Preparation of cobalt-based nanomaterials carried by nitrogen-doped carbon nanotubes as high performance electrocatalysts for hydrogen evolution reaction

Among transition metal phosphides, CoNiP was considered to be the most promising electrocatalyst for hydrogen evolution reaction (HER) to replace the precious metal platinum for its excellent catalytic performance and durability. In this work, an approach combining impregnation with calcination and phosphorization was used to prepare highly dispersed CoNiP nanoparticles on nitrogen-doped carbon nanotubes (NCNTs). The CoNiP/NCNTs catalysts exhibited the advantages of low overpotential and high durability. The content of sodium hypophosphite as phosphorization agent was a crucial factor to affect the performance of the catalysts. The optimized CoNiP/NCNTs with an appropriate content of sodium hypophosphite exhibited best performance with an onset-overpotential of 44 mV and a overpotential of 75 mV at a current density of 10 mA cm−2 in 0.5M H2SO4. After the chronopotentiometry measurement for 24h, the overpotential presented a decrease of only 6 mV, indicating its excellent durability.