Infrared spectroscopic studies of dihydrogen adsorbed on oxide surfaces

Maslov, S. Y.; Denisenko, L. A.; Цыганенко, А. А.; Филимонов, В. Н.

doi:10.1007/bf02066309

Cited by 10 publications

(3 citation statements)

References 4 publications

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“…Both preparation and operation of the catalyst include its hydrogenation as an important step (Waugh 1992;French et al 2001aFrench et al , 2003b. The complex atomistic processes involved in sorption, reaction and then desorption of hydrogen from ZnO have captured the interest of both experimentalists and theoreticians (Taylor & Sickman 1932;Taylor & Strother 1934;Taylor & Liang 1947;Kubokawa & Toyama 1954;Low 1959Low , 1965Kubokawa 1960;Eischens et al 1962;Nagarjunan et al 1963;Peshev 1966;Dent & Kokes 1969;Morrison 1969;Narayana et al 1970a,b;Baraski & Galuszka 1976;Boccuzzi et al 1978;Watanabe 1978;Bowker et al 1981;Griffin & Yates 1982;Maslov et al 1982;Denisenko et al 1983;Roberts & Griffin 1986, 1988Burch et al 1990;Idriss & Barteau 1992;Waugh 1992;Ghiotti et al 1993;Nyberg et al 1996;Gines et al 1997;Mitra et al 1998;Lu et al 1999;Spencer 1999;Zapol et al 1999;Scarano et al 2001;Kazanskii & Pid'ko 2002;Kunat et al 2003;Rozovskii & Lin 2003;…”

Section: Hydrogen Dissociation Over Oxygen Terminated Polar Surface Of Al-doped Zno (A) Contextmentioning

confidence: 99%

Characterization of hydrogen dissociation over aluminium-doped zinc oxide using an efficient massively parallel framework for QM/MM calculations

et al. 2011

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A task-farm parallelization framework has been implemented in the ChemShell computational chemistry environment to provide a facility for parallelizing common chemical calculations, including finite-difference Hessian evaluation, the nudged elastic band method for reaction path optimization, and population-based methods for global optimization. The optimization methods are provided by a parallel interface to the DL-FIND optimization library. As ChemShell can already exploit parallel external programs for energy and gradient evaluations, the new methods result in a two-level approach to parallelization that gives significantly improved performance for massively parallel calculations. For typical systems, speed-up factors of five to eight times have been observed compared with non-task-farmed calculations. The task-farming version of ChemShell has been used to study the heterolytic dissociation of a hydrogen molecule over a polar oxygen-terminated surface of aluminium-doped zinc oxide using an embedded cluster hybrid QM/MM approach. We calculate a 42 kcal mol −1 heat of reaction and a 30 kcal mol −1 activation energy, which is equivalent to a high backward reaction barrier of 72 kcal mol −1 per H 2 molecule, in close agreement with temperature programmed desorption experiments. The dissociation path includes a stable intermediate comprising a hydride ion in an oxygen vacancy and physisorbed atomic hydrogen.

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Section: Hydrogen Dissociation Over Oxygen Terminated Polar Surface Of Al-doped Zno (A) Contextmentioning

confidence: 99%

Characterization of hydrogen dissociation over aluminium-doped zinc oxide using an efficient massively parallel framework for QM/MM calculations

et al. 2011

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“…As observed in Figure 7A, the amount of N2(a) under 650 Torr of N2(g) reached a maximum at 180 K during the warming procedure and it stayed during recooling. We consider Nz(g) and N2(a) are in equilibrium above 180 K. Assuming Langmuir adsorption, the formula for the calculation of heat of adsorption is; [9][10][11][12][13][14][15][16][17][18][19][20] where Keq is the equilibrium constant and ON2 and P N~ represent the coverage and the gas phase pressure of N2, respectively. Here, ONz is regarded as equal to the ratio AN~IAN~"'~', where AN-?…”

