Immobilization Of Pd Nanoparticles Research Articles

Preparation and structural properties of Pd nanoparticles in layered silicate

Pd nanocrystals in the 5–15 nm ranges were prepared on pillared clay minerals (PILCs) as supports by immobilizing Pd nanoparticles in the interlamellar space of montmorillonite and saponite by pillaring with aluminium hydroxide cations. Pd nanoparticles were generated via reduction by ethanol of Pd acetate present in the adsorption layer at room temperature. The structure of Pd-PILC samples was characterized by XRD and N 2 gas sorption measurements. The Pd/H interaction was characterized by H 2 sorption isotherms, which revealed extensive sorption hysteresis depending on particle size. This effect calls attention to the potential use of Pd-PILC adsorbents for storage of gaseous H 2. Microcalorimetry was carried out to determine H 2 gas sorption enthalpy isotherms, which also exhibited a sorption hysteresis. By combining the data, H/Pd interactions are also expressed as molar sorption enthalpies. It is concluded that, due to differences in surface accessibility for hydrogen, H/Pd interactions are determined by the joint effect of the external to total atomic ratio of Pd nanoparticles and the microporosity of the support pillared clays.

Enzyme and chemical encapsulation in polymeric microcapsules

Abstract : Polypyrrole microcapsules (prepared via the template method) were used for immobilization of both enzymatic and chemical catalytic systems. Enzymes immobilized include glucose oxidase, catalase, trypsin, subtilisin, and alcohol dehydrogenase. The chemical catalytic system investigated consisted of immobilized Pd nanoparticles for catalysis of hydrogen peroxide decomposition. Microcapsules loaded with glucose oxidase (GOD) were found to have higher enzymatic activity than GOD-loaded thin films, a competing encapsulation method. Trypsin was used to explore the possible leakage of small proteins from the capsules; no leakage was observed. Subtilisin was used to show that these microcapsules can be used in non-aqueous solvents. The effect of capsule wall thickness on the rate of enzymatic reaction was also explored.