Using ionic liquid as the solvent to prepare Pd–Ni bimetallic nanoparticles by a pyrolysis method for ethanol oxidation reaction

• Introducing ionic liquids to the pyrolysis process for the preparation of PdxNiy nanoparticles.
• PdxNiy nanoparticles with an average particle size of ∼7.0 nm were fabricated.
• The peak current of EOR was about three times higher at Pd1Ni1.5 compared to those of Pd.

Room temperature ionic liquids (RTILs) of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4) is used as the solvent for the first time to prepare multi-walled carbon nanotubes (MWCNTs) supported nanocomposite catalysts of PdxNiy (atomic ratios of Pd to Ni are 1:1, 1:1.5, 1:2, and 1:2.5) nanoparticles (denoted as PdxNiy/MWCNTs) by using a simple pyrolysis process. The PdxNiy/MWCNTs catalysts are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results show that the PdxNiy nanoparticles (NPs) are quite uniformly dispersed on the surface of MWCNTs with an average crystallite size of ∼7.0 nm. The electro-catalytic activity of the PdxNiy/MWCNTs catalysts for ethanol oxidation reaction (EOR) is examined by cyclic voltammetry (CV). It is revealed that the onset potential is ∼80 mV lower and the peak current is about three times higher for ethanol oxidation for MWCNT catalysts with Pd1Ni1.5 compared to those of Pd/MWCNTs. The catalytic mechanisms of the Pd1Ni1.5/MWCNTs towards EOR are also proposed and discussed.