Special Issue "Catalytic Decomposition of N2O and NO"
Deadline for manuscript submissions: 31 December 2020.
Interests: Chemical and reactor engineering, Environmental catalysis and photocatalysis, Adsorption on solids, Kinetics and mechanisms of chemical reaction, Abatement of N2O and NOx from waste gases
Nitrogen oxides NOx (NO, NO2) and N2O are significant pollutants and more than 90% of emitted NOx from stationary sources is NO. Various techniques have been developed for NO elimination, such as commercially commonly used selective catalytic reduction of NOx (SCR) and selective noncatalytic reduction of NOx (SNCR). In particular, less efficient SNCR technology will no longer be appropriate due to the tightening of emission limits. Compared to that, SCR NOx technology is very effective, but its disadvantage, like that of SNCR, is the need to add a reducing agent (ammonia, urea), which increases costs, causes undesirable ammonia slip, and requires increased safety precautions. From this perspective, the direct catalytic decomposition of NO without a reducing agent is a challenge. Mixed oxides with alkaline metal promoters appear to be active for this reaction, but there are a number of issues that need to be addressed. These are the stability of catalysts, sufficient activity at industrially suitable temperatures, and suppression of inhibition of the reaction by oxygen and other components present in the waste gases.
Well known greenhouse gas N2O is emitted from some processes together with NOx. Even in this case, a direct catalytic decomposition is the elegant method for reducing its emissions. This technology is now at the stage of its first commercial applications, for example, in nitric acid plants. However, there is still space for increasing its efficiency through the modification of the active site, deposition of the active phase on suitable support, etc.
Another issue is an indoor and outdoor environment, where nitrogen oxides can be decomposed in the presence of suitable semiconductor materials and light with appropriate wavelength and intensity. Research findings focusing on the fundamental exploration of the syntheses, characterizations, and applications of various types of catalysts for N2O or NO catalytic or photocatalytic decomposition, as well as new knowledge about the mechanism and industrial-scale development of catalysts are of prime importance to this Special Issue.
Prof. Dr. Lucie Obalová
Manuscript Submission Information
Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.
Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Catalysts is an international peer-reviewed open access monthly journal published by MDPI.
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- Direct NO catalytic decomposition
- N2O catalytic decomposition
- Photocatalytic decomposition of nitrogen oxides
- Semiconductor photocatalysts, TiO2
- Mixed oxide catalysts
- Supported catalysts
- Effect of promoters
- Relation between methods of preparation, physicochemical and catalytic properties
- Reaction mechanism and kinetics
The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.
Title: Magnesium effect in K/Co-Mg-Mn-Al mixed oxide catalyst for direct NO decomposition
Authors: K. Karásková, K. Pacultová, A. Klegová, D. Fridrichová, T. Kiška, K. Jirátová, L. Obalová
Abstract:Alkali metal promoted Co-Mn-Al mixed oxide catalysts were tested for direct NO decomposition. In this study, the effect of Mg partly substituting Co in the Co4MnAlOx mixed oxide catalyst subsequently modified by different potassium amount, maintaining (CoxMgy)/Mn/Al molar ratio constant, was studied. Prepared catalysts were characterized by XRD, BET, TPR-H2, TPD-CO2 and tested for direct NO decomposition in inert gas and in the presence of oxygen.
Title: Bulk and surface promotion of Co3O4 nanocrystals as a sensible tool for controlling the catalytic N2O decomposition
Authors: S. Wójcik, G. Grzybek, P. Stelmachowski, Z. Sojka, A. Kotarba
Abstract: Cobalt spinel nanocrystals, even in their bare state, have been recognized as a very active catalytic material for N2O decomposition. Their catalytic performance can be substantially modified by controlling the faceting of the nanocrystals and/or by proper doping with alien cations. These may located either in the bulk of the catalyst or on its surface. A particular attention is placed on the role of the tetra and octahedral interstitials, and the impact of the surface promoters as a potential hosting sites for the dopants. Both doping scenarios are analyzed in detail in the context of a rational design of the optimal active phase for an efficient low temperature N2O decomposition. The obtained experimental results are discussed in the broader context of the available literature data to establish the state-of-the-art of N2O decomposition over cobalt spinel catalysts.
Title: Atomic-level dispersion of bismuth over Co3O4 nanocrystals – outstanding promotional effect in catalytic deN2O
Authors: S. Wójcik1, T. Thersleff2*, K. Gębska1, G. Grzybek1, A. Kotarba1
Affiliation: 1Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland 2Department of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius & friends 16C 114 18 Stockholm, Sweden
Abstract: A series of cobalt spinel catalysts doped with bismuth in a broad range of 0 – 12 wt. % was prepared by the co-precipitation method. Catalysts were thoroughly characterized by several physicochemical methods (XRF, XRD, µRS, XPS, BET, WF), while the emphasis was put on the high resolution transmission electron microscopy (STEM, HAADF) coupled with EDX and EELS spectroscopies. The optimal concertation of the bismuth promoter was found to be 0.08 at.% (7.2 wt.%), which remarkably enhanced the performance of Co3O4, shifting down the deN2O temperature window by spectacular ΔT≈160°C. Since the addition of Bi results in work function increase, it is suggested that Bi promotes mostly the oxygen recombination step of the deN2O reaction. Microscopic observations allowed for revealing that the high activity of Bi-Co3O4 catalyst is associated with an even, atomic-level dispersion of bismuth promoter over the surface of cobalt spinel nanocrystals. The key role of atomic-level dispersion of the surface promoter in deN2O is pointed out for the first time.
Title: Direct Decomposition of NO over Co-Mn-Al mixed oxides: effect of Ce or Ce, K promotErs
Authors: Květa Jirátová, Kateřina Pacultová, Kateřina Karásková, Jana Balabánová, Martin Koštejn, and Lucie Obalová
Affiliation: Institute of Chemical Process Fundamentals of the CAS, v.v.i., 165 02 Praha 6, Rozvojová 135, Czech Republic
Abstract: Co–Mn–Al mixed oxides promoted by potassium are known as active catalysts for direct decomposition of nitric oxide (NO). In this study, answer to the following question have been searched: Does presence of cerium in the K-promoted Co–Mn–Al catalysts affect substantially physical-chemical properties, activity, and stability in direct NO decomposition? The Co–Mn–Al, Co-Mn-Al-Ce and Co-Mn-Al-Ce-K mixed oxide catalysts were prepared by the precipitation of corresponding metal nitrates with a solution of Na2CO3/NaOH, followed by the washing of the precipitate, and calcination. Two other catalysts were prepared by impregnation of the Ce-containing catalysts with Co and Co+K nitrates. After calcination, the solids were characterized by chemical analysis, XRD, N2 physisorption, FTIR, temperature programmed reduction, CO2 and O2 desorption (H2-TPR, CO2-TPD, O2-TPD), and X-ray photoelectron spectrometry (XPS). Cerium and especially potassium occurring in the catalysts affected basicity, reducibility, and surface concentration of active components. Adding cerium itself did not contribute to the increase of catalytic activity, whereas adding of cerium and potassium did. Catalytic activity in direct NO decomposition depended on combinations of both reducibility and the amount of stronger basic sites determined in the catalysts. Therefore, the increase of cobalt concentration itself in the Co-Mn-Al mixed oxide catalyst is not determining for achievement of high catalytic activity in direct NO decomposition.