Section: Resultsmentioning

confidence: 99%

“…Adsorption of H2 has been also studied for probing coordination-unsaturated surface sites of ZnO,10 ZrCh," and others. 12 The IR-inactive feature of N2 and H2 in the gas phase enabled observation of adsorbed species at relatively high pressure because they become observable as a result of interaction with solid surfaces.…”

Section: Introductionmentioning

confidence: 99%

Preparation of a SiO2-Pillared K0.8Fe0.8Ti1.2O4 and IR Study of N2 Adsorption

Kondo¹,

Shibata²,

Ebina³

et al. 1995

J. Phys. Chem.

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The interlayer space of &.~Fe0.8Ti~,20~ was expanded by Si02-pillaring. The length of the interlayer spacing and surface area were increased by pillaring from 0.78 to 1.98 nm and from 0.4 to 154 m2-g-', respectively. N2 adsorption on the Si02-pillared &.~Feo.~Ti1.204 was studied by infrared (IR) spectroscopy. Two types of adsorbed N2 were observed at 2330 and 2350 cm-I. The former showed ordinary adsorption on oxides (AHH, = ca. 1 kcal/mol) and the latter indicated activated adsorption (AHa = ca. 6 kcal/mol), where migration into the pillared interlayers is considered to be the rate-determining step. IntroductionLayered niobates and titanates have been reported to be effective photocatalysts including photodecomposition of H20 into H2 and 02.'-3 However, band gaps of those compounds are only adequate for the use of ultraviolet light and are not capable for utilizing visible light. Recently, attempts were made to take other elements into the niobate layers in order to prepare a photocatalyst that absorbs light in the visible regione4 Another breakthrough to construct more efficient photocatalysts is to further modify their interlayers. Generally, the high efficiency of the layered compounds compared with that of bulk-type photocatalysts arise by direct transfer of holes and electrons excited in layers by irradiation to intercalated reactant mole c u l e~. ' .~,~ However, intercalation of water is undertaken by hydration of layers and the amount of intercalated water is limited. This problem seems to be solved if interlayers of a layered compound are widened by pillaring inorganic oxides.ss6Characterization of catalysts by means of IR spectroscopies on various probing molecules is now a common technique. Among them, pyridine and ammonia are especially well suited for monitoring acidities of catalysts such as zeolite^.^^^ Recently, the advantage of employing small molecules in a characterization of surface sites of solid catalysts has been demonstrated. N2 was used for probing both Lewis and Bronsted acid sites of zeolites9 The molecule is small enough to probe micropores and its weak basicity neglects well weak acid sites. Adsorption of H2 has been also studied for probing coordination-unsaturated surface sites of Zn0,'O Zr02," and others.'* The IR-inactive feature of N2 and H2 in the gas phase enabled observation of adsorbed species at relatively high pressure because they become observable as a result of interaction with solid surfaces.In this study, one of the candidates for visible light-responsive layered photocatalysts, b.~Feo.~Ti1.204, was prepared and its interlayers were pillared by Si02. Characterization of the produced catalyst was performed by IR spectroscopy of N2 adsorption. Experimental SectionA previously reported preparation method of Kx(MxTi2-x)04, where M represents a transition metal at 0.70 5 x 5 0.90, from ' Fax: 81-45-924-5276. @ Abstract published in Advance ACS Abstracts, October 1, 1995.K2CO3, TiO2, and a corresponding metal oxide13 was employed for production of Ko.sFeo.sTi1.204. Briefly,...

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Frequency limits of valence vibrations of free OH groups for several oxygen compounds

Trokhimets¹

1986

J Appl Spectrosc

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Infrared spectroscopic studies of dihydrogen adsorbed on oxide surfaces

Cited by 10 publications

References 4 publications

Characterization of hydrogen dissociation over aluminium-doped zinc oxide using an efficient massively parallel framework for QM/MM calculations

Characterization of hydrogen dissociation over aluminium-doped zinc oxide using an efficient massively parallel framework for QM/MM calculations

Preparation of a SiO2-Pillared K0.8Fe0.8Ti1.2O4 and IR Study of N2 Adsorption

Frequency limits of valence vibrations of free OH groups for several oxygen compounds

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