Fe/Fe<sub>3</sub>C-NC Nanosheet/Carbon Nanotube Composite Electrocatalysts for Oxygen Reduction Reaction
Shichuan Su, Long Huang, Shan Su, Chunfeng Meng, Hu Zhou, Liuting Zhang, Ting Bian, Aihua Yuan
Abstract
The construction of active and durable electrocatalysts based on a high abundance of elements toward oxygen reduction reaction (ORR) is critical for proton-exchange membrane fuel cells and metal–air batteries. Here, a composite nanostructure composed of Fe/Fe3C-NC nanosheets and carbon nanotubes (G-Fe/Fe3C-NC/CNTs) was designed by simply annealing a glucose-chelated Fe-coordinated metal–organic frameworks. The introduction of glucose can not only effectively prevent the collapse of the initial two-dimensional (2D) leaflike zeolitic imidazolate frameworks (ZIFs) during the carbonization process but also boost the growth of carbon nanotubes (CNTs). Benefiting from efficient Fe/Fe3C and Fe–Nx moieties, high specific surface area, and electron-conducting highways provided by the unique composite structure, the obtained G-Fe/Fe3C-NC/CNTs electrocatalysts achieved an impressive ORR activity with a higher positive onset potential of 1.02 V and half-wave potential of 0.87 V over the commercial Pt/C. Significantly, it also exhibits outstanding stability after 6000 cyclic voltammogram (CV) cycles with nearly negligible decay in half-wave potential, which makes it one of the promising Pt-free catalysts for ORR.