Synthesis of Conical SiC Nanowhiskers From Hybrid Electrospun PVA / SiO 2 / MWCNT Nanofibers

ABSTRACT In this work, one‐dimensional silicon carbide (SiC) nanowhiskers (NWs) were successfully synthesized via catalyst‐free carbothermal reduction of electrospun hybrid nanofibers composed of polyvinyl alcohol, silica, and multi‐walled carbon nanotubes (MWCNTs). The morphology and microstructure of the precursor and final product were characterized using field‐emission scanning electron microscopy, Fourier‐transform infrared spectroscopy, raman spectroscopy, X‐ray diffraction, and transmission electron microscopy. The results revealed that the synthesized NWs were single‐crystal SiC with uniform conical morphology without catalyst at the tip, confirming a catalyst‐free growth mechanism. The growth behavior of the NWs strongly depended on the structural orientation and composition of the precursor. It was observed that the presence of MWCNTs enhanced the surface contact between carbon and silica sources, thereby promoting more uniform and efficient SiC formation. Additionally, the study demonstrates that oriented nanofibers yielded longer and thinner NWs compared to the random ones. The synthesized NWs exhibited high thermal stability in the ambient atmosphere at 1000°C. The results highlighted that the type, morphology, and structure of the precursor significantly influenced the thermodynamics and kinetics of nucleation and growth, ultimately leading to the formation of tip‐thickening one‐dimensional SiC nanostructures. The vapor–solid mechanism was proposed as a potential mechanism for synthesizing single‐crystal SiC NWs.