Metal organic framework nanofibers derived Co3O4-doped carbon-nitrogen nanosheet arrays for high efficiency electrocatalytic oxygen evolution

Abstract

Despite significant advances in preparing functional carbon and transition metal oxide (TMO) nanomaterials arising from metal–organic frameworks (MOFs), the TMO nanoparticles (NPs) incorporated on 2D carbon-nitrogen nanosheet arrays constructed from MOF structure have not been explored before. Herein, a facile self-assembly methodology for MOF nanofibers derived Co3O4 NPs doped carbon-nitrogen nanosheet arrays anchored on Ni foam (Co3O4@C-N NSA/NiF) is reported. Co(II)-MOF nanofiber arrays are electrodeposited directly on Ni foam at room-temperature. Then after pyrolysis at 300 °C for 2 h in air, the periodic arrangement of metal Co(II) ion nodes and nitrogen-rich organic moieties in the Co(II)-MOF scaffolds are successfully converted into carbon-nitrogen nanosheet arrays imbeded small Co3O4 NPs. Co3O4@C-N NSA/NiF directly as binder-free electrode for oxygen evolution reaction (OER) catalyst, only needs low overpotentials of 245 mV to drive catalytic current densities of 25 mA cm−2 in 1.0 M KOH, which is superior to other MOF-derived catalysts. Co3O4@C-N NSA/NiF also demonstrates low resistance, outstanding durability with a high turn-over frequency of 0.958 s−1 at an overpotential of 370 mV. The enhanced OER performance arises from that Co3O4 NPs uniformly anchored on sp2-hybridized carbon-nitrogen nanosheet array brings about more active sites, boosting mass transport and electron transfer.