Herein discussed is a method of using an oxide ion conducting membrane comprising exposing the oxide ion conducting membrane to a reducing environment on both sides of the membrane. In an embodiment, the oxide ion conducting membrane also conducts electrons. In various embodiments, the membrane is impermeable to fluid flow (e.g., having a permeability of less than 1 micro darcy). In an embodiment, the oxide ion conducting membrane comprises lanthanum chromite and a material selected from the group consisting of doped ceria, yttria-stabilized zirconia (YSZ), lanthanum strontium gallate magnesite (LSGM), scandia-stabilized zirconia (SSZ), Sc and Ce doped zirconia, and combinations thereof. In an embodiment, the lanthanum chromite comprises undoped lanthanum chromite, strontium doped lanthanum chromite, iron doped lanthanum chromite, strontium and iron doped lanthanum chromite, lanthanum calcium chromite, or combinations thereof. In an embodiment, the membrane is mixed conducting.