Preparation and Characterization of Ni-containing SiO2 or SiOC Composites from Rice Husk and Preceramic Polymer

Reference	Presenter	Authors (Institution)	Abstract
18-024	HELOISA PIMENTA MACEDO	MACEDO, H.P.(Universidade Federal do Rio Grande do Norte); Medeiros, R.L.(Universidade Federal do Rio Grande do Norte); Braga, R.M.(Escola Agricola de Jundiaí); MELO, D.M.(Universidade Federal do Rio Grande do Norte); Wilhelm, M.(Universität Bremen); Rezwan, K.(Universität Bremen);	Rice husk (RH) is a low cost and widely available agriculture waste that has been used as raw material for the production of silicon-based materials. Moreover, the addition of rice husk as fillers to organic polymer matrices has been reported as a strategy to improve the overall mechanical properties of composite ceramics. In this work, RH was used as catalytic support for Ni nanoparticles and showed good results for reactions as CO2 methanation and dry reforming of methane. For this application, it’s important that the material presents high surface area with well-dispersed metal particles, and also a hydrophobic behavior since water can reduce the catalytic activity. Accordingly, a relatively new concept is the application of metal-containing polymer derived ceramics for heterogeneous catalyzed reactions. In particular, Si-based preceramic polymers such as polysiloxanes, have attracted great attention due to their low cost, commercial availability, adjustable porosity and surface characteristics, chemical and thermal stability. Therefore, composites were prepared from a methylphenylpolysiloxane filled with RH previously impregnated with nickel. The RH acted as a metal-containing sacrificial template, which should generate after pyrolysis, a porous material with nickel nanoparticles embedded on the surface of the pores. The influence of RH loading (25-50wt%) and pyrolysis temperature (400/500/600°C in N2) was studied through TGA, TEM, XRD, N2 adsorption/desorption and water/heptane adsorption. The composites showed well dispersed Ni nanoparticles and presented lower weight loss, higher specific surface area and hydrophobic behavior when compared with a Ni-containing catalyst supported on RH. The weight loss increased with increasing RH loading and pryrolysis temperature. High surface area up to 480 m2/g was obtained for composite with lowest RH loading at 600°C. The hydrophilicity varied with the pyrolysis temperature. First catalytic results will be presented.
<< Back