Ultrathin CoNiP@Layered Double Hydroxides Core–Shell Nanosheets Arrays for Largely Enhanced Overall Water Splitting

Electrocatalytic water splitting to give a continuous production of oxygen and hydrogen is one of goals of energy research aiming at sustainable energy demands, in which the development of bifunctional electrocatalysts toward both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) with high activity, good durability, and low cost remains a challenge. In this work, a bifunctional electrocatalyst based on transition metal phosphides CoNiP@layered double hydroxides (LDHs) core–shell nanosheets arrays for both OER and HER have been designed and synthesized. The resulting CoNiP@LDHs nanoarrays exhibit excellent electrocatalytic activity and a remarkable long-term durability (∼6 mV degradation after 500 h OER stability test). Especially, this hierarchical nanostructure needs a cell potential as low as 1.44 V at a current density of 10 mA cm –2, which is the best performance of bifunctional electrocatalysts among transition metal phosphides to our knowledge.