Organotrialkoxysilane-mediated synthesis of Ni-Pd nanocatalysts at lower concentrations of noble metal: Catalysts for faster hydrogen evolution kinetics

Abstract

The fabrication of alkoxysilane-based nickel (Ni)-palladium (Pd) bimetallic nanoparticle catalysts with several compositions (Pd—0.001M and Ni—0.001-0.1M) was attempted for the first time; these materials were investigated for use as low-cost catalysts in the hydrogen evolution reaction (HER). Functional alkoxysilane [2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane]-assisted conversion of Pd2+ to Pd0 was demonstrated. Palladium nanocrystallites with an average dimension 4.03 ± 1.29 nm were synthesized, which acted as seeds in the synthesis of Ni-Pd bimetallic nanoparticles. The effect of the nanoparticle catalysts on the HER in an alkaline environment was studied using linear sweep voltammetry and electrochemical impedance spectroscopy. A nanostructured thin film containing Ni3PdNPs produced a 100 mA cm−2 current density at an overpotential of −90 mV with a small Tafel slope of 25 mV dec−1 at a catalyst loading of 0.1 mg cm−2. The annealed Ni3PdNPs catalyst further enhanced the current density to ∼ 240 mA cm−2 at an overpotential of −56 mV. © 2021 Author(s).