Fine tuning the surface acidity of titanate nanostructures
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The effect of protonation on the surface acidic properties of titanate nanowires (TiONWs) was investigated. Nanowires were synthesized by the alkali hydrothermal method which resulted in one dimensional nanostructures of large external surface area and well-defined lamellar interlayer structure. The Na+/H+ ratio in the structure can be tuned by ion-exchange. Our aim was to characterize the morphology of the as-synthesized nanostructures by HRTEM and SEM measurements and assess their surface acidity using in situ infrared spectroscopic measurements and temperature programmed desorption. It was found that the numbers of Lewis and Brönsted acidic sites in the Na-form and the H-form of the TiONWs is different. The ratio and the nature of acidic sites can be tuned by the ion exchange process. The wire-like morphology and the tunable acidity are features of titanate nanowires that may render them a promising material in various heterogeneous catalytic applications.
KeywordsTitanate nanowires Surface acidity Pyridine adsorption Solid acids
The financial support of the TÁMOP-4.2.2.A-11/1/KONV-2012-0047 and TÁMOP-4.2.2.A-11/1/KONV-2012-0060 projects and the EC FP7 INCO “NAPEP” network is acknowledged.
- Byrne, M.T., McCarthy, J.E., Bent, M., Blake, R., Gunko, Y.K., Horvath, E., Konya, Z., Kukovecz, A., Kiricsi, I., Coleman, J.N.: Chemical functionalisation of titania nanotubes and their utilisation for the fabrication of reinforced polystyrene composites. J. Mater. Chem. 17, 2351–2358 (2007)CrossRefGoogle Scholar
- Kónya, Z., Hannus, I., Kiricsi, I.: Infrared spectroscopic study of adsorption and reactions of methyl chloride on acidic, neutral and basic zeolites. Appl. Catal. B Environ. 8, 391–404 (1996)Google Scholar
- Peng, C.W., Richard-Plouet, M., Ke, T.Y., Lee, C.Y., Chiu, H.T., Marhic, C., Puzenat, E., Lemoigno, F., Brohan, L.: Chimie douce route to sodium hydroxo titanate nanowires with modulated structure and conversion to highly photoactive titanium dioxides. Chem. Mater. 20, 7228–7236 (2008)CrossRefGoogle Scholar
- Wu, M.C., Hiltunen, J., Sapi, A., Avila, A., Larsson, W., Liao, H.C., Huuhtanen, M., Toth, G., Shchukarev, A., Laufer, N., Kukovecz, A., Konya, Z., Mikkola, J.P., Keiski, R., Su, W.F., Chen, Y.F., Jantunen, H., Ajayan, P.M., Vajtai, R., Kordas, K.: Nitrogen-doped anatase nanofibers decorated with noble metal nanoparticles for photocatalytic production of hydrogen. ACS Nano 5, 5025–5030 (2011)CrossRefGoogle Scholar