▎ 摘　　要

Synthesized large porous Fe3O4 microspheres of about similar to 500 nm located on graphene oxide (GO) could evolve into much smaller iron carbide nanocapsules of about similar to 10 nm, which exhibit excellent performance for the production of alpha-olefins. The formation of small iron carbide nanocapsules is driven by the growth of carbon nanofibers (CNFs) to induce stress over the large Fe3O4 microspheres.