| abstract |
Processes are disclosure which comprise alternately contacting an oxygen-carrying catalyst with a reducing substance, or a lower partial pressure of an oxidizing gas, and then with the oxidizing gas or a higher partial pressure of the oxidizing gas, whereby the catalyst is alternately reduced and then regenerated to an oxygenated state. In certain embodiments, the oxygen-carrying catalyst comprises at least one metal oxide-containing material containing a composition having one of the following formulas: (a) CexByB'zB''Od, wherein B = Ba, Sr, Ca, or Zr; B' = Mn, Co, or Fe; B''= Cu; 0.01< x <0.99; 0< y <0.6; 0< z <0.5; and 1 < d <2.2; (b) SrvLawBxB'yB''zOd, wherein B = Co or Fe; B' = Al or Ga; B'' = Cu; 0.01< v <1.4; 0.1< w <1.6; 0.1< x <1.9; 0.1< y <0.9; 0< z <2.2; and 3< d <5.5). |