(696h) Hydrogen Permeable Membrane with Improved Separation Property

Yanying Wei,^1,2 Haihui Wang,² Jürgen Caro¹

¹ Institute of Physical Chemistry and Electrochemistry, Leibniz University of Hannover, Callinstrasse 3A, 30167 Hannover, Germany

² School of Chemistry and Chemical Engineering, South China University of Technology, 510640 Guangzhou, China

ceyywei@scut.edu.cn

High-temperature mixed proton and electron conductors (HT-MPECs) have attracted increasingly interest due to their wide potential applications as hydrogen sensors, hydrogen pumps, hydrogen permeable membranes for gas separation and catalytic membrane reactors, solid oxide fuel cells (SOFCs) etc. Materials with both high protonic and electronic conductivity, as well as adequate stability are required to be developed. BaCe_0.95Tb_0.05O_3-δ(BCT) is popular HT-MPECs, which exhibits the highest hydrogen permeation flux till now, but the instability due to the phase segregation hinders its applications. Considering the doped BaZrO₃ exhibits a much higher chemical stability compared with the doped BaCeO₃, and the two oxides can form easily a solid solution, the mixed proton and electron conductor material BaCe_0.85Tb_0.05Zr_0.1O_3-δ (BCTZ) is prepared through the glycine-nitrate combustion process, which exhibits enhanced stability for H₂ separation. Moreover, in order to improve the H₂ permeability of such material, metallic Ni is added as another phase for electronic conductor aimed to increase the electronic conductivity. Thus a Ni-BCTZ cermet membrane is synthesized by mixing the BCTZ oxide and the metallic Ni powder followed by sintering, which indicates good homogeneity of the perovskite oxide phase for protonic conductivity and the metallic Ni phase for electronic conductivity. After doping Zr into the BCT oxide, the chemical stability of both the BCTZ ceramic membrane and the Ni-BCTZ cermet membrane have been enhanced remarkably. The XRD and SEM results also prove the outstanding chemical stability, which promotes the Zr-doped Ba(CeTb)O_3-δ ceramic and cermet material as a proper candidate of an MPEC material for different potential applications.

Keywords:

Hydrogen separation/ Proton conductor/ Cermet membrane/ Perovskite/ Stability

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