SOLID STATE OXYGEN ANION AND ELECTRON MEDIATING MEMBRANE AND CATALYTIC MEMBRANE REACTORS CONTAINING THEM

摘要

This invention provides solid state gas-impermeable, ceramic membranes usefulfor promotion of oxidation-reduction reactions and for oxygen gas separation.Membranes of this invention are fabricated from a single-component materialwhich exhibits both electron and oxygen-anion conductivity. The electron- andoxygen-anion-conducting materials of this invention are compounds having abrownmillerite structure which have the general formula A2B2O5, where A and Bmost generally can be any metal. Specifically, membrane materials of thisinvention are single-phase brownmillerite materials having the stoichiometricformula: A2-xA'xB2-yB'yO5+z where A is an alkaline earth metal ion or mixtureof alkaline earth metal ions; A' is a metal ion or mixture of metal ions wherethe metal is selected from the group consisting of metals of the lanthanideseries and yttrium; B is a metal ion or mixture of metal ions wherein themetal is selected from the group consisting of 3d transition metals, and thegroup 13 metals; B' is a metal ion or mixture of metal ions where the metal isselected from the group consisting of the 3d transition metals, the group 13metals, the lanthanides and yttrium; x and y are, independently of each other,numbers greater than zero and less than 2; and z is a number that renders thecompound charge neutral.