Abstract
Large quantities of ZnO nanorods (>3 kg/h throughput) were produced in the gas-phase by flame spray pyrolysis (FSP) of a zinc nitrate–ethanol precursor solution without employing any catalysts or dopants. The nanorods with diameters of 20–30 nm and aspect ratios as high as seven were collected as a dry powder. Several rods self-aligned by forming junctions at the basal planes, while some even assembled into tetrapods. The aspect ratio of the nanorods could be controlled by the concentration of the Zn ions in the starting precursor solution, its delivery rate, and the oxygen flow into the reactor. To the best of our knowledge, this is the first time that synthesis of high aspect ratio ZnO nanorods by FSP is reported. Previous lab-scale experiments always yielded rather spherical albeit slightly elongated nanoparticles unless dopants were added. Such a product powder was obtained here when the ethanol in the precursor solution was replaced by methanol at otherwise constant process conditions. This is attributed to different temperature–time histories of the particles in the flame based on which a mechanism for ZnO nanorod formation in spray flames is proposed.
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References
Bacsa R, Kihn Y, Verelst M, Dexpert J, Bacsa W, Serp P (2007) Large scale synthesis of zinc oxide nanorods by homogeneous chemical vapour deposition and their characterisation. Surf Coat Technol 201:9200–9204
Bickmore CR, Waldner KF, Treadwell DR, Laine RM (1996) Ultrafine spinel powders by flame spray pyrolysis of a magnesium aluminium double alkoxide. J Am Ceram Soc 79:1419–1423
Cheary RW, Coelho AA (1992) Fundamental parameters approach to x-ray line-profile fitting. J Appl Crystallogr 25:109–121
Dai ZR, Pan ZW, Wang ZL (2003) Novel nanostructures of functional oxides synthesized by thermal evaporation. Adv Funct Mater 13:9–23
Graham SC, Robinson A (1976) A comparison of numerical solutions to the self-preserving size distribution for aerosol coagulation in the free-molecule regime. J Aerosol Sci 7:261–273
Gröhn AJ, Pratsinis SE, Wegner K (2012) Fluid-particle dynamics during combustion spray aerosol synthesis of ZrO2. Chem Eng J 191:491–502
Height MJ, Mädler L, Pratsinis SE, Krumeich F (2006) Nanorods of ZnO made by flame spray pyrolysis. Chem Mater 18:572–578
Heine MC, Pratsinis SE (2005) Droplet and particle dynamics during flame spray synthesis of nanoparticles. Ind Eng Chem Res 44:6222–6232
Iijima S (1991) Helical microtubules of graphitic carbon. Nature 354:56–58
Jossen R, Pratsinis SE, Stark WJ, Mädler L (2005) Criteria for flame-spray synthesis of hollow, shell-like, or inhomogeneous oxides. J Am Ceram Soc 88:1388–1393
Kar S, Dev A, Chaudhuri S (2006) Simple solvothermal route to synthesize ZnO nanosheets, nanonails, and well-aligned nanorod arrays. J Phys Chem B 110:17848–17853
Kisi EH, Elcombe MM (1989) Upsilon-parameters for the wurtzite structure of ZnS and ZnO using powder neutron diffraction. Acta Crystallogr C 45:1867–1870
Klimm D, Ganschow S, Schulz D, Fornari R (2008) The growth of ZnO crystals from the melt. J Crystal Growth 310:3009–3013
Klimm D, Schulz D, Ganschow S (2011) In: Bhattacharya P, Fornari R, Kamimura H (eds) Comprehensive semiconductor science and technology, vol 3. Elsevier, Amsterdam, pp 302–338
Lide DR (1998) CRC handbook of chemistry and physics, 78th edn. CRC Press, Boca Raton
Liewhiran C, Phanichphant S (2007) Influence of thickness on ethanol sensing characteristics of doctor-bladed thick film from flame-made ZnO nanoparticles. Sensors 7:185–201
Liu B, Zeng HC (2003) Hydrothermal synthesis of ZnO nanorods in the diameter regime of 50 nm. J Am Chem Soc 125:4430–4431
Mädler L, Kammler HK, Mueller R, Pratsinis SE (2002) Controlled synthesis of nanostructured particles by flame spray pyrolysis. J Aerosol Sci 33:369–389
Mosselman C, Dekker H (1975) Enthalpies of formation of n-alkan-1-ols. J Chem Soc 1:417–424
Mueller R, Jossen R, Kammler HK, Pratsinis SE, Akhtar MK (2004) Growth of zirconia particles made by flame spray pyrolysis. AIChE J 50:3085–3094
Pan ZW, Dai ZR, Wang ZL (2001) Nanobelts of semiconducting oxides. Science 291:1947–1949
Peng H, Yuan F, Bai L, Li J, Chen Y (2007) Plasma synthesis of large quantities of zinc oxide nanorods. J Phys Chem C 111:194–200
Singh J, Srivastava A, Tiwari RS, Srivastava ON (2005) Nucleation and growth of catalyst-free zinc oxide nanostructures. J Nanosci Nanotechnol 5:2093–2098
Strobel R, Pratsinis SE (2011) Effect of solvent composition on oxide morphology during flame spray pyrolysis of metal nitrates. Phys Chem Chem Phys 13:9246–9252
Tani T, Mädler L, Pratsinis SE (2002) Homogeneous ZnO nanoparticles by flame spray pyrolysis. J Nanopart Res 4:337–343
Tseng Y-K, Hsu H-C, Hsieh W-F, Liu K-S, Chen I-C (2003) Two-step oxygen injection process for growing ZnO nanorods. J Mater Res 18:2837–2844
Vayssieres L (2003) Growth of arrayed nanorods and nanowires of ZnO from aqueous solutions. Adv Mater 15:464–466
Wang ZL (2004) Zinc oxide nanostructures: growth, properties and applications. J Phys 16:R829–R858
Yan H, He R, Pham J, Yang P (2003) Morphogenesis of one-dimensional ZnO nano- & microcrystals. Adv Mater 15:402–404
Yao BD, Chan YF, Wang N (2002) Formation of ZnO nanostructures by a simple way of thermal evaporation. Appl Phys Lett 81:757–759
Acknowledgments
The authors thank Dr. Neha Habelkar of ARCI, Hyderabad, for TEM analysis. K. Wegner gratefully acknowledges funding from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007–2013)/ERC grant agreement no 247283.
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Hembram, K., Sivaprakasam, D., Rao, T.N. et al. Large-scale manufacture of ZnO nanorods by flame spray pyrolysis. J Nanopart Res 15, 1461 (2013). https://doi.org/10.1007/s11051-013-1461-4
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DOI: https://doi.org/10.1007/s11051-013-1461-4