Zif-derived Co@hollow carbon nanofibers boost CO2 chemical fixation

Abstract

In pursuit of carbon neutrality, the development of highly efficient catalysts for the CO2 cycloaddition with epoxides represents a prominent approach of utilizing CO2 to produce valuable cyclic carbonates. Herein, Co@hollow carbon nanofibers (Co@HCNFs) catalysts with multi-level pore structures were fabricated by coaxial electrospinning, in-situ growth of zeolitic imidazolate framework-67 (ZIF-67) and subsequent high temperature pyrolysis. The hollow structure and the formation of the active sites of Co@N-doped carbon (Co@CN) were regulated by changing the feeding ratio of core to shell and the Co(NO3)2·6H2O concentration during the ZIF-67 growth, thereby fine-tuning the catalyst structures and its catalytic performance. The as-prepared Co@HCNFs-0.6–0.1 catalyst exhibits superior catalytic performance in the CO2 cycloaddition and epichlorohydrin without a co-catalyst, achieving superior specific activity of 838 mmol⋅min−1⋅g−1. The outstanding catalytic performance is attributed to its multi-level pore structures with rich N content and well-distributed Co@CN nanoparticles. Moreover, Co@HCNFs-0.6–0.1 exhibits good stability over ten reaction cycles.