ZnCoNiS nanoflowers electrodes with rich heterointerface as efficient bifunctional electrocatalyst for overall water splitting

Constructing heterojunction nanocomposites is promising for overall water splitting. Herein, the metal-organic frameworks (MOFs) derived multiphasic transition metal sulfide nanoflowers heterostructure electrode (ZnCoNiS) was synthesized by the hydrothermal and sulfuration methods. The nanoflowers structure can provide a large electrochemical active surface area and the abundant heterogeneous interfaces are beneficial to increase the synergy between different components to improve the kinetic energy of the reaction. The obtained ZnCoNiS shows outstanding electrocatalytic performance with low overpotentials of 134 mV for the oxygen evolution reaction (OER) and 146 mV for hydrogen evolution reaction (HER) at 10 mA cm−2. Impressively, the ZnCoNiS catalyst exhibits remarkable overall water-splitting performances with a cell voltage of 1.52 V at 10 mA cm−2 and excellent stability in catalysis for over 100 h. This study demonstrates an approach for the design of rich heterogeneous junctions with high activity and stability, which can be used in the fields of solar energy to drive water splitting for hydrogen production.