In situsynthesis of NiSe@CoP core–shell nanowire arrays on nickel foam as a highly efficient and robust electrode for electrochemical hydrogen generation in both alkaline and acidic mediaElectronic supplementary information (ESI) available. See DOI: 10.1039/c7cy01606a

The efficient generation of hydrogen through the electro-splitting of water has attracted great attention. To design highly efficient and low-cost electrocatalysts for the hydrogen evolution reaction (HER) to lower the overpotential and enhance the reaction rate is of great importance for electrochemical water splitting. However, the development of low-cost and efficient electrocatalysts for the hydrogen evolution reaction is still a major challenge. In this paper, we have fabricated NiSe@CoP nanowires with a core–shell structure array grown on nickel foam (NF), denoted as NiSe@CoP NWs/NF, viaa low temperature phosphorization reaction. This 3D core–shell structure catalytic electrode provides synergistic effects, a large number of active sites, fast electron transport and enhanced electrochemical durability, resulting in a remarkable HER activity that delivers overpotentials of 91 mV and 73 mV at a current density of 10 mA cm−2in 1.0 M KOH and 0.5 M H2SO4, respectively. Notably, the NiSe@CoP NW/NF electrode shows excellent stability evaluated by 1000 potential cycles and operation with a high current density at a fixed potential for 12 h in 0.5 M H2SO4and 1.0 M KOH, respectively.