Abstract
It has been shown that the high-temperature hydrogen treatment of aluminum oxide nanowires coated with a monolayer of titanium oxide causes them to curl into nanotubes as a result of self-organization. The physicochemical properties of the nanotubes of a composite aluminum oxide aerogel coated with titanium oxide have been studied using X-ray phase analysis (XRD) and transmission electron microscopy (TEM). As a result of TiO2/Al2O3 nanofibrous aerogel treatment with hydrogen, a conversion of amorphous aluminum oxide fibers into tubes of nanocrystalline η-Al2O3 occurs, but in this case the titanium dioxide monolayer does not form a separate phase. A study of the porous structure by the low-temperature adsorption of nitrogen vapors has shown that the aerogels of TiO2/Al2O3 nanotubes have a developed mesoporous structure with a small amount of micropores and a specific surface of more than 300 m2/g. An increase in the temperature of hydrogen treatment first leads to the growth of an increase in the specific surface to 348 m2/g at 923 K, and then to a gradual decrease to 145 m2/g at 1123 K. In this case, the diameter of mesopores corresponding to a maximum on a curve of the pore size distribution decreases from 35 nm for a freshly prepared sample to 25 nm at 923 K and to 20 nm at 1123 K. The most homogeneous pores of a 25 nm diameter have the samples activated at 923 K. As a result of the high-temperature hydrogen treatment of the samples, the number of primary adsorption centers of water vapor adsorption decreases about two times. The resulting samples of TiO2/Al2O3 aerogels are close in structure to the initial aluminum oxide, whose wires just form nanotubes having a surface coated with titanium dioxide. As a result of the interaction between molecules of titanium dioxide adsorbed on the surface of aluminum oxide tubes, a substantial densification of the composite structure occurs.
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References
M. Liu and H. Yang, “Facile synthesis and characterization of macro–mesoporous Al2O3,” Colloids Surf. A: Physicochem. Eng. Asp. 371, 126–130 (2010).
X. Yuan, J. Zhu, K. Tang, Y. Cheng, Zh. Xu, and W. Yang, “Formation and properties of 1-D alumina nanostructures prepared via a template-free thermal reaction,” Proc. Eng. 102, 602–609 (2015).
A. El Kadib, K. Molvinger, Th. Cacciaguerra, M. Bousmina, and D. Brunel, “Chitosan templated synthesis of porous metal oxide microspheres with filamentary nanostructures,” Microporous Mesoporous Mater. 142, 301–307 (2011).
J.-L. Vignes, C. Frappart, T. di Costanzo, J.-C. Rouchaud, L. Mazerolles, and D. Michel, “Ultraporous monoliths of alumina prepared at room temperature by aluminium oxidation,” J. Mater. Sci. 43, 1234–1240 (2008).
O. K. Krasilnikova, A. S. Pogosyan, N. V. Serebryakova, T. Yu. Grankina, and A. N. Khodan, “Synthesis of carbon nanomaterials with porous alumina as a template,” Prot. Met. Phys. Chem. Surf. 44, 362 (2008).
O. K. Krasilnikova, A. S. Pogosian, N. V. Serebryakova, and T. Y. Grankina, “Synthesis of carbon materials with high porous alumina as template,” Adv. Chem. Res. 12, 177–204 (2011).
E. B. Markova, O. K. Krasilnikova, Yu. M. Serov, V. V. Kurilkin, and V. N. Simonov, “Alumina nanofibrous structural self-organization in hollow nanotubes caused by hydrogen treatment,” Nanotechnol. Russ. 9, 441–447 (2014).
E. B. Markova, O. K. Krasil’nikova, Yu. M. Serov, and V. V. Kopylov, “Study of nanofibrous catalysts based on aluminum and titanium oxides in propane cracking reactions,” Butler. Soobshch. 34 (4), 69–74 (2013).
J. Aarik, A. Aidla, V. Sammelselg, T. Uustare, M. Ritala, and È. M. Leskela, “Characterization of titanium dioxide atomic layer growth from titanium ethoxide and water,” Thin Solid Films 370, 163–172 (2000).
S. Gregg and K. Sing, Adsorption, Surface Area and Porosity (Academic Press, London, 1982; Mir, Moscow, 1984).
M. M. Dubinin, Chemistry and Physics of Carbon (Marcel Dekker, New York, 1966), Vol. 2, p. 51.
A. M. Voloshchuk, M. M. Dubinin, T. A. Moskovskaya, G. K. Ivakhnyuk, and N. F. Fedorov, “Pore structure and chemical state of the surface of carbon adsorbents Communication 1. Selection of the comparative isotherm of adsorption of nitrogen vapors on the surface of carbon adsorbents,” Russ. Chem. Bull. 37, 204–209 (1988).
E. P. Barrett, L. G. Joyner, and P. P. Halenda, “The determination of pore volume and area distributions in porous substances. I. Computations from nitrogen isotherms,” J. Am. Chem. Soc. 73, 373–380 (1951).
R. Sh. Vartapetyan and A. M. Voloshchuk, “The mechanism of the adsorption of water molecules on carbon adsorbents,” Russ. Chem. Rev. 64, 985–1001 (1995).
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Original Russian Text © O.K. Krasilnikova, E.B. Markova, V.N. Simonov, T.Yu. Grankina, A.S. Pogosyan, 2016, published in Rossiiskie Nanotekhnologii, 2016, Vol. 11, Nos. 3–4.
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Krasilnikova, O.K., Markova, E.B., Simonov, V.N. et al. Structural transformation of TiO2/Al2O3 nanowires into nanotubes caused by high-temperature hydrogen treatment. Nanotechnol Russia 11, 174–182 (2016). https://doi.org/10.1134/S1995078016020099
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DOI: https://doi.org/10.1134/S1995078016020099