Despite being technically possible,
the hydrogen production by means of electrocatalytic water splitting
is still practically unreachable mainly because of the lack of inexpensive
and high active catalysts. Herein, a novel and facile approach by
melamine polymerization, exfoliation and Co<sup>2+</sup>-assisted
thermal annealing is developed to fabricate Co nanoparticles embedded
in bamboo-like and nitrogen-rich carbonitride nanotubes (Co@NCN).
The electronic interaction between the embedded Co nanoparticles and
N-rich carbonitride nanotubes could strongly promote the HER performance.
The optimized Co@NCN-800 exhibits outstanding HER activity with an
onset potential of −89 mV (vs RHE), a large exchange current
density of 62.2 μA cm<sup>–2</sup>, and small Tafel slope
of 82 mV dec<sup>–1</sup>, as well as excellent stability (5000
cycles) in acid media, demonstrating the potential for the replacement
of Pt-based catalysts. Control experiments reveal that the superior
performance should be ascribed to the synergistic effects between
embedded Co nanoparticles and N-rich carbonitride nanotubes, which
originate from the high pyridinic N content, fast charge transfer
rate from Co particles to electrodes via electronic coupling, and
porous and bamboo-like carbonitride nanotubes for more active sites
in HER