Preparation and hydrogen permeation properties of Pd–Al₂O₃ matrix composites

Abstract

We propose Pd–Al₂O₃ matrix composites as hydrogen separators instead of pure Pd films. The Pd–Al₂O₃ is lower cost, more stable at higher temperatures as well as higher mechanical strength. The plasma electronic sintering method was effective for preparing 25(30) vol % Pd–Al₂O₃. The hydrogen permeation flux (J_H2) or total electrical conductivity (σ_t) of the 30 vol % Pd[with polyvinylpyrrolidinone (PVP)]–Al₂O₃ was one order of magnitude higher than that of the 25 vol % Pd(with PVP)–Al₂O₃, suggesting percolation conductions of 30 vol % Pd. The 30 vol % Pd(with no PVP)–Al₂O₃ was further higher than that of the 30 vol % Pd(with PVP)–Al₂O₃, because of connections among larger Pd grains for the sample with no PVP. The σ_t or J_H2 of the 30 vol % Pd(with no PVP)–Al₂O₃ was one magnitude lower than that of Pd films.