High polarity catalyst of CoFe alloy/fluoride interconnected by bamboo-like nitrogen-doped carbon nanotubes for efficient oxygen evolution reaction

[Display omitted] •High polarity catalyst interconnected by nitrogen-doped carbon nanotubes for efficient oxygen evolution reaction.•The problems of agglomeration and low conductivity were improved by forming the speical structure.•Low overpotentials of 231 mV to drive 10 mA cm−2 when loaded on the glassy carbon electrode.•High activity form easy active phase formation and synergism between Fe and Co species.•Conductivity improvement by N-doped carbon nanotubes derived from dicyandiamide with high graphitic N. The easy agglomeration and low conductivity of high polarity catalysts restrict the active phase formation for oxygen evolution reaction (OER) in water-splitting reactions, even for the catalysts with conductive NC species derived from MOFs carbonization. Herein, as a proof of concept, the bamboo-like nitrogen-doped carbon nanotube (N-doped CNT) from dicyandiamide pyrolysis was introduced into MOFs-derived high polarity catalyst of CoFe alloy and fluoride, and the performance for OER can be largely improved to low overpotentials of 231 mV to drive 10 mA cm−2 when loaded on the glassy carbon electrode. The structural evolution induced by the N-doped CNT introduction was carefully studied by both spectroscopic analysis and electrochemical measurements, and it was revealed that forming the structure of carbon nanotube interconnected active sites prevented the active site agglomeration and improved the catalytic conductivity, which improved the mass transfer, and active site exposure. The largely improved performance was attributed to the easy active phase formation by high polarity metal fluoride, the synergy between Fe and Co species, and conductivity improvement by N-doped carbon nanotubes derived from dicyandiamide with high graphitic N. The current work showed some novel contributions to catalytic ability boosting for MOF-derived catalysts in OER catalysis.