NiSe₂/Ni₅P₄ nanosheets on nitrogen-doped carbon nano-fibred skeleton for efficient overall water splitting

Combining a variety of factors to optimize the performances of electrocatalysts has become a new breakthrough for the development of low-cost electrolytic catalysts. In this work, we constructed N-doped carbon fibers as the substrate, which could provide high electronic conductivity and large surface area for the load of active catalysts, as well as close incorporation. The nanosheets morphology of NiSe₂/Ni₅P₄ is conducive to enlarging the specific surface area and exposing more active sites. The electrical conductivity is improved by the selenide and carbon nano-fiber substrate. The multiple features, including the unique structure characteristics, heterostructure of NiSe₂ and Ni₅P₄, and high electroconductivity, endow NiSe₂/Ni₅P₄ with superior catalytic activity towards water splitting. As a result, the overpotentials at the cathode current density of 10 and 100 mA cm⁻² upon NiSe₂/Ni₅P₄ nanosheets are 112 and 350 mV in 0.5 M H₂SO₄. For oxygen evolution reaction (OER), the overpotential of NiSe₂/Ni₅P₄ nanosheets at a current density of 10 mA cm⁻² in alkaline electrolyte is 316 mV. Furthermore, the bifunctional NiSe₂/Ni₅P₄ nanosheets exhibit excellent working stability for both HER, OER and overall water splitting, showing potential application in hydrogen energy.