Highly stable hierarchical core-shell structure CuMn0.5Co2O4@CC with self-regulating electronic and conductivity for its improved OER performance

Abstract

Improving the catalytic activity and long-term stability of catalysts have always been the goal of its application. The structure stability and good electrical conductivity of catalysts are the key to OER performance, which have been challenge for application of catalysts. In the paper, we designed an in-situ growth of hierarchical core-shell structure CuMn0.5Co2O4@CC with superior conductivity directly as the catalytic electrode for improved OER performance. The well-standing CuMn0.5Co2O4 nanoneedles with mesoporous structure entirely encapsulated on the carbon fibers, exposing a large special surface area and structural stability, while carbon fibers improved its electrical conductivity. Meanwhile, the richer oxygen vacancies and self-regulating electronic structure by the diversification of the metal oxidation state in the catalyst would promote the OER activity and stability. Benefitting from these merits, the requiring overpotential of CuMn0.5Co2O4@CC was 189 mV at the current density of 10 mA cm−2 and the Tafel slop value was 64.1 mV⋅dec−1, which was lower than that of CuMn0.5Co2O4//CC (η10 = 337 mV and Tafel slop value of 113.9 mV⋅dec−1). In addition, the CuMn0.5Co2O4@CC had a competitive stability of with the current retention rate of 95.3 % after 1000 cycles. The present work provide a useful attempt to construct highly catalytic active and durably stable metal oxide composite catalysts.