Preparation, Characteristics And Application In Hydrogen Permeation Of Proton Conductors

The dual-phase mixed proton-electron conductor hydrogen permeable membranes are denseceramic membranes with both protonic and electronic conductivities under hydrogen containingatmosphere at elevated temperatures. They have the advantages of in finite selectivity to hydrogen, sothey have potential applications in hydrogen production and alkaline conversion. Membrane materialsfor hydrogen permeation need to have stable phase composition at working temperature and in thereducing environment, good mechanical stability and high protonic conductivity.The dual-phase mixed proton-electron conductors Ba0.94Ce0.7Zr0.1Y0.1Yb0.1O3-δ/LaCo0.9Ni0.1O3(95:5,90:10,85:15,80:20,75:25), Ba0.94Ce0.7Zr0.1Y0.1Yb0.1O3-δ/Gd0.2Sr0.8FeO3-δ(90:10,80:20,70:30,60:40,50:50) and Ba0.94Ce0.7Zr0.1Y0.1Yb0.1O3-δ/Ce0.8Y0.2O2(80:20,70:30,60:40,50:50)were successfully synthesized by the solid state reaction method. The phase composition andmicrostructure of the samples were investigated by XRD and SEM. Chemical stability against CO2and boiling water was tested. The total conductivities of the samples in air, Ar and wet4%H2/Ar weremeasured by the electrochemical workstation. In addition, the hydrogen permeation fluxes of thesamples were measured in different hydrogen concentration and at different temperature by gaschromatographic method. The results indicate that:The three kinds of the dual-phase mixed proton-electron conductors form the desired dual-phasecomposition, and have good chemical compatibility. The samples are dense after sintered. Theaddition of ZnO as sintering aid improves the sinterability of the samples, saves the energy. Thechemical stability of the dual-phase mixed proton-electron conductor samples against CO2and boilingwater are improved and increases with increasing the content of electronic conductive phase. With theincreasing of electronic conductive phase, the conductivity in air, Ar and4%H2/Ar first decrease, thenincrease, and the conductance activation energy first increase, then decrease. The chemical stabilityand conductivity taken into consideration, Ba0.94Ce0.7Zr0.1Y0.1Yb0.1O3-δ/LaCo0.9Ni0.1O3(75:25),Ba0.94Ce0.7Zr0.1Y0.1Yb0.1O3-δ/Gd0.2Sr0.8FeO3-δ(60:40) and Ba0.94Ce0.7Zr0.1Y0.1Yb0.1O3-δ/Ce0.8Y0.2O2(60:40)are the best candidate for hydrogen permeable membranes which have the high protonic conductivityand the high electronic conductivity. The hydrogen permeation flux of the samples increases withincreasing test temperature and hydrogen concentration.