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-C 3 N 4 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-C 3 N 4 with efficient hydrogen evolution reaction at all pH values. In Co@N-CNT@g-C 3 N 4 , Co nanoparticles were encapsulated in the tip of carbon nanotubes and carbon nanotubes grew on g-C 3 N 4 to bridge Co particles and g-C 3 N 4. More importantly, Co particles, carbon nanotubes, and g-C 3 N 4 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 H 2 SO 4 and 1.0 M phosphate buffer saline (PBS), respectively, to drive 10 mA cm−2. Additionally, the Gibbs free energy for hydrogen adsorption (∆G H *) on the Co surface of Co@N-CNT@g-C 3 N 4 was only − 0.13 eV, which was conducive to H 2 formation. [Display omitted] • A unique coordination-polymerization integrated strategy was firstly proposed. • Co@CNT@CN showed low overpotentials (61, 145, and 170 mV) in different electrolytes. • The high capability was due to Co@carbon nanotubes and closely integrated CNT/g-C 3 N 4. • Co NPs. CNTs. g-C 3 N 4 served as H* combination. e- migration, H 2 O adsorption sites. [ABSTRACT FROM AUTHOR]