Heterostructured Arrays of NixP/S/Se Nanosheets on CoxP/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.