Morphology Driven Enhancement in Ternary Transition Metal Sulfides for Oxygen Evolution Reaction

Oxygen evolution reaction (OER) is an important half‐reaction in water splitting for sustainable hydrogen generation, yet overcoming its sluggish kinetics remains a significant challenge. The spinel structure of ternary transition metal sulfides (TTSs) has gained lots of attention due to their noteworthy electrochemical properties, such as electrical conductivity, surface flexibility, thermal stability, and catalytic activity. The morphologies of nanostructures are critically important for several reasons, as they directly influence the physical, chemical, mechanical, and catalytic properties of the material. Even though the spinel structure intrinsically has a unique framework and specific arrangement of metal ions, which enhances the catalytic performance. This review focuses on the morphology and electrocatalytic activity of recently reported TTS electrocatalysts for OER. Two‐dimensional materials resulted in excellent OER performance due to their improved surface area and catalytically active sites. For example, a recent study reported that the NiCo 2 S 4 /ZnS nanosheets exhibited a low overpotential of 140 mV at 10 mA cm −2 with a small Tafel slope of 47 mV dec −1 , highlighting their potential for efficient and stable OER applications. In addition, the heterostructure TTS composite shows greater catalytic activity because it produces interfaces to enhance the OER efficiency. This review summarizes the correlation between morphology and catalytic activity of spinel compounds, giving insight to elucidate strategies for the development of high‐performance catalysts for OER.