Carbon nanofibers with hierarchical structure were synthesized by combining Co-containing zeolitic imidazolate frameworks (ZIF-67) with natural eggshell membranes (ESMs). Benefiting from the hierarchical structure and element modification of Co/N, the obtained nanofibers exhibited excellent oxygen reduction reaction (ORR) performance. The reusing of ESMs trash made this strategy meaningful for environment. (C) 2019 Elsevier Inc. All rights reserved.