Palladium and palladium alloy composite membranes prepared by metal-organic chemical vapor deposition method (cold-wall)

Thin Pd and Pd-Ni alloy membranes were prepared by the MOCVD method using a n cold-wall technique. Pd(C3H5)(C5H5) and Ni(C3H5)(C5H5) were decomposed in to densely aggregated metal crystallites that were to plug mesoporous nicke l-stainless steel (Ni-SUS) or gamma-Al2O3/alpha-Al2O3 supports. The use of highly volatile organometallic precursors enabled continuous and controlled deposition mode, which resulted in reproducible formation of thin impervio us Pd or Pd-Ni alloy membranes. Pd(C3H5)(C5H5) and Nb(C3H5)(C5H5)(5) were d eposited in a layer by layer deposition method. The H-2 permeance of the Pd /Ni-SUS membrane was 2.0-5.0x10(-2) cm(3) cm(-2) cmHg(-1) s(-1) (723 K); th e H-2/N-2 selectivity was 1600. The H-2 permeance of the Pd/Al2O3 was 1.5x1 0(-2) cm(3) cm(-2) cmHg(-1) s(-1) (723 K); the H-2/N-2 selectivity was > 10 00. (C) 2000 Published by Elsevier Science B.V.