35]. At first, palladium nanoparticles are prepared by reducing aqueous K2PdCl4 with sodium borohydride in the presence of G4 dendrimer where the pH of dendrimer solution is adjusted to about 2. The low pH protonates the exterior amines to a greater extent than the less basic interior tertiary amines. Accordingly, Pd2+ binds preferentially to the interior tertiary amines and upon reduction palladium particles form within the dendrimer interior. After the complete reduction, the pH of solutions is adjusted back to about 8.5. Then, these nanocomposites can be quantitatively transported from the aqueous phase into toluene containing 10-20% of dodecanoic acid. The transition is visualized by the color change brown aqueous solution of dendrimer-palladium nanoparticles becomes clear after addition of the acid, while the toluene layer turns brown. 

Metal particles are most conveniently grown on the clay mineral surface by displacing the exchangeable cation by precursor transition-metal cations and by subsequent reduction. Au and Ag clusters were obtained in laponite clay mineral of synthetic origin by Aihara et al. [9] using this method with sodium borohydride as a reducing agent. Silver nanoparticles are widely used as photosensitive components [10], as catalysts [11], in photocatalysis [12], and in surface-enhanced Raman... 

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