Hierarchical heterostructure CoCO3@NiFe LDH nanowires array as outstanding bifunctional electrocatalysts for overall water splitting

Abstract

Hierarchical heterostructure CoCO3@NiFe layered double hydroxide (LDH) was composed of NiFe LDH nanosheets and CoCO3 nanowire arrays. Because of the advantage of the hierarchical structure, the as-prepared catalyst reveals excellent catalytic performance in oxygen evolution reaction (OER) with overpotential of 232 mV at a current density of 20 mA cm−2. It also performs well in hydrogen evolution reaction (HER), which only needs overpotential of 171 mV to reach a current density of 10 mA cm−2. Furthermore, heterostructure CoCO3@NiFe LDH is used for overall water splitting, the voltage required at 10 mA cm−2 is only 1.67 V. The performance of the CoCO3@NiFe LDH showed little degradation in the 20 h stability test.