Decoration of Carbon Nanomaterial Powders with Dispersed Platinum Metal Particles

Resumo

Carbon nanomaterials (fullerite, detonation nanodiamonds, Taunit, fullerenol, fullerene-containing black) were decorated with platinum group metal nanoparticles in situ in one step by low-temperature combustion (~250–270°С) of a powdered mixture of platinum metal acetylacetonate [Pt-M(асас)_n, Pt-М = Pt(II), Pd(II), Rh(III), Ir(III), acac = CH₃COCHCOCH₃, n is the oxidation state of Pt-М] with carbon nanomaterials in air. As shown by thermal analysis, the process is based on thermal oxidative degradation of the organometallic complex, catalyzed by carbon nanomaterials, with oxidation (combustion) of the organic moiety and release of the metal into the condensed phase. The thermal process in an open system occurs in the glowing mode (210–250°С); the size of the nanoparticles formed is 7–30 nm. Under the conditions restricting the air access to the reaction mixture and free outflow of gaseous products formed by oxidation of acac ligands, the nanoparticle size decreases to 3–10 nm. The particle size depends on the metal amount in the initial powder mixture and on the support morphology.