Hydrogen permeation through thin supported SrZr0.2Ce0.8−xEuxO3−δ membranes

SrZr0.2Ce0.8−xEuxO3−δ (x = 0.1 and 0.15) membranes were investigated for their hydrogen permeation properties as a function of membrane thickness, from 17 to 50 μm. Membrane permeation flux was proportional to [PH2]1/4[PH2]1/4 matching Norby and Larring's model when protons and electrons are the dominating defects. The observed inverse linear dependence of flux with membrane thickness indicates bulk diffusion is the rate-limiting factor for hydrogen permeation. After correcting for water formation, higher Eu doping in the membrane was confirmed to result in greater hydrogen flux, consistent with our previous conductivity studies. A H2 flux of 0.35 cc/min cm2 was achieved for 17 μm thickness SrZr0.2Ce0.7Eu0.1O3−δ membrane at 900 °C and 100% H2 in the feed gas. However, taking observed water vapor formation into consideration, a maximum H2 flux of 0.50 cc/min cm2 was achieved under the same conditions.