La0.8Sr0.2Mn0.8Co0.2O3-δ perovskite as an efficient functional electrocatalyst for oxygen reduction reactions

The negative effects of the widespread and rough use of fossil energy have promoted the emergence of new energy technologies. Cost-effective electrocatalysts play an irreplaceable role in energy conversion and storage, especially oxygen reduction reactions (ORR) catalysts. While the reserves of precious metal catalysts are rare and expensive, it is of prime importance to develop catalysts that can replace precious metals. In the present work, La0.8Sr0.2Mn0.8Co0.2O3-δ (LSMC) with Mn and Co is successfully prepared by sol-gel method and subsequent calcination. The characterizations of physical phase, microstructure, BET and valence state of elements demonstrate that LSMC material possesses ample mesoporous structure, large specific surface area, and multivalent elements, which can provide abundant active sites for ORR. The electrochemical tests reveal that the LSMC delivers outstandingly higher electrocatalytic activity for ORR, relatively lower overpotential and Tafel slope and a better long-term stability than the other perovskites (LSM, LSC) under alkaline condition. Furthermore, the coupling effects of high content of high-valence Co, multivalent Mn and large amounts of adsorbed oxygen endow the catalyst excellent ORR electrocatalytic activity. The present work investigating the effect of Mn and Co elements on the electrocatalysis of LSMC perovskite, will provide the possibility of developing a new type of perovskite electrocatalyst with excellent ORR electrocatalytic activity and low cost.