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

This work developed a facile colloidal route to synthesize BH4-capped PdxAgy nanoparticles (NPs) in water using the reducing ionic liquids of [Cnmim]­BH4, 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 BH4 can create the profoundly exposed interfaces on the PdxAgy NPs during the electrooxidation, and favor the ethanol oxidation reaction (EOR) in lowering energy barrier. The counterions of [Cnmim]+ 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 PdxAgy 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 m2 g–1, and the great peak current density of 1501 mA cm–2 mg–1, Pd1Ag2@[C2mim]­BH4-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.