Chemical stability and hydrogen permeation performance of Ni-BaZr0.1Ce0.7Y0.2O3_δ in an H2S-containing atmosphere

Composite membranes based on Ni and Zr-doped BaCeO3 are promising for hydrogen separation. Such composites show high proton conductivity and adequate chemical stability in H2O and CO2, but may be unstable in H2S. The hydrogen permeation performance of Ni-BaZr0.1Ce0.7Y0.2O3-delta was measured in an H2S-containing atmosphere at 900 C. The hydrogen permeation flux began to degrade in 60 ppm H2S and decreased by about 45% in 300 ppm H2S. After hydrogen permeation tests, XRD revealed the formation of BaS, doped CeO2, Ni3S2 and Ce2O2S. Analysis of the microstructure and phase composition, and results of thermodynamic calculations suggested that the reaction between H2S and doped BaCeO3 caused the performance loss of the Ni-BaZr0.1Ce0.7Y0.2O3-delta. 20 refs.