6533b7d4fe1ef96bd1261f8a
RESEARCH PRODUCT
Preparation of Pd coated anodic alumina membranes for gas separation media
Maurizio VolpeCarmelo SunseriMariateresa AmodeoRosalinda InguantaFabio D'agostinoSalvatore Piazzasubject
ChromatographyAluminaAmorphous materialsDissolutionPalladiumPlatingRenewable Energy Sustainability and the EnvironmentChemistryCondensed Matter PhysicsSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsAmorphous solidMembraneSettore ING-IND/23 - Chimica Fisica ApplicataChemical engineeringPlatingMaterials ChemistryElectrochemistryGas separationSolubilityDissolutionDeposition (chemistry)Layer (electronics)description
Different procedures of Pd electroless deposition onto anodic alumina membranes were investigated to form a dense metal layer covering pores. The main difficulty was related to the amorphous nature of anodic alumina membranes, determining low chemical stability in solutions at pH > 9, where Pd plating works more efficiently. As a consequence, it was necessary to find the operative conditions allowing Pd deposition without damaging the membrane: to reduce alumina dissolution, the plating bath was buffered at pH 8.5 by addition of either NaHCO 3 or Na 2 B 4 O 7 ·H 2 O. Acceptable conversion of Pd was found after a deposition time of 3 min. Single and multiple deposition steps (each lasting 3 min) were accomplished. After five deposition steps, pores remained open in the plating bath containing NaHCO 3 , while they were almost totally occluded in the bath containing Na 2 B 4 O 7 ·H 2 O. In this last bath, a dense layer of Pd, ∼ 1 μm thick, was obtained after four deposition steps alternated with surface reactivation steps; the complete closure of pores was confirmed by gas permeability measurements. The different behavior of the two buffers can be attributed to a higher solubility of amorphous alumina in NaHCO 3 solution.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2007-01-01 |