The Fabrication And Characterization Of Palladium Composite Membrane By Chemical Fluid Deposition

Palladium composite membranes have attracted wide attention in membrane technology because of their excellent permeability, perm-selectivity and chemical and thermal stability. The dissertation discussed the principle and influence factors of hydrogen permeation, methods of construction for palladium-based membranes and their applications. The novel preparation technique under supercritical conditions was emphasized.In the paper we investigated the construction of palladium-based supported hydrogen separation membranes using Supercritical Fluid Deposition (SFD) with Pd(OAc)2 as precursor. Material microstructure and surface morphology were characterized using a variety of techniques including: SEM, XRD and EDX. The paper discussed the influence of reaction conditions: temperature, pressure, precursor concentration to the surface morphology and offered some techniques to improve it.The work demonstrated that Pd grains were found on the surface and within the substrates using ethanol or methanol as reactant and Pd(OAc)2 as precursor, though it showed little differences. The contents of Palladium increased through prolonging reaction time or increasing the reaction temperature, while reflective surface was seen using sodium hypophosphite as reactant. Annealed palladium microstructure within the porousα-alumina support is improved with 40ml/min CO2 blowing in and 400℃annealed 2h. A study of the surface seeding/activation step used throughout this work was presented. The support was pre-seeded with a catalytically active material and then deposited palladium membranes from supercritical carbon dioxide solution. Material microstructure and surface morphology vary significantly on seeded supports surface but no good at the deposition into the support pores. A same side continuous technique was used to study the preparing the palladium membranes.