One-pot solvothermal synthesis of Co2P nanoparticles: An efficient HER and OER electrocatalysts

Development of an inexpensive electrocatalyst for hydrogen evolution (HER) and oxygen evolution reactions (OER) receives much traction recently. Herein, we report a facile onepot ethyleneglycol (EG) mediated solvothermal synthesis of orthorhombic Co2P with particle size similar to 20-30 nm as an efficient HER and OER catalysts. Synthesis parameters like various solvents, temperatures, precursors ratios, and reaction time influences the formation of phase pure Co2P. Investigation of Co2P as an electrocatalyst for HER in acidic (0.5 M H2SO4) and alkaline medium (1.0 M KOH), furnishes low overpotential of 178 mV and 190 mV, respectively to achieve a 10mA cm similar to 2 current density with a long term stability and durability. As an OER catalyst in 1.0 M KOH, Co2P shows an overpotential of 364 mV at 10 mA cm(-2) current density. Investigation of Co2P NP by XPS analysis after OER stability test under alkaline medium confirms the formation of amorphous cobalt oxyhydroxide (CoOOH) as an intermediate during OER process. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

A facile one-pot ethyleneglycol-mediated solvothermal synthesis of orthorhombic Co2P with particle size around 20-30 nm was reported as an efficient catalyst for both HER and OER. Co2P showed low overpotentials and long-term stability in acidic and alkaline medium for HER, as well as an overpotential of 364 mV at 10 mA cm(-2) current density for OER. XPS analysis confirmed the formation of amorphous cobalt oxyhydroxide (CoOOH) as an intermediate during the OER process.