Ceramic proton-conducting oxide membranes are described herein, which are useful for separating steam from organic chemicals under process conditions. The membranes have a layered structure, with a dense film of the perovskite over a porous composite substrate comprising the perovskite material and a metallic material (e.g., Ni, Cu, or Pt). The perovskite comprises an ABO3-type structure, where “A” is Ba and “B” is a specified combination of Ce, Zr, and Y. The perovskite ceramic materials described herein have an empirical formula of Ba(CexZr1-x-nYn)O3-δ, wherein 0