Novel Cobalt-Free, Noble Metal-Free Oxygen-Permeable 40Pr0.6Sr0.4FeO3-δ–60Ce0.9Pr0.1O2−δ Dual-Phase Membrane

A novel cobalt-free and noble metal-free dual-phase oxygen-transporting membrane with a composition of 40 wt % Pr 0.6 Sr 0.4 FeO 3−δ –60 wt % Ce 0.9 Pr 0.1 O 2−δ (40PSFO–60CPO) has been successfully developed via an in situ one-pot one-step glycine-nitrate combustion process. In situ XRD demonstrated that the 40PSFO–60CPO dual-phase membrane shows a good phase stability not only in air but also in 50 vol % CO 2 /50 vol % N 2 atmosphere. When using pure He or pure CO 2 as sweep gases, at 950 °C steady oxygen permeation fluxes of 0.26 cm 3 min –1 cm –2 and 0.18 cm 3 min –1 cm –2 are obtained through the 40PSFO–60CPO dual-phase membrane. The partial oxidation of methane (POM) to syngas was also successfully investigated in the 40PSFO–60CPO dual-phase membrane reactor. Methane conversion was found to be higher than 99.0% with 97.0% CO selectivity and 4.4 cm 3 min –1 cm –2 oxygen permeation flux in steady state at 950 °C. Our dual-phase membrane - without any noble metals such as Ag, Pd or easily reducible metals oxides of Co or Ni - exhibits high oxygen permeation fluxes as well as good phase stability at high temperatures. Furthermore, the dual-phase membrane shows a good chemical stability under the harsh conditions of the POM reaction and in a CO 2 atmosphere at high temperatures.