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 % Pr0.6Sr0.4FeO3-delta-60 wt % Ce0.9Pr0.1O2-delta (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 SO vol % CO2/50 vol % N-2 atmosphere. When using pure He or pure CO2 as sweep gases, at 950 degrees 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 degrees 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 CO2 atmosphere at high temperatures.