Palladium Membrane Coated with Zeolitic Armor Anchored by Diffusion-Piling To Enhance Performance

Herein, an innovative technique of diffusion-piling is proposed to nondestructively arm an ultrathin Pd membrane with a zeolite membrane. The effects of arming the Pd film with this zeolitic armor on the performances of H2 permeation and sulfur tolerance were evaluated, and the anchoring mechanism of the zeolite membrane onto the Pd film was discussed. For anchoring zeolite membrane onto the Pd film, coating an Al layer on the Pd film followed by a suitable thermal treatment to diffuse Al atoms into the Pd film are essential. Although the armed Pd film was covered with a zeolite membrane, its H2 permeation flux surprisingly increases under the applied conditions. In the test of H2S tolerance, after 250 min, the H2 permeance of the armed Pd membrane decreased by 61%, which is 25% higher than that of the bare Pd membrane. In particular, it is stable in the following test of 28 h, showing superior resistance to H2S poisoning.