Unique hybrid Ni 2 P/MoO 2 @MoS 2 nanomaterials as bifunctional non-noble-metal electro-catalysts for water splitting.

We successfully synthesized a novel electro-catalyst with a unique structure of Ni2 P nanoparticles decorating the surface of MoO2 @MoS2 sub-microwires on titanium foil (denote as NiMoO-SP/Ti) via a facile temperature-programmed sulfuration-phosphorization from its nickel molybdate precursor. The metallic MoO2 core facilitates electron transfer, and the interfaces between MoS2 nanosheets and Ni2 P nanoparticles enhance catalytic activity both for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Due to this unique structure, the obtained NiMoO-SP/Ti showed an enhanced OER performance in alkaline solution with a small Tafel slope of 85 mV dec-1 and a low overpotential of 280 and 360 mV to achieve 10 and 100 mA cm-2 in 1.0 M KOH, respectively. The catalyst also exhibited an excellent stability in 1.0 M KOH, with just 12 mV shift after electrolysis at 10 mA cm-2 for 16 h and 27 mV shift after electrolysis at 20 mA cm-2 for another 24 h. In addition, the NiMoO-SP/Ti also displayed high catalytic properties towards HER with a small Tafel slope of 77 mV dec-1 and a low overpotential of 159 mV to obtain 10 mA cm-2 in 1.0 M KOH. After electrolysis at -10 mA cm-2 for 40 h, the overpotential increased by just 25 mV, which demonstrated its high stability for HER in 1.0 M KOH. This work provides an effective route to designing a high-performance catalyst with a favorable structure for the development of electro-catalysts for water splitting.