Controllable Synthesis of a Loofah-Like Cobalt-Nickel Selenide Network as an Efficient Electrocatalyst for the Hydrogen Evolution Reaction.

The rational design and construction of noble metal-free electrocatalysts featuring high efficiency and low cost are important for the hydrogen evolution reaction (HER). A significant development in the synthesis of a loofah-like Co 0.6 Ni 0.4 Se 2 architecture (expressed as Co 0.6 Ni 0.4 Se 2 -LN) electrocatalyst on carbon cloth through a three-step method is reported. Both the ionic liquid 1-dodecyl-3-methylimidazolium acetate (IL, [C 12 MIm]Ac) and the molar ratio of Co to Ni play a pivotal role in the synthesis of Co 0.6 Ni 0.4 Se 2 -LN with 3D hierarchical architecture. Co 0.6 Ni 0.4 Se 2 -LN exposes abundant active sites and provides hierarchical and stable transfer channels for both electrolyte ions and electrons, which results in outstanding HER performance. Impressively, Co 0.6 Ni 0.4 Se 2 -LN shows a low overpotential of 163 mV at 10 mA cm -2 , a small Tafel slope of 40 mV dec -1 , and superior stability to continuously catalyze the generation of H 2 for 40 h. This study offers a new perspective to the synthesis of high-efficiency inexpensive electrocatalysts for HER and also presents a good example for investigating the potential application of ILs in the synthesis of functional materials.