Abstract:

Transition metal sulfides (TMSs) are widely recognized as promising catalysts for the oxygen evolution reaction (OER), yet their large-scale application is hindered by poor conductivity, severe aggregation and sluggish reaction kinetics. To address these issues, a ternary CoS₂/FeS₂/Ti₃C₂T_x hybrid is rationally constructed via a three-in-one strategy, which simultaneously achieves the support introduction, morphology modulation and heterojunction construction. Structural characterizations reveal a hierarchical architecture composed of 1D CoS₂ nanorods, 0D FeS₂ nanoparticles and 2D conductive Ti₃C₂T_x nanosheets, wherein CoS₂ and FeS₂ form a distinctive 1D/0D heterojunction. Density functional theory calculations demonstrate that strong electronic coupling at the CoS₂/FeS₂ heterointerface accelerates electron transfer and optimizes the adsorption behavior of oxygen intermediates. Benefiting from the synergistic effects between the CoS₂/FeS₂ heterojunction and the conductive Ti₃C₂T_x support, the as-prepared CoS₂/FeS₂/Ti₃C₂T_x hybrid exhibits elevated conductivity, promoted dispersibility and accelerated reaction kinetics, thus resulting in markedly improved OER performance as compared to the control samples. Additionally, the CoS₂/FeS₂/Ti₃C₂T_x hybrid presents a remarkably low overpotential of 284 mV when used as the anode catalyst in a water-splitting device, demonstrating its outstanding applicability for overall water electrolysis. Overall, this work provides a viable strategy for engineering high-performance TMS-based electrocatalysts through heterointerface design and conductive support integration.

Key words: Transition metal sulfides, CoS₂/FeS₂/Ti₃C₂T_x, 1D/0D heterojunction, Oxygen evolution reaction, Water-splitting devices