Synthesis of Silicon Carbide Nanowires from a Hybrid of Amorphous Biopolymer and Sol–Gel‐Derived Silica

Abstract

We report here the formation of silicon carbide (SiC) nanowires from inorganic–organic hybrid of sol–gel‐derived silica and the commercially available lignin that is naturally abundant amorphous biopolymer. This organic–inorganic hybrid material in the absence of catalyst was carbothermally reduced for a period of 1 h at 1400°C in inert atmosphere followed by oxidization. The nanostructures were characterized by scanning electron microscopy and high resolution scanning electron microscopy, which show the continuous formation of β‐SiC nanowires in the range of 50–200 nm diameter and length of few micrometers. Transmission electron microscopy revealed Y‐shaped structures (branched) of the nanowires grown in the direction of parallel to the [100] plane having two heads and one leg. The nanowires were formed with joints that were formed at regular intervals as circular rings. The deposition of silica layer on the outer surface of the nanowires was also observed. According to the X‐ray diffraction pattern, peaks at 2θ=35.9° and 59.8° indicate the formation of β‐SiC and a sharp peak at 2θ=22.1° suggests the presence of unreacted crystalline silica (crystoballite). The Raman shifts for β‐SiC appeared as small peaks at 795.6 and 983.1 cm−1, respectively. The characteristic vibration of SiC at 795 cm−1 in Fourier transform infrared spectroscopy was also observed.

Impact of Fluorination on Microstructures and Surface Properties of SiC Nanocomposites with SixCyFz Composition

“…Upon carbothermal reduction at 1400 °C in an argon atmosphere, the following reactions 1–6 take place, giving rise to SiC nanowires along with cristobalite and amorphous carbon. 21 Overall reactionThe β-SiC formed has shown nanowire dominance of 3C-SiC (dominance) prevalence and 6H SiC, with stacking faults as reported earlier. However, ammonium fluoride when incorporated into the system deteriorated the growth of SiC and gave rise to flat layered structures with gradual reduction of nanowires.…”

“…Upon carbothermal reduction at 1400 °C in an argon atmosphere, the following reactions 1−6 take place, giving rise to SiC nanowires along with cristobalite and amorphous carbon. 21…”

Large‐scale synthesis of ultralong single‐crystalline SiC nanowires

“…The length is estimated to be in the millimeter range based on the thickness of the NWs. Figure 2c and d reveals that these NWs with slightly fluctuating diameters of about 130 nm have an interesting bamboo‐like morphology 21 with many decorated knots along the whole NWs.…”

Synthesis and Growth Mechanism of SiC/SiO2 Nanochains Heterostructure by Catalyst‐Free Chemical Vapor Deposition

“…The coated amorphous layer was usually found on the surface of SiC nanowires as well. [15][16][17] The uneven gray level of the SiC/SiO 2 nanochain's crystal core indicates that a high density stacking faults exists in the SiC crystal core owing to the irregular deposition of Si and C atom layers. 18,19 The growth conditions fluctuation might result in atomic layers misarrangement in staking sequences.…”