Enhanced Electrocatalytic Activity of Ethanol Oxidation Reaction on Palladium–Silver Nanoparticles via Removable Surface Ligands

This work developed a facile colloidal route to synthesize BH 4 – -capped Pd x Ag y nanoparticles (NPs) in water using the reducing ionic liquids of [C n mim]BH 4, and the resulting NPs were prone to form the nanocomposites with [amim] + -modified reduced graphene (RG). The removal of the metal-free inorganic ions of BH 4 – can create the profoundly exposed interfaces on the Pd x Ag y NPs during the electrooxidation, and favor the ethanol oxidation reaction (EOR) in lowering energy barrier. The counterions of [C n mim] + can gather ethanol, OH – ions, and the reaction intermediates on catalysts, and synergistically interact with RG to facilitate the charge transfer in nanocomposites. The interface-modified RG nanosheets can effectively segregate the Pd x Ag y NPs from aggregation during the EOR. Along with the small size of 4.7 nm, the high alloying degree of 60.2%, the large electrochemical active surface area of 64.1 m 2 g –1, and the great peak current density of 1501 mA cm –2 mg –1, Pd 1 Ag 2 @[C 2 mim]BH 4 -amimRG nanocomposite exhibits the low oxidation potentials, strong poison resistance, and stable catalytic activity for EOR in alkaline media, and hence can be employed as a promising anodic catalyst in ethanol fuel cells.