Multicomponent Co9S8@MoS2 nanohybrids as a novel trifunctional electrocatalyst for efficient methanol electrooxidation and overall water splitting

In view of the importance of multifunctional catalysts that can drive different electrocatalytic reactions in the same electrolyte solution, we designed and prepared a series of multicomponent nanohybrids composed of Co9S8 and MoS2 derived from cobalt-doped polyoxometalate (Co-POMs) by one-pot calcination method. The obtained Co9S8@MoS2 nanohybrids were composed of Co9S8, MoS2, Co-Mo-S phases and assembled nanosheets, and therefore were explored as trifunctional electrocatalysts for hydrogen evolution reaction, oxygen evolution reaction, and methanol oxidation reaction (MOR) in an alkaline medium. The nanostructure and chemical components of the series of Co9S8@MoS2 nanohybrids can be modulated by changing the mole ratios of H5Mo12O41P to Co(NO3)2 precursor. Compared with the sole component and other reported Co9S8@MoS2 nanohybrids, the Co9S8@MoS2 nanohybrid prepared from the 1:1 ratio of PMo12 and Co(NO3)2 exhibited superior MOR catalysis efficiency (121.4 mA cm−2) and an extremely low overpotential (1.49 V) for overall water splitting at a current density of 10 mA cm−2 owning to the effective synergism among Co9S8, MoS2, and Co-Mo-S phase. Overall, this study provides a feasible approach to developing efficient and stable trifunctional bimetal electrocatalysts for clean-energy applications.