Synergistic effect between 1D Co3S4/MoS2 heterostructures to boost the performance for alkaline overall water splitting

Abstract

The reasonable design and construction of hetero-bimetal sulfides with high performance for the oxygen/hydrogen evolution reaction (O/HER) in an alkaline electrolyte are promising but still challenging. Herein, 1D Co₃S₄/MoS₂ bimetallic sulfide nanorods (Co₃S₄/MoS₂ NRs) were prepared using MoO₃ nanorods and ZIF-67 as the precursors. As-prepared Co₃S₄/MoS₂ NRs showed excellent HER and OER activity, including low overpotentials at 10 mA cm⁻² (116 and 280 mV) and Tafel slopes (59 and 52 mV dec⁻¹). Furthermore, the density functional theory (DFT) reveals that the introduction of Co₃S₄ is conducive to reducing H₂O dissociation during the HER process. In addition, Co₃S₄ also can effectively regulate the d orbital electrons of Mo in MoS₂, which is beneficial for optimizing the H adsorption energy, thus enhancing the HER performance. Benefitting from excellent OER and HER activities, the Co₃S₄/MoS₂ NR based-electrolyzer for overall water spitting exhibits a low cell voltage of 1.66 V to reach 20 mA cm⁻² along with good stability.