NiSe2 Nanoparticles Encapsulated in N-Doped Carbon Matrix Derived from a One-Dimensional Ni-MOF: An Efficient and Sustained Electrocatalyst for Hydrogen Evolution Reaction

The spherical-type NiSe2 nanoparticles encapsulated in a N-doped carbon (NC) matrix (NiSe2-T@NC, temperature (T) = 400-800 °C) are derived from a 1D Ni-MOF precursor of the formula [Ni(BPY)(DDE)] [(BPY = 2,2'-bipyridyl), (DDE = 4,4'-dicarboxy diphenyl ether)] via a facile solvothermal technique followed by annealing at different temperatures and selenylation strategies. The combined effect of a NC matrix and the Ni nanoparticles has been optimized during varied annealing processes with subsequent selenylation, leading to the formation of the series NiSe2-400@NC, NiSe2-500@NC, NiSe2-600@NC, NiSe2-700@NC, and NiSe2-800@NC, respectively. The variation of annealing temperature plays a vital role in optimizing the catalytic behavior of the NiSe2-T@NCs. Among different high-temperature annealed products, NiSe2-600@NC shows superior electrocatalytic performance because of the unique spherical-type morphology and higher specific surface area (57.95 m2 g-1) that provides a large number of electrochemical active sites. The synthesized material exhibits a lower overpotential of 196 mV to deliver 10 mA cm-2 current density, a small Tafel slope of 45 mV dec-1 for better surface kinetics, and outstanding durability in an acidic solution, respectively. Consequently, the post stability study of the used electrocatalyst gives insight into surface phase analysis. Therefore, we presume that the synthesized 1D MOF precursor derived NiSe2 nanoparticles encapsulated in a NC matrix has excellent potential to replace the noble-metal-based electrocatalyst for enhanced hydrogen evolution through simple water electrolysis.