Preparation of Pt/XC-72@C-N electrocatalysts by the in-situ carbonization of ionic liquid for methanol oxidation

•We employed ionic liquids as a new kind of nitrogen-doped carbon sources.•The coated layer can effectively inhibit the migration of the Pt nanoparticles.•N-doped carbon strength the electron-transfer and charge density of carbon atom.•The Pt/XC-72@C-N exhibits higher activity and durability than uncoated Pt/XC-72.

The Pt/XC-72 catalyst coated with a N-doped carbon layer (Pt/XC-72@C-N) for proton exchange membrane fuel cells (PEMFCs) with high performance has been synthesized by the in-situ carbonization of EMIm-dca ionic liquid layer coated on the conventional Pt/XC-72 catalyst. X-ray diffraction (XRD), energy dispersive of X-ray (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammograms (CV) and accelerated aging test (AAT) are applied to characterize the structure and performances of the catalyst. The results show that the resultant Pt/XC-72@C-N catalyst exhibits significantly improved electrocatalytic activity and prolonged durability for methanol oxidation compared to the uncoated Pt/XC-72 and the N-free coated catalysts. The high performance can be attributed to: 1) the migration and agglomeration of the Pt nanoparticles are inhibited due to the strong anchoring effect of the coated layer; and 2) the N-doped carbon layer not only benefits for improving charge transfer rate on the interface, but also promotes dispersion of the Pt nanoparticles and interaction between the negative Pt particles and the carbon support.

Graphical abstractAn ideal schematic illustration of Pt/XC-72 catalyst coated with N-doped carbon layer from carbonization of ionic liquids.Figure optionsDownload full-size imageDownload as PowerPoint slide