Synergistic Ni3S2/SrMoO4/ZIF-67 ternary heterostructure as a bifunctional electrocatalyst for efficient alkaline overall water splitting

Abstract

Developing cost-effective and high-performance bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential for efficient alkaline water splitting. In this work, a ternary Ni 3 S 2 /SrMoO 4 /ZIF-67 (NSZcs) heterostructure was successfully synthesized via a facile approach and evaluated as an efficient electrocatalyst for overall water splitting. Structural and surface characterization analyses confirmed the successful formation of the integrated heterostructure with possible interfacial electronic interactions among the constituent components. Benefiting from the synergistic coupling effect and abundant electroactive sites, the NSZcs electrocatalyst exhibited excellent HER and OER activity with a low overpotential of 71 mV and 202 mV at 10 mA/cm 2 , small Tafel slopes, and high C dl with ECSA, outperforming the pristine and binary composite electrocatalysts, respectively, along with favorable reaction kinetics and good electrochemical durability. Furthermore, the two-electrode configuration of NSZcs achieved efficient overall water splitting with a low cell voltage of 1.57 V at 10 mA/cm 2 under a 1 M KOH solution. These findings demonstrate that the fabricated NSZcs heterostructure is a promising non-noble metal electrocatalyst for sustainable hydrogen production.