Infrared Spectroscopy for the Characterization of Surface Acidity and Basicity

Knözinger, Helmut

doi:10.1002/9783527610044.hetcat0059

Cited by 34 publications

(29 citation statements)

References 280 publications

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“…Infrared spectroscopy is a powerful tool to investigate oxides or supported metal catalysts [1][2][3][4]. Indirect information concerning nature and number of adsorption sites at the surface of the catalyst is retrieved by adsorption of appropriate probe molecules.…”

Section: Introductionmentioning

confidence: 99%

“…Indirect information concerning nature and number of adsorption sites at the surface of the catalyst is retrieved by adsorption of appropriate probe molecules. Carbon monoxide has been used frequently as a probe molecule based on non-reactive adsorption at cationic sites, [4] the formation of carbonyls with metals, [5,6] and the weak interaction with hydroxyl groups [2,7]. Alterations of the probed surface by possible redox reactions of CO with surface sites or the formation Abstract Carbon monoxide was applied as probe molecule to compare the surface of a ZnO-containing (Cu/ ZnO:Al) and a ZnO-free (Cu/MgO) methanol synthesis catalyst (copper content 70 atomic %) after reduction in hydrogen at 523 K by DRIFT spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

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IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer

et al. 2017

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer

et al. 2017

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“…The Lewis acid SbCl 5 was selected as a probe molecule, because it forms stable 1:1 adducts with all donors studied. Horill and Noller 27,28 have reported a linear correlation between this donicity of an organic base with the frequency shift of the silanol stretching vibration caused by its adsorption on silica (eq 3). On the basis of eq 3, ΔH don values were calculated for all compounds studied (see Table 3).…”

Section: Resultsmentioning

confidence: 99%

Basicity of Stereoregulating Electron-Donor Compounds in Ziegler–Natta Catalysts: A Study by Infrared Spectroscopy and Chemical Exchange Reactions

et al. 2014

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The Lewis basicity of typical electron donor compounds used to modify heterogeneous Ziegler−Natta catalysts, such as diakyl ethers, silyl ethers, esters, and ketones, was characterized by determining their effects on the IR frequency of surface silanol groups of silica gel, which correlate with the heat of this specific interaction and with their "donicity", i.e., with the heat of formation of their complexes with SbCl 5 . In this manner, ethers and silyl ethers are found to be more basic than ketones and esters. These differences in basicity are likely to affect the stereoregulating properties of such electron donor compounds in Ziegler−Natta polymerization catalysis. By consecutively adsorbing electron donors with various strengths on a MgCl 2 support, it was shown that weakly basic donors, such as ethyl benzoate or dibutyl phthalate, are partially displaced by donors with higher basicity, such as valerophenone and propyltrimethoxysilane. This indicates that the displacement of inner donors of the ester type from a titanium−magnesium catalyst upon addition of typical external donors, such as silyl ethers, is controlled by the relative basicities of these donor molecules.

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“…Electrochemical devices [56] and electrolysis of water [60] operated at ambient temperature and pressure [90] in small plants can be helpful in storage, electrochemical energy conversion process, and in transformation, as they require minimal capital investment. In electrochemical production of H 2 O 2 catalyst at the electrodes is of crucial importance so presently, the main challenge in focus is to find a material that can efficiently and selectively produce H 2 O 2 .…”

Section: Resultsmentioning

confidence: 99%

“…For reaching this goal an increasingly important role is played by the electrochemical devices; they require little auxiliary plants and can be operated at variable rates under ambient conditions. [90] Such devices can be coupled with alternating renewable power sources, like wind or solar power, and provides means to level out demand and store electricity. Herein, we focus on the electroreduction of oxygen to produce hydrogen peroxide.…”

Section: Electroreduction Of Oxygenmentioning

confidence: 99%

Recent progress on electrochemical production of hydrogen peroxide

Sehrish

Manzoor

et al. 2019

Chem Rep

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Hydrogen peroxide (H 2 O 2), first synthesized in 1818 through the acidification of barium peroxide (BaO 2) with nitric acid, is a clear and colorless liquid which is entirely miscible with water and variety of organic solvents such as carboxylic acid and esters. Anthraquinone process (an old production process of H 2 O 2), a batch process carried out in large facilities is an energy demanding process that requires large facilities, and involves oxidation of anthraquinone molecules and sequential hydrogenation. Moreover, the direct synthesis method enables production in a continuous mode as well as it permits small scale, decentralized production. Many drawbacks associated with these processes such as, energetic inefficiency and inherent disadvantages have motivated researchers, industry and academia to find out alternative for synthesis of H 2 O 2. Electrochemical route based on catalyst selectively reduce oxygen to hydrogen peroxide. O 2 is cathodically reduced to produce H 2 O 2 via 2-electron pathway or 4-electron pathway to get H 2 O. Electrolysis of water has an important place in storage and electrochemical energy conversion process where problem is to choose a sufficiently stable and active electrode for anodic oxygen evolution reaction. Most commonly used catalysts on the cathode are carbon based materials such as carbon black, carbon nanotubes, graphite, carbon sponge, and carbon fiber. In perspective of expanding demand of production and usage of hydrogen peroxide we review the past literature to summarize different production processes of H 2 O 2. In this review, we mainly focus on electrochemical production of hydrogen peroxide along with other alternatives, such as anthraquinone method for industrial H 2 O 2 production and direct synthesis process. We also review the catalytic activity, selectivity and stability for enhanced yield of H 2 O 2. From revision of last two decade's literature including experimental and theoretical data; we argue that successful implementation of electrochemical H 2 O 2 production can be realized on the basis of stable, active and selective catalyst.

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Infrared Spectroscopy for the Characterization of Surface Acidity and Basicity

Abstract: The sections in this article are Introduction Criteria for the Selection of Probe Molecules Characterization of Acid Sites on Solid Catalysts Characterization of Basic Sites on Solid Catalysts Conclusion

Cited by 34 publications

References 280 publications

IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer

IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer

Basicity of Stereoregulating Electron-Donor Compounds in Ziegler–Natta Catalysts: A Study by Infrared Spectroscopy and Chemical Exchange Reactions

Recent progress on electrochemical production of hydrogen peroxide

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