Improvement of the catalytic properties of porous lanthanum manganite for the oxygen reduction reaction by partial substitution of strontium for lanthanum

Partial substitution of lanthanum with strontium yields lanthanum strontium manganite (La1-xSrxMnO3, 0 < x < 1). In this work, lanthanum strontium manganite catalysts with x = 0, 0.2, 0.4, 0.6 and 0.8 are synthesized and characterized, and their catalytic properties for the oxygen reduction reaction (ORR) are studied both experimentally and theoretically. It is found that the catalyst with x = 0.6 (La0.4Sr0.6MnO3) displays the highest ORR activity. To further improve the catalytic performance of this catalyst, porous La0.4Sr0.6MnO3 is prepared using carbon spheres as pore-forming templates. The results show that use of a moderate amount of carbon spheres helps to improve the ORR activity.