Novel SiOC nanocomposites for high-yield preparation of ultra-large-scale SiCnanowires

Abstract

Novel SiOC nanocomposites were successfully synthesized from commercial silica sol andsucrose via a simply designed route. The formation of SiOC nanocomposites was studied usingthermogravimetry and differential scanning calorimetry. The synthesized nanocomposites werecharacterized by Fourier transform infrared spectroscopy, x-ray fluorescence spectrometer,x-ray photoelectron spectroscopy, x-ray diffraction, scanning electron microscopy, andtransmission electron microscopy. The results indicate that the synthesized composites areamorphous in nature and homogeneous with the microstructure of close packedSiO2 and carbon at nanoscale. The SiOC nanocomposites exhibit veryhigh reactivity and can be annealed to produce SiC nanocrystals at1200 °C which isabout 300 °C lower than the value obtained by thermodynamic calculation. Ultra-large-scaleβ-SiCnanowires with high quality were prepared by directly annealing the synthesized SiOC nanocompositesat 1500 °C under Ar atmosphere, where the yield of SiC nanowires was up to 59%. TheSiC nanowires grow along the [111] direction with highly uniform diameters ofabout 100 nm. Experimental results indicate that the close contact betweenSiO2 and carbon at nanoscale plays a vital role in the high yield of SiC nanowires. The presentwork provides an efficient strategy for the large scale production of high-quality SiCnanowires.