Fabrication of graphene/Ni-Ce mixed oxide with excellent performance for reducing fire hazard of polypropylene

A hybrid graphene/Ni-Ce mixed oxide (Gs-NiCexOy) was facilely fabricated using a co-precipitation and subsequent calcination route. Ni-Ce mixed oxide nanoparticles with a uniform diameter of 10-15 nm were assembled on the graphene nanosheets, as demonstrated by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. Subsequently, the Gs-NiCexOy hybrid was applied to reduce the fire hazards of polypropylene (PP). It was found that the thermal stability of PP composite was obviously enhanced upon the incorporation of 2.5 wt% Gs-NiCexOy. Furthermore, the addition of Gs-NiCexOy significantly improved the fire safety of PP composite, as evidenced by the dramaticl reduction of peak heat release rate, total heat release, smoke production rate, total smoke production and CO production rate. The total flammable gaseous products from the PP composite were decreased and residual char was increased with the addition of Gs-NiCexOy. The flame retardant mechanism was attributed to the combined effect of the physical barrier of graphene nanosheets and the high catalytic activity of the Ni-Ce mixed oxide. This work could allow opening the door to a future potent graphene based nanomaterial in the domain of risk.