Evidence for an oxygen intermediate in the catalytic reduction of NO by CO on rhodium surfaces

Dubois, L. H.; Hansma, Paul K.; Somorjai, Gábor A.

doi:10.1016/0021-9517(80)90309-7

Cited by 94 publications

(24 citation statements)

References 26 publications

(21 reference statements)

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“…At the same way, B11 sites will be adsorbed in which sites are easy to access due to the spatial effect and their higher binding energy. When the coverage increases, T2 and B22 sites of (111) step will be gradually adsorbed in, that's to say, the sequence of adsorption is that Tl, T2 sites are occupied at low coverage and then Bll, B22 sites are occupied with the increasing coverage, which sequence is completely agreeable with that of DeLouise [8] et al and Dubois [15] et al by XPS, LEED [8] and HREELS, AES[l5]. At the same time, the eigenvibration of 2018, 1987 cm-I ; 1969, 1927 cm-I of two kinds of adsorption sites respectively tally with the experiment.…”

supporting

confidence: 75%

“…The results of this work demonstrate the spectra of 2060, 1930 cm-I on the whole from HREELS [15] and the adsorption sequence of experiments [8,15]. The distinction between this work and the experiment is that CO molecules don not only adsorb in the top and bridge sites of (111) step.…”

Section: Resultsmentioning

confidence: 71%

“…For this bifurcation, it is necessary for deeper experimental and theoretical studies to demonstrate. In addition, the experimental work of DeLouise [8] et al Dubois [15] et al and this work provide some research data for the determination of the vibration dactylogram of (331) stepped surface. Hereon, this work predicts boldly that the vibration dactylogram of T sites of CO-Rh(331) system should be distributed in the area of 1987-2060 cm-I and that of B sites should be in the area of 1927-1969 cm-I .…”

mentioning

confidence: 88%

“…However, DeLouise [8] et al only pointed out that the top and bridge sites are adsorbed in but they did not show clearly the concrete location. Dubois [15] et al assigned 2060 cm-I to the top sites of (111) step by comparison with the infrared spectra [2,38] of model organometallic compounds of known molecular structure and assigned 1930 cm-I to the bridge sites of (111) step according to the infrared spectra of CO chemisorbed on either silica J38 ] or alumina J39 ] supported Rh particles and the result that CO is prone to dissociate on the step but not the terrace [40]. Of course, the activity and reactivity of 1018 mechanism of the step are not so simple by imagination and taken for granted.…”

mentioning

confidence: 98%

“…Dubois [15] et al obtained two frequencies of 2060, 1930 cm-I and assigned 2060 cm-I to the top site and 1930 cm-I to the stretch frequency of the bridge site on (111) step. DeLouise [8] et al considered that CO only adsorb in the top sites when the exposure :'(0.1 L, and CO adsorb in the top and bridge sites when 0.1 L:'(exposure :'( 1.5 L. They stated that their result agreed with that of Dubois [15] et al but they did not show clearly the idiographic position of the top and bridge sites.…”

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confidence: 99%

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Adsorption of CO molecules on Rh low index and (331) stepped surfaces

Wang¹

2004

Chinese Sci Bull

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The 5-parameter Morse potential (for short 5-MP) of the interaction between C, 0 atom and Rh surface and the extended LEPS potential have been constructed, and the adsorption and diffusion of CO molecules on Rh low index surfaces and open rough Rh(331) stepped surface are investigated. This work puts forward the concept of vibration dactylogram property for molecular adsorption states. The calculation results and the analysis of vibration dactylogram show that there exists the commonness in the adsorption on Rh low index surfaces and Rh(331) stepped surface: with the increasing coverage, the top, bridge sites are adsorbed in perpendicularly in sequence, and the top sites are the steady adsorption sites and the bridge sites are the next. On (100) surface, CO molecules obtain the eigenvibration of 2009, 1946 cm-1 on the top and bridge sites respectively and the difference between the binding energy of above two sites is 0.09 eV; on (110) surface, CO molecules obtain the eigenvibration of 2019, 1961 cm-1 respectively; on (111) surface, CO molecules on the top, bridge and hollow sites produce the eigenvibration of 2000, 1912, 1894 cm-1 respectively, the binding energies of the three sites decrease in tum and the discrepancy between the top and bridge sites is 0.03 eV; on (331) surface, top and bridge sites between two equivalent top sites are adsorbed in, and then obtain the eigenvibration of2018, 1987 cm-\ 1969, 1927 cm-1 respectively.The adsorption of carbon monoxide on single-crystal transition metal surfaces has received considerable attention by the surface science community. Not only can the chemisorption of CO on a metal surface be regarded as a model adsorption system but also its industrial importance is great in such areas as the catalysis of CO hydrogenation to produce hydrocarbons and of CO oxidation in controlling automobile exhaust [l]. The bonding of carbon monoxide to Rh is of special interest since this metal catalyzes the hydrogenation of CO in both heterogeneous and homogeneous media [2]. However, the adsorption and oxidation properties of CO at Rh surface have received much interest in the past, and with the increasing use of Rh as a component of the car exhaust catalyst, further interest has 1012 been recently simulated [3]. The scientists have adopted low energy electron diffraction, electron energy loss spectroscopy, infrared reflection absorption spectroscopy, etc. to perform the effective research, but the theoretical studies about this system are rare.For (100) surface, the researchers consider that top sites are adsorbed in at low coverage, and top and bridge sites will be occupied with increasing coverage. Of course, there are different viewpoints. Leung[4] et aI. assigned their obtained IRAS spectra to top, bridge sites, and point out explicitly the diversity of the binding energy between top and bridge sites is 0.1-0.4 kcal/mol and the bridge sites are the more stable species. Chang[5] et al. educed that bridge sites are adsorbed in firstly and then the top sites. Due to the complexity o...

