Limits...
Fe(NO3)3-assisted large-scale synthesis of Si₃N₄ nanobelts from quartz and graphite by carbothermal reduction-nitridation and their photoluminescence properties.

Liu S, Fang M, Huang Z, Huang J, Ji H, Liu H, Liu YG, Wu X - Sci Rep (2015)

Bottom Line: The large-scale synthesis of Si3N4 nanobelts from quartz and graphite on a graphite-felt substrate was successfully achieved by catalyst-assisted carbothermal reduction-nitridation.The Fe(NO3)3 played a crucial role in promoting the nanobelt formation in the initial stage.The room-temperature photoluminescence spectrum of Si3N4 nanobelts consists of three emission peaks centered at 413, 437, and 462 nm, indicating potential applications in optoelectronic nanodevices.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Technology, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, China University of Geosciences, Beijing, 100083.

ABSTRACT
The large-scale synthesis of Si3N4 nanobelts from quartz and graphite on a graphite-felt substrate was successfully achieved by catalyst-assisted carbothermal reduction-nitridation. The phase composition, morphology, and microstructure of Si3N4 nanobelts were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, and high-resolution transmission electron microscopy. The Si3N4 nanobelts were ~4-5 mm long and ~60 nm thick and exhibited smooth surfaces and flexible shapes. The Si3N4 nanobelts were well crystallized and grow along the [101] direction. The growth is dominated by the combined mechanisms of vapor-liquid-solid base growth and vapor-solid tip growth. The Fe(NO3)3 played a crucial role in promoting the nanobelt formation in the initial stage. The room-temperature photoluminescence spectrum of Si3N4 nanobelts consists of three emission peaks centered at 413, 437, and 462 nm, indicating potential applications in optoelectronic nanodevices.

No MeSH data available.


Proposed growth model of Si3N4 nanobelt.Normal topical Si3N4 nanobelt: (a) Fe droplet left on the surfaces of graphite felt substrate. (b) Fe reacted with both SiO and N2 to form Fe-Si-N eutectic liquid droplets and triangular tip of Si3N4 nanobelt began to show up. (c) Continual SiO and N2 were transported to the reaction site to form the Si3N4 along the growth direction. Si3N4 nanobelt with straight trail: (d) Fe droplet with a patch of solid refractory. (e) Nanobelt grew from Fe-Si-N eutectic droplets but it was hindered at a certain growth point by the solid refractory. (f) The Si3N4 nanobelt with straight trail continued to grow (the inset is the vertical sketch).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4355634&req=5

f7: Proposed growth model of Si3N4 nanobelt.Normal topical Si3N4 nanobelt: (a) Fe droplet left on the surfaces of graphite felt substrate. (b) Fe reacted with both SiO and N2 to form Fe-Si-N eutectic liquid droplets and triangular tip of Si3N4 nanobelt began to show up. (c) Continual SiO and N2 were transported to the reaction site to form the Si3N4 along the growth direction. Si3N4 nanobelt with straight trail: (d) Fe droplet with a patch of solid refractory. (e) Nanobelt grew from Fe-Si-N eutectic droplets but it was hindered at a certain growth point by the solid refractory. (f) The Si3N4 nanobelt with straight trail continued to grow (the inset is the vertical sketch).

Mentions: First, Fe(NO3)3 underwent thermal decomposition at a certain temperature to afford Fe2O3 (reaction 1). Then, Fe2O3 was reduced to Fe/FeO in the presence of C/CO (reactions 2 and 3), and the latter was left on the surface of graphite-felt substrate (Fig. 7a). It is generally accepted that the vapor phase of SiO plays an important intermediary role in CRN262728. With the increase in temperature, SiO vapor was produced by the reaction of SiO2 with raw material graphite (reaction 4) and/or by the reaction of SiO2 with CO vapor (reaction 5). When the SiO vapors diffuse to the surface of graphite-felt substrate, the Fe droplets react with both SiO and N2 in a short time to form Fe–Si–N eutectic liquid droplets (Fig. 7b). It has been reported that Fe catalyst catalyzes the formation of these eutectic liquid droplets, which may have promoted the nucleation of Si3N4 and played a dominant role in the primary formation of belt-like morphology15. In this study, Fe (NO3)3 was added in the initial stage and decomposed at a certain temperature. Owing to the strong adhesion between the eutectics and substrate, the Fe catalyst was not observed at the tip of nanobelts, rather acted as the root for the continuous growth of nanobelts. Notably, the residual reactant in graphite crucible was observed as shown in Fig. 6a. No belt-like product was obtained in all the horizons, further confirming the importance of Fe(NO3)3 in the growth of Si3N4 nanobelts.


