Direct Electrosynthesis of Metal Nanoparticles on TiCT-Mxene during Hydrogen Evolution.

Herein, we propose a simple yet effective method to deposit metal nanoparticles on TiCT-MXene via direct electrosynthesis. Without using any reducing reagent or annealing under reducing atmosphere, it allows the conversion of metal salts (e.g., PtCl, RuCl·yHO, IrCl·zHO, AgNO, and CuCl·2HO) to metal nanoparticles with a small particle size (ca. 2 nm). Under these circumstances, it was realized that the support effect from TiCT-MXene (electron pushing) is quite profound, in which the TiCT-MXene support will act as an electron donor to push the electron to Pt nanoparticles and increase the electron density of Pt nanoparticles. It populates the antibonding state of Pt-Pt bonds as well as the adsorbate level that leads to a "weakening" of the Δ in the optimal position. This rationalizes the outstanding activity of Pt/TiCT-MXene (5 wt %, η = 16 mV) for the hydrogen evolution reaction (HER). In addition, this direct electrosynthesis method grants the growth of two or multiple types of metal nanoparticles on the TiCT-MXene substrate that can perform dual or multiple functions as desired. For instance, one can prepare an electrocatalyst with Pt (2.5 wt %) and Ru nanoparticles (2.5 wt %) on the TiCT-MXene support from the same synthetic method. This electrocatalyst (Pt_Ru/TiCT-MXene) can display good electrocatalytic HER performance in both acid (0.5 M HSO) and alkaline electrolytes (1.0 M KOH).