Porous Polymer Derived Ceramics Decorated with in‐situ Grown Nanowires

Growth of One‐Dimensional Nanostructures in Porous Polymer‐Derived Ceramics by Catalyst‐Assisted Pyrolysis. Part II: Cobalt Catalyst

“…While a high C:O ratio involves the consumption of oxygen during crystallization, and therefore Si 3 N 4 is produced, a low C:O ratio enables the formation of Si 2 N 2 O. Indeed, parallel experiments performed using a low carbon‐containing polysiloxane (MK, Wacker Chemie AG, Munich, Germany, carbon ∼13 wt% 48 ) and a similar catalyst source yielded Si 2 N 2 O 31 . This implies that in the present experimental conditions (i.e., the use of a high carbon‐containing precursor, H44, carbon ∼40 wt% 48 ), the partial pressure of oxygen was always kept lower than that required to form Si 2 N 2 O.…”

“…An application of this processing concept to the growth of nanofibers on the surface of cellular polymer‐derived ceramic has been recently pursued by Yoon et al 30 . and in our laboratory 28,31 . The first authors reported the formation of highly aligned macroporous SiC ceramics decorated with homogenously distributed SiC nanowires, produced by unidirectional freeze casting of SiC/camphene slurries with different amounts of the PCS precursor.…”

“…Iron, an unwanted impurity in the starting SiC powder, was the catalyst enabling the growth of the nanowires, which afforded SSA values ranging from 30 to 86 m 2 /g, depending on the length of the nanostructures. The work in our laboratory has focused on the deliberate one‐pot synthesis of foams with hierarchical porosity via CAP using different catalysts (Fe, Co) and polysiloxanes 28,31 . Cellular SiOC ceramics, possessing a large amount of interconnected porosity, were produced by direct foaming, and the addition of a catalyst enabled the formation of 1D nanostructures (nanowires) in large quantity on the surface of the cell walls.…”

Fabrication and properties of ceramic 1D nanostructures from preceramic polymers: a review

“…76 In an another very recent study, 77 Si wafer was coated with 5-20 nm Fe film using a magnetron sputtering, the coated wafer was separated from a cured and crushed PHPSZ precursor which was put inside an alumina crucible, following by the pyrolysis at 1100-1400uC for 2 h in N 2 . After completion of the treatment, white products characterised as network-like branched Si 3 N 4 nanowires were collected on the surface of the Si wafer.…”

“…dissimilarities in the silicon, carbon and nitrogen content of the formed pseudoliquid phases. 15,76,85 A schematic view shown in Fig. 8 summarises CAP utilising PPs to form Si based 1D nanostructures via VLS in the porous monolithic PDC components.…”