Ni-Doped Co3S4 Hollow Nanobox for the Hydrogen Evolution Reaction

Metal–organic framework (MOF)-derived Co3S4 nanostructures are prepared by selective Ni-doping via a two-step treatment including coprecipitation and ion exchange. First, Ni2+ is introduced into bimetallic MOFs and then selectively doped into the tetrahedral sites in Co3S4 through hydrothermal treatment. The bimetallic MOFs are transformed into hollow nanobox by the Kirkendall effect. The selective doping of Ni2+ can affect the structure situation of Co2+, which is related to the formation of Co–S bonding. Benefiting from the selective Ni doping, the free energy of H intermediates adsorption and the conductivity are optimized. Meanwhile, the Ni doping and the unique hollow nanostructure endow Ni–Co3S4 composites with abundant active sites for the hydrogen evolution reaction (HER). The Ni–Co3S4 boxes significantly ameliorate the HER activity of Co3S4 in the acidic and alkaline solutions. It is just needed to afford the overpotential of 224 mV in acid and 262 mV in alkaline to achieve a current density of 10 mA cm–2 without iR correction.