CoCuSe/Cu_2-xSe Heterojunction Modified High Electronic Conductivity Porous Carbon Nanofibers as Bifunctional...

Developing efficient, stable, low-cost bifunctional ORR/OER electrocatalysts remains challenging. Methods such as morphological design, element doping and interface engineering are common and effective strategies to effectively improve oxygen electrocatalytic activity. On this basis, we designed and prepared the transition metal selenide heterojunction supported conductive hierarchical porous carbon nanofibers electrocatalyst (CoCuSe/Cu_2-xSe@PCNFs). The obtained Cu_2-xSe exhibits well electronic conductivity, and bimetallic selenides also can enhance the dispersion and stability of active sites, thus greatly improving ORR and OER activities. The theoretical calculations also indicate that a novel interface can be formed between the two components in the heterojunction, and an internal electric field also is generated at the interfaces. The result can effectively adjust the electron distribution of the active material, optimize the adsorption and desorption of reaction intermediates and subsequently enhance the catalytic performance. Benefiting from the synergistic effect between components and unique morphological structure, the CoCuSe/Cu_2-xSe@PCNFs exhibits excellent bifunctional activity for oxygen reduction reaction (ORR) (E_1/2 = 0.85 V) and oxygen evolution reaction (OER) (E_{j = 10} = 300 mV) in alkaline electrolyte, and demonstrates superior stability (>1000 h) for high-performance zinc-air batteries. This study combines experiment and theory to provide a new approach for exploring multifunctional electrocatalysts.