▎ 摘　　要

A novel type of hollow nitrogen-doped carbon@Bi12SiO20@nitrogen-doped graphene (H-NC@BSO@NG) nanocomposite was originally synthesized via emulsion polymerization, solvothermal process and calcination method. As a novel catalyst of cathodic oxygen reduction reaction (ORR), H-NC@BSO@NG is in detail reported for the first time. Study results have illustrated that hollow dual core-shell nanostructure with hierarchical porosity has been formed perfectly. Nitrogen-carbon layer (NC) as the hollow inner core and nitrogen-doped graphene (NG) as the outer layer can together act as both the catalysts themselves and the strong carriers of the Bi12SiO20 (BSO) catalyst, which to some extent avoid the collapse and exfoliation of the intermediate Bi12SiO20 in ORR process. And this hollow dual core-shell nanostructure can be in favor of formation of abundant bismuth-carbon/nitrogen ORR site and solve problem of poor electrical conductivity of Bi12SiO20. The H-NC@BSO@NG nanocomposite exhibits good activity, well immunity to methanol crossover, and high stability. Its onset potential can reach 1.05 V. Its limiting current density can reach 6.29 mA cm(-2) in basic electrolyte. Its relative current value can remain 91.39% of its initial value after 16000 s test. Our study perhaps inspire a novel design to synthesize hollow dual core-shell nanocomposite for the cathodic catalyst of fuel cell, air batteries, electrode nanomaterials and other purposes. (C) 2019 Elsevier Ltd. All rights reserved.