| abstract |
In one embodiment, a membrane of proton-electron conducting ceramics that is useful for the conversion of a hydrocarbon and steam to hydrogen has a porous support of M′-Sr 1-z′ M″ z′ Ce 1-x′-y′ Zr x′ M′″ y′ O 3-δ , Al 2 O 3 , mullite, ZrO 2 , CeO 2 or any mixtures thereof where: M′ is Ni, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Nb, Mo, W, Zn, Pt, Ru, Rh, Pd, alloys thereof or mixtures thereof; M″ is Ba, Ca, Mg, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, or Yb; M′″ is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Nb, Mo, W, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, or Yb; z′ is 0 to about 0.5; x′ is 0 to about 0.5; y′ is 0 to about 0.5; and x′+y′>0; for example, Ni—SrCe 1-x′ Zr x′ O 3-δ , where x′ is about 0.1 to about 0.3. The porous support is coated with a film of a Perovskite-type oxide of the formula SrCe 1-x-y Zr x M y O 3-δ where M is at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Nb, Mo, W, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb, x is 0 to about 0.15 and y is about 0.1 to about 0.3. By including the Zr and M in the oxide in place of Ce, the stability can be improved while maintaining sufficient hydrogen flux for efficient generation of hydrogen. In this manner, the conversion can be carried out by performing steam methane reforming (SMR) and/or water-gas shift reactions (WGS) at high temperature, where the conversion of CO to CO 2 and H 2 is driven by the removal of H 2 to give high conversions. Methods of preparing the membrane cells and a system for use of the membrane cells to prepare hydrogen are presented. A method for sequestering CO 2 by reaction with methane or other hydrocarbon catalyzed by the novel membrane to form a syngas is also presented. |