Journal of colloid and interface science | 2019
Monodispersed silver-palladium nanoparticles for ethanol oxidation reaction achieved by controllable electrochemical synthesis from ionic liquid microemulsions.
Abstract
Alloyed nanoparticles are promising electrocatalysts for electrochemical energy storage and conversion devices. However, syntheses of alloyed nanoparticles with controllable size and stoichiometry remain challenging. In this study, continuous, uniform and monodispersed bimetallic AgPd nanoparticles (NPs) with diameters ∼10\u202fnm are achieved by electrochemical synthesis from quaternary ionic liquid microemulsion (ILM) for use as electrocatalysts for ethanol oxidation reaction (EOR). It is found that the ionic liquid, 1-butyl-3-methyl-imidazolium chloride ([BMIM]Cl), acts not only as a soft template and co-surfactant for the formation of micro-reactors, but also as an electrolyte for enhancing conductivity. The stoichiometry (AgxPdy), size and size distribution of AgPd NPs can be accurately tuned by varying electrolyte composition, electrodeposition conditions, and ionic liquids concentrations. Attributed to the high surface area, optimal stoichiometric ratio, and strong attachment onto substrates without using organic binders, the as-deposited AgxPdy NPs exhibit extraordinary electrocatalytic activity and stability for EOR. It is found that the mass activity of Ag49Pd51 NPs/Pt electrode reaches 3360\u202fmA mg-1 for EOR in 1.0\u202fM ethanol and 1.0\u202fM KOH aqueous solution, which is much higher than commercial Pd/C catalyst (210.5\u202fmA mg-1) and also the highest among state-of-the-art AgPd NPs electrocatalysts reported to date for EOR in alkaline media.