Multiphase Fe-doped Ni3S2/MoOx electrocatalyst prepared by facile one-step hydrothermal for full-cell water splitting: Effect of Mo on physical and electrochemical properties

Herein, we develop a multiphase strategy to improve the HER performance by incorporating the MoOx phase with the addition of MoCl5 during the one-step hydrothermal. Adding MoCl5 at 0.5 mmol (MFN-0.5) yields the best HER performance, with an overpotential of 261 mV at a current density of 100 mA/cm2. The MFN-0.5 catalyst exhibits excellent performance for both HER and OER, enabling it to drive full-cell water splitting with cell potentials of 1.50 and 1.71 V at 10 and 100 mA/cm2, respectively. We further scale up the MFN-0.5 (4 ×4 cm2) for a single stack-cell electrolyzer, requiring a cell potential of 1.85 V to achieve a large current density of 250 mA/cm2. Incorporating the MoOx phase accelerates the water dissociation step and protects the metal sulfide surface from oxidation under anodization in an alkaline environment. Our findings offer a promising approach for developing highly efficient catalysts for electrolytic water-splitting applications. [Display omitted] •A multiphase strategy is developed to improve the HER performance by facile one-step hydrothermal method.•The incorporation of MoOx into Fe-Ni3S2 significantly improves HER and overall water splitting performance.•The best MNF-0.5 catalyst only needs cell potentials of 1.50 at 10 mA/cm2 and 1.71 V at 100 mA/cm2.•The scale up MFN-0.5–4 ×4 cm2 single stack cell requires a cell potential of 1.85 V at 250 mA/cm2.•MoOx accelerates water dissociation step and protects metal sulfide surface from oxidation.