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?O?, 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<?<2.2; (b) SrvLawBxB?yB?zO?, 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<?<5.5).