Preparation of silicon carbide SiC-based nanopowders by the aerosol-assisted synthesis and the DC thermal plasma synthesis methods Cezary Czosnek a, *, Miroslaw M. Bu  cko b , Jerzy F. Janik a , Zbigniew Olejniczak c , Michal Bystrzejewski d , Olga Labe ˛d  z d , Andrzej Huczko d, * a AGH University of Science and Technology, Faculty of Energy and Fuels, al. A. Mickiewicza 30, 30-059 Krakow, Poland b AGH University of Science and Technology, Faculty of Materials Science and Ceramics, al. A. Mickiewicza 30, 30-059 Krakow, Poland c Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Krakow, Poland d University of Warsaw, Department of Chemistry, 1 Pasteura St., 02-093 Warsaw, Poland A R T I C L E I N F O Article history: Received 8 August 2014 Received in revised form 11 November 2014 Accepted 2 December 2014 Available online 4 December 2014 Keywords: A. Nanostructures A. Carbides C. X-Ray diffraction C. Infrared spectroscopy C. Nuclear magnetic resonance (NMR) A B S T R A C T Nanosized SiC-based powders were prepared from selected liquid-phase organosilicon precursors by the aerosol-assisted synthesis, the DC thermal plasma synthesis, and a combination of the two methods. The two-stage aerosol-assisted synthesis method provides at the end conditions close to thermodynamic equilibrium. The single-stage thermal plasma method is characterized by short particle residence times in the reaction zone, which can lead to kinetically controlled products. The by-products and final nanopowders were characterized by powder XRD, infrared spectroscopy FT-IR, scanning electron microscopy SEM, and 29 Si MAS NMR spectroscopy. BET specific surface areas of the products were determined by standard physical adsorption of nitrogen at 77 K. The major component in all synthesis routes was found to be cubic silicon carbide b-SiC with average crystallite sizes ranging from a few to tens of nanometers. In some cases, it was accompanied by free carbon, elemental silicon or silica nanoparticles. The final mesoporous b-SiC-based nanopowders have a potential as affordable catalyst supports. ã 2014 Elsevier Ltd. All rights reserved. 1. Introduction Silicon carbide SiC due to its high mechanical strength, semiconducting properties, chemical inertness, high-temperature stability, and good thermal conductivity has been a subject of numerous studies and growing applications. In addition to the established applications of bulk SiC, there are many utilizations that take advantage of its nanosized materials forms. For instance, SiC-based nanostructures were considered for nanoscale light emitters [1,2]. SiC membranes were shown to exhibit advanta- geous properties for gas separation [3–5]. SiC was also tried in diesel fuel particulate filters [6,7] and the carbide ceramic microreactors were investigated for hydrogen gas production [8,9]. In another approach, SiC was used as a support for the Ni catalyst in methane reforming to synthetic gas [10–12]. Several bottom-up precursor routes are available to prepare SiC powders. For example, they were synthesized by the carbothermal reduction method using the binary systems of the polysiloxane/phenol and polysiloxane/xylene resins [13]. Yang et al. reported a successful synthesis of SiC powders with particle sizes in the range of 0.5–1 mm by combustion synthesis from the mixtures of silicon, carbon black, and polytetrafluoroethylene powders [14]. Chemical vapor deposition synthesis in a hot-wall quartz reactor was used to make nanosized cubic b-SiC with crystallite sizes in the range of 10–30 nm using hexamethyldisilane as a precursor [15]. Du et al. described a route for making b-SiC by electric pulses discharged in liquid-phase organosilicon precursors [16]. In recent reports, microwave heating at 1200  C of suitable mixtures of silicon, graphite, and aluminum powders yielded either a-SiC [17] or aluminum-doped b-SiC [18]. Pure or boron-doped b-SiC powders were also produced by various combustion synthesis methods [19–23]. The thermal plasma synthesis offers a highly specific way to prepare nanopowders. The attractiveness of plasma processes stems, in general, from high energy densities in the reaction zone resulting in high precursor flow rates and increased temperatures, * Corresponding authors. Tel.: +48 12 617 2578. E-mail addresses: czosnek@agh.edu.pl (C. Czosnek), ahuczko@chem.uw.edu.pl (A. Huczko). http://dx.doi.org/10.1016/j.materresbull.2014.12.003 0025-5408/ ã 2014 Elsevier Ltd. All rights reserved. Materials Research Bulletin 63 (2015) 164–172 Contents lists available at ScienceDirect Materials Research Bulletin journa l homepage: www.elsevier.com/locate/matresbu