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

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 N-C 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 Ndoped 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.

Automated summary

In this study, nitrogen-doped carbon nanotubes (N-doped CNTs) derived from dicyandiamide pyrolysis were introduced into MOF-derived CoFe alloy and fluoride catalysts, resulting in significantly improved performance for oxygen evolution reaction (OER). The introduction of N-doped CNTs formed a structure of interconnected carbon nanotube active sites, which prevented active site agglomeration and improved catalytic conductivity, leading to enhanced mass transfer and active site exposure. This research made novel contributions to boosting catalytic ability of MOF-derived catalysts in OER catalysis.