Synergistic effect: Hierarchical Ni3S2@Co(OH)2 heterostructure as efficient bifunctional electrocatalyst for overall water splitting

Non-noble metal catalysts with high-performance are intensively exploited toward water electrolysis. Herein, we fabricate a novel Ni3S2@Co(OH)2 heterostructure with a tentative method combining hydrothermal method with electrodeposition, in which the Ni3S2 nanosheets are evenly integrated with Co(OH)2 nanoparticles. Electrochemical tests reveal preeminent catalytic activities and durability on this heterostructure for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). It presents high catalytic activities of 110 and 257 mV at 10 mA cm−2 for HER and OER, respectively, in 1.0 M KOH solution. Moreover this bifunctional electrode requires only 1.61 V to reach 10 mA cm−2 and shows excellent durability when assembled as an electrolyzer, superior than that of Pt-C||IrO2. The promoted activities are benefited from the interfacial cooperation and synergistic effect between Ni3S2 and Co(OH)2, because of which the charge-transfer ability is enhanced and surface reactivity is of furtherance. This work is of very profound significance on electrocatalysts for water splitting, specific performances: (1) This heterostructure is synthesized based on interface engineering. (2) The promoted performance is due to the synergistic effect of two onefold-components. (3) The catalysis activities for HER and OER can synchronously reach ideal states when it is used as bifunctional catalyst.