Fe(NO3)3-assisted large-scale synthesis of Si₃N₄ nanobelts from quartz and graphite by carbothermal reduction-nitridation and their photoluminescence properties.

Liu S, Fang M, Huang Z, Huang J, Ji H, Liu H, Liu YG, Wu X - Sci Rep (2015)

Proposed growth model of Si3N4 nanobelt.Normal topical Si3N4 nanobelt: (a) Fe droplet left on the surfaces of graphite felt substrate. (b) Fe reacted with both SiO and N2 to form Fe-Si-N eutectic liquid droplets and triangular tip of Si3N4 nanobelt began to show up. (c) Continual SiO and N2 were transported to the reaction site to form the Si3N4 along the growth direction. Si3N4 nanobelt with straight trail: (d) Fe droplet with a patch of solid refractory. (e) Nanobelt grew from Fe-Si-N eutectic droplets but it was hindered at a certain growth point by the solid refractory. (f) The Si3N4 nanobelt with straight trail continued to grow (the inset is the vertical sketch).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4355634&req=5

f7: Proposed growth model of Si3N4 nanobelt.Normal topical Si3N4 nanobelt: (a) Fe droplet left on the surfaces of graphite felt substrate. (b) Fe reacted with both SiO and N2 to form Fe-Si-N eutectic liquid droplets and triangular tip of Si3N4 nanobelt began to show up. (c) Continual SiO and N2 were transported to the reaction site to form the Si3N4 along the growth direction. Si3N4 nanobelt with straight trail: (d) Fe droplet with a patch of solid refractory. (e) Nanobelt grew from Fe-Si-N eutectic droplets but it was hindered at a certain growth point by the solid refractory. (f) The Si3N4 nanobelt with straight trail continued to grow (the inset is the vertical sketch).
Mentions: First, Fe(NO3)3 underwent thermal decomposition at a certain temperature to afford Fe2O3 (reaction 1). Then, Fe2O3 was reduced to Fe/FeO in the presence of C/CO (reactions 2 and 3), and the latter was left on the surface of graphite-felt substrate (Fig. 7a). It is generally accepted that the vapor phase of SiO plays an important intermediary role in CRN262728. With the increase in temperature, SiO vapor was produced by the reaction of SiO2 with raw material graphite (reaction 4) and/or by the reaction of SiO2 with CO vapor (reaction 5). When the SiO vapors diffuse to the surface of graphite-felt substrate, the Fe droplets react with both SiO and N2 in a short time to form Fe–Si–N eutectic liquid droplets (Fig. 7b). It has been reported that Fe catalyst catalyzes the formation of these eutectic liquid droplets, which may have promoted the nucleation of Si3N4 and played a dominant role in the primary formation of belt-like morphology15. In this study, Fe (NO3)3 was added in the initial stage and decomposed at a certain temperature. Owing to the strong adhesion between the eutectics and substrate, the Fe catalyst was not observed at the tip of nanobelts, rather acted as the root for the continuous growth of nanobelts. Notably, the residual reactant in graphite crucible was observed as shown in Fig. 6a. No belt-like product was obtained in all the horizons, further confirming the importance of Fe(NO3)3 in the growth of Si3N4 nanobelts.

Bottom Line: The large-scale synthesis of Si3N4 nanobelts from quartz and graphite on a graphite-felt substrate was successfully achieved by catalyst-assisted carbothermal reduction-nitridation.The Fe(NO3)3 played a crucial role in promoting the nanobelt formation in the initial stage.The room-temperature photoluminescence spectrum of Si3N4 nanobelts consists of three emission peaks centered at 413, 437, and 462 nm, indicating potential applications in optoelectronic nanodevices.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Technology, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, China University of Geosciences, Beijing, 100083.

ABSTRACT
The large-scale synthesis of Si3N4 nanobelts from quartz and graphite on a graphite-felt substrate was successfully achieved by catalyst-assisted carbothermal reduction-nitridation. The phase composition, morphology, and microstructure of Si3N4 nanobelts were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, and high-resolution transmission electron microscopy. The Si3N4 nanobelts were ~4-5 mm long and ~60 nm thick and exhibited smooth surfaces and flexible shapes. The Si3N4 nanobelts were well crystallized and grow along the [101] direction. The growth is dominated by the combined mechanisms of vapor-liquid-solid base growth and vapor-solid tip growth. The Fe(NO3)3 played a crucial role in promoting the nanobelt formation in the initial stage. The room-temperature photoluminescence spectrum of Si3N4 nanobelts consists of three emission peaks centered at 413, 437, and 462 nm, indicating potential applications in optoelectronic nanodevices.

No MeSH data available.