NiSe2/Ni5P4 Nanosheets on Nitrogen-doped Carbon Nano-fibred Skeleton for Efficient Overall Water Splitting

Abstract 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.