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 PdxAgynanoparticles (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 PdxAgyNPs 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 PdxAgyNPs 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 m2g–1, and the great peak current density of 1501 mA cm–2mg–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.