Development of Mn and Mo double-substituted La5.5WO11.25-delta based membranes with enhanced hydrogen permeation flux

摘要

Mixed protonic-electronic ceramic lanthanum tungstate membranes of La5.5W1-xMnxO11.25-delta (LWMnx, x = 0.1, 0.15 and 0.2) and La5.5W0.8-yMn0.2MoyO11.25-delta (LWMn0.2Moy, y = 0.1, 0.2, 0.3 and 0.4) were developed in present work. The H2 permeation flux through lanthanum tungstate membrane was increased by substitution of Mn ions into W sites. However, the impurity of La2O3 formed in LWMn0.15 and LWMn0.2 membranes. Introduction of a moderate amount of Mo ions in LWMn0.2 was beneficial to single phase formation and H2 permeation. LWMn0.2Mo0.2 exhibited a pure cubic phase structure without any impurities. LWMn0.2Mo0.2 membrane had a H2 permeation flux about 0.12 mL/min center dot cm2 at 1000 degrees C, which was 1.7 times higher than that through LWMn0.2 membranes.