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supporting

confidence: 75%

Section: Resultsmentioning

confidence: 71%

mentioning

confidence: 88%

mentioning

confidence: 98%

mentioning

confidence: 99%

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Adsorption of CO molecules on Rh low index and (331) stepped surfaces

Wang¹

2004

Chinese Sci Bull

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Reduction of NO by CO on Unsupported Ir: Bridging the Materials Gap

et al. 2010

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Temperature programmed desorption (TPD) and density functional theory (DFT) are used to investigate adsorption sites and reaction of coadsorbed NO and CO on planar Ir(210) and faceted Ir(210) with tailored sizes of three-sided nanopyramids exposing (311), (31 1) and (110) faces. Both planar and faceted Ir(210) are highly active for reduction of NO by CO with high selectivity to N(2), which is accompanied by simultaneous oxidation of CO. Evidence is found for structure sensitivity in adsorption sites and reaction of coadsorbed NO and CO on faceted Ir(210) versus planar Ir(210). Strong interaction between NO and CO at high NO exposure and one-monolayer CO pre-coverage results in "explosive" evolution of N(2) and CO(2) on planar Ir(210) and size effects in reduction of NO by CO on faceted Ir(210) for average facet size ranging from 5 to 14 nm without change in facet structure.

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An infrared spectroscopic study of CO and NO adsorption on bimetallic Pd‐Rh/SiO₂ catalysts

Mergler

Ramsaransing

Nieuwenhuys

1994

Recl. Trav. Chim. Pays‐Bas

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Abstract. Pure Pd/SiO,, pure Rh/SiO,, and bimetallic PdRh/SiO, catalysts, with Pd and Rh in the atomic ratios of 75/25 at% and 50/50 at%, were studied by means of infrared (IR) spectroscopy. Spectra of adsorbed CO and NO were recorded in the temperature range from 298 to 573K. The IR spectra obtained for the bimetallic catalysts exhibit characteristic features of both Pd and Rh. The results point to the presence of alloy crystallites with properties between those of the constituent metals. Most likely the PdRh(1: 1)/Si02 catalyst consists of small Rh clusters or atoms, surrounded by Pd, whereas for the PdRh(3 : 1)/Si02 catalyst the surface consists primarily of Pd. However, in the presence of NO, Rh migrates to the surface, due to the dissociation of NO and the concomitant oxidation of the metal particles. No indication of mixed sites, consisting of both Pd and Rh atoms, was found. The results are compared with those previously reported for Pt-Rh catalysts.

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Evidence for an oxygen intermediate in the catalytic reduction of NO by CO on rhodium surfaces

Cited by 94 publications

References 26 publications

Adsorption of CO molecules on Rh low index and (331) stepped surfaces

Adsorption of CO molecules on Rh low index and (331) stepped surfaces

Reduction of NO by CO on Unsupported Ir: Bridging the Materials Gap

An infrared spectroscopic study of CO and NO adsorption on bimetallic Pd‐Rh/SiO₂ catalysts

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Evidence for an oxygen intermediate in the catalytic reduction of NO by CO on rhodium surfaces

Cited by 94 publications

References 26 publications

Adsorption of CO molecules on Rh low index and (331) stepped surfaces

Adsorption of CO molecules on Rh low index and (331) stepped surfaces

Reduction of NO by CO on Unsupported Ir: Bridging the Materials Gap

An infrared spectroscopic study of CO and NO adsorption on bimetallic Pd‐Rh/SiO2 catalysts

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An infrared spectroscopic study of CO and NO adsorption on bimetallic Pd‐Rh/SiO₂ catalysts