Carbon-riveted Pt catalyst supported on nanocapsule MWCNTs-Al2O3 with ultrahigh stability for high-temperature proton exchange membrane fuel cells

Pt catalyst supported on nanocapsule MWCNTs-Al2O3 (multi-walled carbon nanotubes, MWCNTs) catalyst has been prepared by microwave-assisted polyol process (MAPP). The results of electrochemical measurements show that the nanocapsule Pt/MWCNTs-Al2O3 catalyst has higher activity due to more uniform dispersion and smaller size of Pt nanoparticles, and higher stability ascribed to the stronger metal-support interaction (SMSI) between Pt nanoparticles and nanocapsule support than in Pt/MWCNTs. Furthermore, the carbon-riveted nanocapsule Pt/MWCNTs-Al2O3 catalyst has been designed and synthesized on the basis of in situ carbonization of glucose. The physical characteristics such as X-ray diffraction (XRD), energy dispersive analysis of X-ray (EDAX), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) have indicated that alpha-Al2O3 indeed entered into the inside of the MWCNTs and formed a nanocapsule support of MWCNTs with alpha-Al2O3 as stuffing. The accelerated potential cycling tests (APCT) show that carbon-riveted nanocapsule Pt/MWCNTs-Al2O3 possesses 10 times the stability of Pt/C and has 4.5 times the life-span of carbon-riveted Pt/TiO2-C reported in our previous work. The significantly enhanced stability for carbon-riveted nanocapsule Pt/MWCNTs-Al2O3 catalyst is attributed to the reasons as follows: the inherently excellent mechanical resistance and stability of alpha-Al2O3 and MWCNTs in acidic and oxidative environments; SMSI between Pt nanoparticles and the nanocapsule support; the anchoring effect of the carbon layers formed during the carbon-riveting process (CRP); the increase of Pt(0) composition during CRP.