Thermogravimetric reduction of lanthanum strontium iron perovskite oxides with carbon monoxide

The reduction behaviour from surface to bulk of lanthanum strontium iron perovskite oxide (La 1− x Sr x FeO 3 :0 ⩽ x ⩽ 1.0) particles by CO gas was studied by means of TG, DSC, IR, XRD and X-ray micro-analysis. Interactions with CO and oxygen species that proceed exothermally gave a large weight loss and weight increase respectively. Both increased with the increase of x in La 1− x Sr x FeO 3 . A weight loss was observed in the temperature range 525–725 K as a result of the desorption and reduction by CO of surface oxygen species. A weight increase was observed in the temperature range 775–1125 K as a result of the formation of carbon and/or carbonaceous species. It was concluded that the disproportionation of CO occurs at higher x and higher temperature.