Journal of the American Ceramic Society, Vol.102, No.12, 7187-7197, 2019
High surface area SiC(O)-based ceramic by pyrolysis of poly (ethylene glycol) methacrylate-modified polycarbosilane
In the present work, a high surface area SiC(O)-based ceramic powder was synthesized upon thermal transformation of a polymer-derived macromolecular precursor, which was obtained by the chemical modification of a allylhyldrido polycarbosilane with poly(ethylene glycol) methaacrylate under argon environment. The pyrolysis of developed precursor led to the formation of amorphous and high surface area SiC(O)-based ceramic powder with in situ generated micro/meso-porosity. The specific surface area of the obtained powders depends on the processing temperature. It decreases from 363 to 122 m(2)/g as the pyrolysis temperature increases from 600 to 1200 degrees C, respectively. Furthermore the promising samples were fabricated using pressing technique, which led to crack-free SiC(O) monoliths on subsquent heat treatment. The present study also emphasizes the potential of produced SiC(O) ceramic powder to support NiO catalyst. The impregnation method were used to produce high surface area NiO@SiC(O) ceramic powder (NiO as a catalyst; SiC(O) as a catalyst support) for further catalytic applications. Interestingly, the distribution of the NiO was shown to strongly depend on the oxygen content present in the SiC(O) matrix. Thus, larger oxygen contents induce homogeneously distributed flower-like NiO catalyst onto SiC(O).
Keywords:allylhydrido polycarbosilane;poly(ethylene glycol) methaacrylate;polymer-derived ceramics (PDCs);porosity;SiC