| Based on the observation of the microstructure of palladium deposited on a porous stainless steel surface using an electroless process, we find that the palladium membrane is made of nanoparticles and its thickness is directly dependent on the size of the nanoparticles. The size of palladium nanoparticles can be effectively controlled by concentration of PdCl2 in the plating solution. The higher concentration of PdCl2 in the plating bath will result in a smaller size of palladium particles deposited on the substrate. The smaller the size of palladium nanoparticles is generated from the solution, the thinner the dense palladium membrane is built. The result obtained from hydrogen permeation through the ultra-thin palladium membrane having a thickness of 400 nm demonstrates that this ultra-thin membrane is solid and it can be used at the temperature of 550 °C and hydrogen pressure difference of 50 psi. These experimental results will allow optimizing the design of an ultra-thin palladium membrane for hydrogen extraction. |
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