Mesoporous and dual-shelled hollow CeO2@CoNC nanospheres as efficient and stable oxygen reduction reaction electrocatalysts.

The electrocatalytic oxygen reduction reaction (ORR) is the key bottleneck of fuel cells and rechargeable metal-air batteries, and recently, metal nitrogen complex carbon (M N C) demonstrates great potential in these fields. However, the complex and easily degraded M N C structure often results in inferior activity and poor durability in electrolysis. Herein, we fabricate a catalyst of h-CeO 2 @CoNC through the extended Stöber method and subsequent pyrolysis, involving the hollow CeO 2 as the core and Co N C as the shell. The h-CeO 2 @CoNC catalyst exhibits notable ORR catalytic performances in 0.1 M KOH with a half-wave potential of 0.82 V and excellent durability, attributed to the synergistic interaction between CeO 2 and Co N C matrix. Specifically, the inner layer of CeO 2 is principally responsible for enhancing the chemical stability and the outer one of Co N C matrix is beneficial to boosting the ORR catalytic activity. This work provides an efficient preparation approach and further insight of rational design of the unique M N C catalysts for energy storage. [ABSTRACT FROM AUTHOR]