Exceptional hydrogen permeation of all-ceramic composite robust membranes based on BaCe_0.65Zr_0.20Y_0.15O_3−δ and Y- or Gd-doped ceria

Abstract

Mixed proton and electron conductor ceramic composites were examined as hydrogen separation membranes at moderate temperatures (higher than 500 °C).

Hydrogen separation through tailored dual phase membranes with nominal composition BaCe0.8Eu0.2O3-δ:Ce0.8Y0.2O2-δ at intermediate temperatures

“…When both sides are humidified (configuration B), the obtained H 2 flow is one order of magnitude higher than in configuration A (0.4 mL·min −1 ·cm −2 at 700 °C). This important increase is attributed to the faster proton transport through the membrane, as a consequence of the higher hydration of the material and hence the higher concentration of protonic defects63. In addition to proton transport, H 2 is also generated at the sweep side by water splitting reaction mediated by the oxygen ion diffusion from the high p O 2 side (Ar sweep) to the lower p O 2 side (H 2 feed).…”

“…Medvedev et al 71. and Rebollo et al 63. have shown the chemical compatibility and stability of systems consisting of BaCe 1-x Ln x O 3-δ :Ce 1-x Ln x O 2-δ (x = 0.1–0.2) and BaCe 0.65 Zr 0.2 Y 0.15 O 3-δ :Ce 0.85 Ln 0.15 O 2-δ (Ln = Y, Gd), while Huang et al 72.…”

Catalytic activation of ceramic H2 membranes for CMR processes

“…It is noteworthy the significant H 2 fluxes obtained with several cermets as Ni-BaCe 0.9 Y 0.1 O 3- [11], Ni-BaZr 0.1 Ce 0.7 Y 0.2 O 3- [12] and Ni-BaCe 0.85 Tb 0.05 Zr 0.1 O 3- [13]. As well as the cer-cers based on BaCeO 3- or BaCe 1-x Zr x O 3- based materials as protonic phase and doped ceria as electronic phase [14,15].…”

“…This strategy has been widely employed for oxygen permeable membranes based on mixed ionic electronic conductors. [18][19][20][21] Regarding surface kinetics improvement in H 2 permeable membranes, the use of Pt as catalytic layer is the most reported for different materials as cerates [22], tungstates [23] and dual phase composites [14,24,25]. Ni and Pd particles were also employed for the coating of a BaCe 0.85 Tb 0.05 Co 0.1 O 3- perovskite hollow fibre membrane obtaining a significant H 2 flux improvement [26].…”

“…The reaction equilibrium can be shifted by controlled hydrogen removal with the consequent enhancement of separation, selectivity and yield of these reactions [5,6]. Dense mixed-conducting ceramic membranes are one of the typical inorganic membranes for CMR, specifically, mixed proton electron conducting membranes which present an important hydrogen permeability and catalytic activity at high temperatures [7,8]. Several ceramic membranes have been tested for water gas shift reaction at high temperature (700-900 °C) and the reported results are promising [9,10].…”