Carbon-supported base metal nanoparticles : Cellulose at work

Pyrolysis of base metal salt loaded microcrystalline cellulose spheres gives a facile access to carbon-supported base metal nanoparticles, which have been characterized with temperature-dependent XRD, SEM, TEM, ICP-MS and elemental analysis. The role of cellulose is multifaceted: 1) it facilitates a homogeneous impregnation of the aqueous base metal salt solutions, 2) it acts as an efficacious (carbonaceous) support material for the uniformly dispersed base metal salts, their oxides and the metal nanoparticles derived therefrom, and 3) it contributes as a reducing agent via carbothermal reduction for the conversion of the metal oxide nanoparticles into the metal nanoparticles. Finally, the base metal nanoparticles capable of forming metastable metal carbides catalytically convert the carbonaceous support into a mesoporous graphitic carbon material. Mutually beneficial: Pyrolysis under inert conditions of base-metal-salt-loaded (CuII, NiII, CoII or FeIII) microcrystalline cellulose spheres gives homogeneously distributed carbon-supported base metal nanoparticles. Cellulose is converted into an amorphous carbon, which concurrently acts both as support and reductant. The nickel, cobalt, or iron nanoparticles catalyze the graphitization of the amorphous carbon support