Preparation of palladium-coated V and V-15Ni membranes for hydrogen purification by electroless plating technique

摘要

A simple electroless palladium plating treatment on V and V-15Ni alloy was attempted to prepare sandwich-type membranes for hydrogen purification. The obtained coating on the membranes was characterized using SEM-EDX and AFM, and hydrogen permeability and hydrogen diffusion coefficients for the plated membranes were determined. Sensitizing-activating treatment with SnCl_2 and PdCl_2 solutions before the electroless plating treatment enabled palladium to cover the membranes densely. The V membrane with electroless palladium plating, whose hydrogen permeability was 5.0 x 10~(-7) mol H_2 m~(-1) s~(-1) Pa~(-1/2) at 623 K, showed cracking during the hydrogen permeation experiment at 473 K. Hydrogen permeability for the V-15Ni membrane with electroless palladium plating was 3.4 x 10~(-8) mol H_2 m~(-1) s~(-1) Pa~(-1/2) at 623 K, which was comparable to that of the sample coated by the conventional methods including evaporation and electrochemical plating. The long-period permeation test showed that the V-15Ni membrane with electroless palladium plating possessed satisfactory durability to be used as hydrogen purification material.