Immobilization of Co nanoparticles into N-doped carbon nanotube on g-C3N4 via coordination-polymerization integrated strategy for efficient H2 evolution reaction at all pH values

Constructing Co-based carbon nanotubes/g-C3N4 structure via integrated strategy remains a challenge in cobalt-based electrocatalysis. We firstly proposed a coordination-polymerization integrated strategy for the preparation of Co@N-CNT@g-C3N4 with efficient hydrogen evolution reaction at all pH values. In Co@N-CNT@g-C3N4, Co nanoparticles were encapsulated in the tip of carbon nanotubes and carbon nanotubes grew on g-C3N4 to bridge Co particles and g-C3N4. More importantly, Co particles, carbon nanotubes, and g-C3N4 were assembled simultaneously skillfully to construct a closely integrated interface, thereby enhancing electron transfer efficiency. Electrochemical tests showed that the structure has high catalytic activity, with overpotentials of 61, 145, and 170 mV in 1 M KOH, 0.5 M H2SO4 and 1.0 M phosphate buffer saline (PBS), respectively, to drive 10 mA cm-2. Additionally, the Gibbs free energy for hydrogen adsorption (∆GH⁎) on the Co surface of Co@N-CNT@g-C3N4 was only -0.13 eV, which was conducive to H2 formation.