Optimization and characterization of electroless co-deposited PdRu membranes: effect of the plating variables on morphology

FERNANDO BRAUN, ANA M. TARDITI, LAURA M. CORNAGLIA

JOURNAL OF MEMBRANE SCIENCE

ELSEVIER SCIENCE BV

Año: 2011 vol. 382 p. 252 - 261

0376-7388

PdRu films were successfully synthesized on top of non-porous stainless steel supports by electroless co-deposition. The effect of synthesis variables on morphology, substrate adherence, bulk and surface composition were studied. The microstructure and morphology of the samples were analyzed by X-ray diffraction and scanning electron microscopy. Homogeneous and defect-free PdRu films were obtained employing baths at low pH, moderate to high agitation speeds, high concentration of hydrazine, using EDTA as a stabilizer and temperatures near 50 ºC. Films characterized by X-ray photoelectron spectroscopy showed Pd segregation after annealing the sample at 400 ºC in H2 (5%)/ Ar in the load-lock chamber of the spectrometer. The optimized conditions were employed to synthesize a PdRu composite membrane on top of a tubular porous stainless steel substrate (0.1 micron grade). Hydrogen permeation was measured over a 350 – 450 ºC temperature range and a trans-membrane pressure up to 100 kPa. The PdRu membrane showed good performance with a hydrogen permeability of 6.5 x 10-9 mol m-1 s-1 Pa-0.5 and a selectivity higher than 1700