Anchoring SnS nanoflakes on CuCo2O4 acicular sprouts for overall water splitting

Abstract

Employing a bifunctional electrocatalyst capable of simultaneously performing Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER) under the same conditions of temperature, pressure, and pH is beneficial for realizing compact and efficient electrolyzers. In the pursuit of cultivating the superior abilities of ternary transition metal oxides and sulphides in OER and HER, an Argyrophylla-like heterostructure electrode consisting of Copper Cobalt Oxide (CuCo2O4) and Tin Sulfide (SnS) have been fabricated through a facile two-pot hydrothermal method. The surface level morphology and electrochemical active sites of binder-free SnS/CuCo2O4/NF heterostructure bifunctional catalyst were modified to achieve lower overpotentials for both OER (315 mV @ 20 mA/cm2) and HER (98 mV @ 20 mA/cm2) in 1.0 M KOH electrolyte medium. The proclaimed efficiencies are attributed to the enhanced oxygen vacancies, interfacial bonds and surface sulfur sites in the heterostructure as evident from electrochemical and X-ray photoelectron spectroscopy (XPS) studies. Apart from that, the proposed heterostructure electrode attained a current density of 10 mA/cm2 with a very low cell voltage of 1.60 V when employed as a dual electrode in an electrolyser cell. The Sn–O bond at the interface of CuCo2O4 and SnS stabilizes the heterostructure that helped in maintaining the lower current degradation rate (CDR) in Chronoamperometry (CA) test.