Abstract
The Ir/ZrO2 and Ir/SO4/ZrO2 systems were studied by diffuse-reflectance IR spectroscopy using CO as a probe molecule. After reduction of 0.5% Ir/ZrO2 in flowing hydrogen at 200°C, the state of iridium is essentially Ir0, as in the iridium systems supported on amphoteric oxide supports. For Ir/SO4/ZrO2, the stabilization of ionic forms of the metal, the formation of species with a partial positive charge, and an increase in the frequencies of CO adsorbed on Ir0 particles, as compared with systems without sulfur, are found. At a concentration as low as 0.1 wt.%, iridium exists substantially as Ir3+ ions or small Ir⋆+ particles. An increase in the concentration of iridium to 0.5 wt.% leads to the formation of the bulk Ir 0 n phase, whose fraction increases as the iridium content increases. This phase predominates in the samples with 2.5 wt.% iridium.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
A. Corma,Chem. Rev., 1995,95, 559.
X. Song and A. Sayari,Catal. Rev. Sci. Eng., 1996,38, 329.
T. Okuhara, N. Mizuno, and M. Misono,Adv. Catal., 1996,41, 113.
L. M. Kustov, T. V. Vasina, A. V. Ivanov, O. V. Masloboishchikova, E. G. Khelkovskaya-Sergeeva, and P. Zeuthen,Stud. Surf. Sci. Catal., 1996,101, 821.
A. V. Ivanov, T. V. Vasina. O. V. Masloboishchikova, E. G. Khelkovskaya-Sergeeva, L. M. Kustov, and P. Zeuther,Kinet. Katal., 1998,39 [Kinet. Catal., 1998,39 (Engl. Transl.)].
M. Hino and K. Arata,Catal. Lett., 1995,30, 2.
A. V. Ivanov, L. M. Kustov, T. V. Vasina, V. B. Kazansky, and P. Zeuthen,Kinet. Katal., 1997,38, 416 [Rinet. Catal., 1997,38 (Engl. Transl.)].
A. V. Ivanov, A. Yu. Stakheev, and L. M. Kustov,Kinet. Katal., 1997,38, 718 [Kinet. Catal., 1997,38 (Engl. Transl.)].
A. V. Ivanov and L. M. Kustov,Izv. Akad. Nauk, Ser. Khim., 1998, 57 [Russ. Chem. Bull., 1998,47, 55 (Engl. Transl.)].
A. V. Ivanov and L. M. Kustov',Izv. Akad. Nauk, Ser. Khim., 1998, 409 [Russ. Chem. Bull., 1998,47, 394 (Engl. Transl.)].
L. M. Kustov, A. A. Alekseev, V. Yu. Borovkov and V. B. Kazansky,Dokl. Akad. Nauk SSSR, 1981,261, 1374 [Dokl. Chem., 1981 (Engl. Transl.)].
V. Yu. Borovkov, Doct. Sci. (Chem.) Thesis, Institute of Organic Chemistry of the USSR Acad. Sci., Moscow, 1989 (in Russian).
A. S. Medin, Ph. D. (Phys-Math.) Thesis, Institute of Organic Chemistry of the USSR Acad. Sci., Moscow, 1990 (in Russian).
C. Morterra, R. Aschieri, and M. Volante,Mater. Chem. Phys., 1988,20, 539.
F. Solymosi, E. Novak, and A. Molnar,J. Phys. Chem., 1990,94, 7250.
F. J. C. M. Toolenaar, A. G. T. M. Bastein, and V. Ponec,J. Catal., 1983,82, 35.
T. Beutel, S. Kawi, S. K. Purnell, H. Knözinger, and B. C. Gates,J. Phys. Chem., 1993,97, 7284.
P. Gelin, A. Auroux, Y. Ben Taarit, and P. C. Gravelle,Appl. Catal., 1989,46, 227.
S. Kawi, J.-R. Chang, and B. C. Gates,J. Am. Chem. Soc., 1993,115, 4830.
A. A. Davydov,IK-spektroskopiya v khimii poverkhnostnykh akislov [IR Spectroscopy in the Chemistry of Surface Oxides], Nauka, Sib. Otd., Novosibirsk, 1984 (in Russian).
T. v. Voskobojnikov, E. S. Shpiro, H. Landmesser, N. Jaeger, and G. Schulz-Ekloff,J. Mol Catal., A., Chem., 1995, 299.
R. M. Hammaker, S. A. Francis, and R. P. Eischens,Spectrochim. Acta, 1965,21, 1295.
M. Scheffler,Surf. Sci., 1979,81, 562.
Author information
Authors and Affiliations
Additional information
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2192–2196, November, 1998.
Rights and permissions
About this article
Cite this article
Ivanov, A.V., Kustov, L.M. State of iridium supported on SO4/ZrO2 . Russ Chem Bull 47, 2124–2128 (1998). https://doi.org/10.1007/BF02494265
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02494265