Thermal method for fabricating a hydrogen separation membrane on a porous substrate

A method of making a hydrogen permeable composition, comprising

• forming a mixture of metal oxide powder and ceramic oxide powder and optionally a pore former,
• pressing the mixture to form an article,
• pre-sintering the article at about 700° C. in air to remove at least some of the pore former if present and to impart mechanical integrity and porosity to the article, and thereafter providing a dense hydrogen permeable portion near the surface of the sintered mixture and a porous core having a lower density relative to the dense surface layer by sintering the article in a reducing atmosphere comprising hydrogen to reduce metal oxide near the surface of the article to a metal and leave metal oxide in the core of the article,
• the dense hydrogen permeable portion having a higher initial concentration of metal than the remainder of the sintered mixture,
• the metal oxide being selected from the oxides of Ni, Pd, Pd alloys, Nb, Ta, Zr, V or mixtures thereof,
• the ceramic oxide being selected from yttria stabilized zirconia, shrinkable alumina, Y or Gd doped cerates, titanates, zirconates of barium or strontium or mixtures thereof,
• wherein the dense hydrogen permeable portion has a metal concentration in the range of from about 20 to about 80 percent by volume.