Heterostructured Arrays of Ni_xP/S/Se Nanosheets on Co_xP/S/Se Nanowires for Efficient Hydrogen Evolution

The development of efficient electrocatalysts for hydrogen evolution reaction (HER) is of increasing importance in energy conversion schemes. The earth-abundant transition-metal phosphides, especially CoP and Ni₂P, have emerged as promising catalysts for HER. We describe here the preparation and characterization of a hybrid catalyst of Ni₂P nanosheets@CoP nanowires on a carbon cloth for the reaction. The heterostructure and synergistic effects of the Ni₂P and CoP components result in an extremely low overpotential of 55 mV for achieving a catalytic current density of 10 mA cm^-2, which is remarkable for transition-metal phosphide electrocatalysts. The synthetic procedure could be readily extended to related, heterostructured bimetallic sulfides or selenides for HER.