Monodisperse PdBi Nanoparticles with a Face-Centered Cubic Structure for Highly Efficient Ethanol Oxidation

Alloyed Pd-based nanocatalysts are considered as highly active fuel cell anodes toward the ethanol oxidation reaction (EOR). However, challenges remain in synthesizing free-standing monodisperse nanoparticles (NPs) with outstanding mass activity and long-term stability. In this work, PdBi NPs are synthesized by a one-step oil bath method with controllable sizes and compositions. The doping of Bi displays a positive effect on the oxidation of ethanol. The Pd8Bi NPs with an average size of 9.0 nm are found to possess an exceptional electrocatalytic mass activity with superior antitoxic ability and outstanding long-term stability toward EOR. These are mainly attributed to the change in the electronic structure and the d-band center of Pd, increase of the interatomic distance within a unit cell, and large electrochemically active surface area values, with lots of reaction sites provided by the morphology-optimized NPs. Higher electrocatalytic temperatures, higher pH values, and higher concentrations of C2H5OH accelerate each step of electro-oxidation on EOR. The density functional theory calculations demonstrate that the energy barrier of PdBi NPs can be reduced by adjusting the Bi content, resulting in excellent electrocatalytic activity toward EOR. This work provides a promising strategy to prepare monodisperse PdM alloys as efficient catalysts for fuel electro-oxidation.