Nickel-catalyzed in situ formation of carbon nanotubes and turbostratic carbon in polymer-derived ceramics

In Situ Carbon Nanotube Formation in Templated Pores of Polymer‐Derived Ceramics

“…[24,25] a methylphenylpolysilsesquioxane was impregnated with nickel acetate and converted in argon atmosphere into a PDC. Multi-walled carbon nanotubes (MWCNTs) were formed in the pores of the resulting composite and it was found that CNT formation started in the temperature range from 700 to 850 8C.…”

Synthesis and Properties of Porous Hybrid Materials containing Metallic Nanoparticles

“…5 a/b) although the metal content of ceramers is comparable to that of APT:Ni or APT:Pt ceramers. In spite of a very small Ni amount (<1 %) and the use of an oligomeric methylphenyl siloxanes (H44), Scheffler et al found a particle size of 40-60 nm in the resulting ceramer, [16] indicating a more effective separation of metal ions by complexation with APT and by monomeric PhT used in this work. Therefore, the diffusion of metal and the sintering of nanoparticles during preparation of ceramers is suppressed.…”

“…During pyrolysis even at 600°C the particle size was retained, indicating a remarkably stable embedding of particles in the ceramer matrix, preventing particle growth or sintering. In case of polysiloxanes containing Ni ions, the reduction took place at higher temperatures due to reaction with decomposing organic groups [16] and lead in APT:Ni 1:1 and 4:1 ceramers to separated spherical particles with a broader distribution of particles size in the range of 40-60 nm (1:1) and particle sizes around 50 nm (4:1), respectively. The bigger particle size compared to Pt particles in APT:Pt 208: 1 can be referred to the higher metal content in APT:Ni 1:1 and APT:Ni 4:1, which accounts for 35.2 or 16.3 wt.% compared to only 1.3 wt.% in APT:Pt 208:1 after pyrolysis at 500°C.…”

“…[2,13,14] Other groups used metal salts to introduce electrical conductivity or magnetic properties to SiOC materials [15] or investigated the Ni catalysed formation of carbon nanotubes in the resulting ceramics, which was observed applying temperatures beyond 800°C. [16] The size of Ni nanoparticles (< 1 wt.%) formed during pyrolysis from methylphenyl polysiloxanenickel acetate precursor came up with average diameters of 40-60 nm.A partial conversion of polysiloxane precursors below 800°C yields novel hybrid materials, which often exhibit high porosities and are therefore considered to be potential materials for adsorption and for catalyst supports. However, an adjusted design or functional testing of these hybrid materials in terms of sorption behaviour or catalytic activity has only been performed in far cases.…”

“…[2,13,14] Other groups used metal salts to introduce electrical conductivity or magnetic properties to SiOC materials [15] or investigated the Ni catalysed formation of carbon nanotubes in the resulting ceramics, which was observed applying temperatures beyond 800°C. [16] The size of Ni nanoparticles (< 1 wt.%) formed during pyrolysis from methylphenyl polysiloxanenickel acetate precursor came up with average diameters of 40-60 nm.…”