One-Pot Water-Based Synthesis of Pt-Pd Alloy Nanoflowers and Their Superior Electrocatalytic Activity for the Oxygen Reduction Reaction and Remarkable Methanol-Tolerant Ability in Acid Media

Well-defined and strikingly monomorphic Pt-Pd alloy nanoflowers (Pt-Pd ANFs) with dominant {111} facets were successfully synthesized through a facile cochemical reduction method in a poly(allylamine hydrochloride) (PAR) based aqueous solution. The detailed morphology, composition, and structure of the Pt-Pd ANFs were investigated by transmission electron Microscopy (TEM); selected-area electron diffraction (SAED), energy dispersive spectrum (EDS), nitrogen adsorption-desorption isotherms, (SADI), EDS mapping, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), demonstrating the Pt-Pd ANFs were highly porous and a self-supported structure. The formation mechanism of the Pt-Pd ANFs were investigated by TEM and Fourier transform infrared (FT-IR), indicating that the existence of PAH and rapid growth of crystal, nuclei were essential for the formation of the Pt-Pd ANFs. The electrocatalytic activity and stability of the Pt-Pd ANFs for the oxygen reduction reaction (ORR) were investigated by rotating disk electrode voltammetry in 0.1 M HClO4 solution. The electrochemical tests indicated the {111}-enclosed Pt-Pd ANFs exhibited superior ORR activity along with satisfactory stability and methanol-tolerant. ability under acidic conditions,, which made them promising electrocatalysts for the future.