Trimetallic Zn-Co-Ni Selenide Nanoparticles as Electrocatalysts for the Hydrogen Evolution Reaction

The evaluation and establishment of extremely efficient non-noble metal-based electrocatalysts for the bulk generation of hydrogen is one of the pivotal contemporary issues that requires immediate attention. In this work, we have synthesized trimetallic Zn-Co-Ni selenide nanoparticles (NPs) via a one-step hydrothermal method and explored their efficacy toward the electrocatalytic hydrogen evolution reaction (HER). The X-ray diffraction pattern investigations revealed that Zn and Co were doped into the cubic structure of NiSe₂. Among the different compositions synthesized, trimetallic Zn_0.1Co_0.3Ni_0.6Se₂ NPs demonstrated excellent electrocatalytic activity toward HER with a lesser overpotential of 121 mV at 10 mA cm^-2 and a relatively lower Tafel slope of 35.3 mV dec^-1. Further, the electrocatalyst shows very good long-term stability for a duration of 12 h at 10 mA cm^-2 in 0.5 M H₂SO₄. The morphological and structural investigations of Zn_0.1Co_0.3Ni_0.6Se₂ NPs were probed in detail to understand their electrocatalytic performance. The judicious combination of the trimetals in an appropriate ratio is expected to modulate the electronic structure and trigger the electronic conductivity and active surface area, which, in turn, could boost the electrocatalytic HER process. Also, the various valence states of three different metal ions would afford a larger number of active sites in the trimetallic selenide NPs.