On the 2H- to 3C-Type Transformation and Growth Mechanism of SiC Nanowires upon Carbothermal Reduction of Rice Straws

Abstract

SiC nanowires (NWs) and nanoparticles (NPs) fabricated by carbothermal reduction of rice straws with/without FeSi catalysts were characterized by transmission electron microscopy to study the catalyst-facilitated vapor–liquid–solid (VLS) growth against the oriented attachment of the crystals, which underwent 2H- to 3C-type transformation. The cotectic melt of the FeSi catalyst in the Fe-Si-C-O system turned out to promote the VLS growth to form straight and occasionally tapered NWs in contrast to the zigzag ones via the (hkl)-specific coalescence of the faceted NPs. The SiC NWs showed [0001]2H-directed growth more or less stacked with {111}3C interlayers following the optimum crystallographic relationship (0001)2H//{111̅}3C; [21̅1̅0]2H//⟨101⟩3C with zigzag {111}3C lateral steps and polysynthetic twins/faults near the (0001)2H/(111)3C interface. The FeSi-assisted VLS growth and twinning/stacking fault-coupled 2H to 3C phase change may be extended to novel green manufacturing and design of sustainable resources for other semiconductor NWs.

Synthesis of 3C/2H/6H heterojunction SiC nanowires with high-performance supercapacitors by thermal evaporation

“…Liu et al 35 found that hexagonal 2H-, 6H-SiC segments embedded in the 3C matrix formed SFs. Similar results were found by Huang et al 64 and Chen et al , 30 but the content of each phase was not given by them quantitatively. According to calculations, the plane spacing of the (0002) plane in 2H-SiC (2.516 Å), and the (0006) plane in 6H-SiC (2.515 Å) were very close to that of the (111) plane in 3C-SiC (2.516 Å).…”

High-Yield Synthesis of SiC@SiO2 Core–Shell Nanowires on Graphite Substrates for Energy Applications

“…The formation of solid SiC@SiO 2 NWs occurs via gas–gas reactions between the intermediate gases of SiO and CO (as shown in Table S1). – The unavoidable presence of trace amounts of O 2 in the equipment, so in the Si–C–O systems, SiO gas should first be formed through possible solid–solid reactions or solid–gas reactions as follows: , 2 S i false( normals false) + O 2 ( g ) = 2 S i O false( normalg false) normalS normali normalO 2 ( s ) + normalC ( s ) = normalS normali normalO ( g ) + normalC normalO ( g ) normalS normali normalO 2 ( s ) + normalC normalO ( g ) = normalS normali normalO ( g ) + normalC normalO 2 ( g ) normalS normali normalO 2 ...…”

“…The formation of solid SiC@SiO 2 NWs occurs via gas–gas reactions between the intermediate gases of SiO and CO (as shown in Table S1). – The unavoidable presence of trace amounts of O 2 in the equipment, so in the Si–C–O systems, SiO gas should first be formed through possible solid–solid reactions or solid–gas reactions as follows: , …”