A highly efficient and stable platinum film deposited via a mixed metal-imidazole casting method as a benchmark cathode for electrocatalytic hydrogen evolution

Abstract

Platinum-based materials are utilized as efficient catalysts for the hydrogen evolution reaction (HER) from water due to their optimal binding ability with hydrogen atoms. A platinum (Pt(w-MeIm)) film adhering rigidly on a glassy carbon (GC) substrate was prepared by a facile and scalable technique of a mixed metal-imidazole casting (MiMIC) method from a precursor solution containing H₂PtCl₆ in a mixed solvent of methanol/1-methyimidazole (MeIm) (3 : 1). The Pt(w-MeIm) film demonstrated a more efficient and stable HER performance compared with a platinum (Pt(w/o-MeIm)) film deposited from the precursor solution without MeIm due to closely-compacted and well-interconnected Pt nanoparticles for the Pt(w-MeIm) film. The Pt(w-MeIm) electrode provided an overpotential (η¹⁰) = 60 mV at a current density of 10 mA cm⁻², Tafel slope = 62 mV dec⁻¹ and a mass activity of 0.33 A cm⁻² mg_Pt⁻¹ at 100 mV in 1.0 M KOH solution, which are remarkably superior to those of the common Pt-based electrodes of commercially available Pt-loaded carbon (Pt/C) and the Pt plate. The Pt(w-MeIm) electrode is of keen interest as a new benchmark cathode for the HER.