An advanced hollow bimetallic carbide/nitrogen-doped carbon nanotube for efficient catalysis of oxygen reduction and...

Rational design and synthesis of multifunctional electrocatalysts with high-efficient activity and robust stability toward the oxygen reduction reaction (ORR), hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are highly desirable, but remain a challenging step. Herein, a novel hollow bimetallic carbide/nitrogen-doped carbon nanotube (Co₆Mo₆C₂@NCNT) is successfully synthesized through the simple pyrolysis of polypyrrole (PPy)-supported metal-organic framework (MOF) composite. Remarkable characteristics of the large surface area, hollow and porous structure, rich active sites and synergistic effect between Co₆Mo₆C₂ and NCNT arouse high catalytic efficiency. Notably, the Co₆Mo₆C₂@NCNT presents excellent ORR catalytic activity (a high half-wave potential of 0.875 V vs. reversible hydrogen electrode (RHE) and diffusion-limited current density of 6.22 mA cm^-2) via a four-electron pathway, together with outstanding stability and methanol tolerance over commercial Pt/C in 0.1 M KOH solution. The composite also exhibits superior HER performance, delivering a low overpotential of 122.14 mV at current density of 10 mA cm^-2, as well as good catalytic performance for OER in 1.0 M KOH solution. This work may provide some insight in design multifunctional electrocatalysts derived from MOF with advanced performance for sustainable energy technologies.