Fabrication of PtNi bimetallic nanoparticles supported on multi-walled carbon nanotubes

Platinum/nickel bimetallic nanoparticles supported on multi-walled carbon nanotubes (xPtNi/CNTs) were synthesised. The fabrication process includes the chemical modification on the graphene surface of CNTs by acid treatment and the subsequent deposition of Pt or PtNi bimetallic nanoparticles with different compositions of Pt (x = 100, 90, 80 and 70wt%). The deposition was carried out using ethylene glycol as a reducing agent in the polyol method or using poly(amidoamine) dendrimer as a platform and sodium borohydride as a reducing agent to load the metal nanoparticles on the CNT surface. The structures of the produced PtNi/CNT nanoparticles were investigated by ultraviolet absorption spectra, X-ray diffraction (XRD) and the composite ratio consisting of 70wt% of metal content and 30wt% of CNTs was confirmed by the thermogravimetric analysis. The morphology and the phase identification of the produced PtNi/CNT nanoparticles were investigated by high-resolution scanning electron microscope, transmission electron microscope and XRD measurements. It was observed that the deposited Pt and PtNi bimetallic nanoparticles on the surface of CNTs had average particle sizes of 2-16nm, when they were prepared from the polyol method. On the other hand, the PtNi/CNT nanoparticles prepared by using a dendrimer as an intermediate had a smaller particle size and more uniform size distribution of the quantum dot size ranged from 2 to 4nm.