Ionic Liquid as Reaction Medium for Synthesis of Hierarchically Structured One-Dimensional MoO₂ for Efficient Hydrogen Evolution

Hierarchically structured one-dimensional (1D) MoO 2 is synthesized for the first time in ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([BMIM][Tf 2 N]). The synthesis system is very simple (single [BMIM][Tf 2 N] solvent plus MoO 2 (acac) 2 reactant). [BMIM][Tf 2 N] itself works as both the reaction medium and the template for the formation of these interesting 1D MoO 2 particles with ultrathin nanosheet subunits. The as-synthesized hierarchically 1D MoO 2 _ 40 particles exhibit remarkable electrocatalytic activity with good long-term cycle stability for the hydrogen evolution reaction (HER) in acidic media. The HER activity of present synthesized MoO 2 is comparable to those of the most active Mo-based electrocatalysts in acid media reported up to now. Therefore, the ionic liquid route provides us with a newly powerful tool for the synthesis of interesting alternative to noble metal catalysts for efficient electrocatalytic production of hydrogen in acidic environment.