Preparation of CoNiP nanoparticles supported on nitrogen-doped carbon nanotubes as high performance electrocatalysts for the hydrogen evolution reaction

CoNiP nanoparticles dispersed on nitrogen. doped carbon nanotubes (NCNTs) as electrocatalysts for the hydrogen evolution reaction were prepared by impregnating the NCNTs with a solution containing Ni(NO3)(2)center dot 6H(2) O and Co(NO3) 2 center dot 6H2 O, followed by calcination at 500 degrees C for 2h and phosphorization at 350 degrees C for 2 h in a furnace with a crucible of sodium hypophosphite upstream of the CoNiO2/NCNT that served as the phosphorization agent. Results indicated that the CoNiP/NCNT catalysts had the advantages of low overpotential and high durability. The sodium hypophosphite content was a crucial factor affecting the performance of the catalysts. The optimized CoNiP/NCNT catalyst with an appropriate content of the phosphorization agent (0. 2 g sodium hypophosphite/0. 02 g CoNiO2/NCNT) exhibited the best performance with an onset-overpotential of 44 mV and an overpotential of 75 mV at a current density of 10 mA cm(-2) in 0.5 M H2SO4. After the chronopotentiometry measurement for 24 h, the overpotential showed a decrease of only 6 mV, indicating its excellent durability.