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Catalysts
Special Issues
Selectivity and Stability of Heterogeneous Catalysts
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Selectivity and Stability of Heterogeneous Catalysts

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Catalysis in Organic and Polymer Chemistry".

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 8039

Special Issue Editor

Dr. Jacek Grams

E-Mail Website
Guest Editor
Institute of General and Ecological Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego Street 116, 90-924 Lodz, Poland
Interests: catalysis, synthesis, and characterization of heterogeneous catalysts; biomass conversion; surface characterization of solids; environmental protection; nanotechnology
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The application of heterogeneous catalysts allows for significant increases in the competitiveness and sustainability of numerous industrial processes. One of the most important parameters characterizing the performance of a catalyst is its catalytic activity. However, a high feedstock conversion does not guarantee the formation of desired products. Therefore, besides catalytic activity, we should focus our attention on the improvement of the selectivity of catalytic processes, giving the opportunity to obtain more valuable chemicals. On the other hand, industrial catalysts should be resistant to reaction conditions and work as long as possible. Therefore, we it is also important to ensure their high stability.

Taking that into account, this Special Issue is devoted to the development of new methods for the control of catalyst selectivity and stability of catalysts. This includes the design of new catalysts, modification of the composition of catalysts, development of their synthesis methods, effects of the type of support, the introduction of promoters, the role of the catalyst precursors, the role of contaminants, studies on the relationship between catalytic performance and catalyst physicochemical properties, optimization of reaction conditions, and the impact of reactor type. Moreover, papers in a broad range of related research and application fields other than the main topic are also encouraged.

Prof. Dr. Jacek Grams
Guest Editor

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 submissions that pass pre-check are 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.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • selectivity and stability of heterogeneous catalysts
  • control of catalytic performance
  • catalytic activity
  • synthesis and characterization of catalysts
  • new catalysts
  • modification of the composition of catalysts
  • introduction of promoters and role of catalyst precursors
  • efficiency of catalytic reactions
  • optimization of reaction conditions
  • industrial and environmental catalytic processes

Published Papers (3 papers)

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Research

12 pages, 3751 KiB  
Article
Synthesis of Brominated Alkanes via Heterogeneous Catalytic Distillation over Al2O3/SO42−/ZrO2
by Su Yang, Xiaoxuan Guo, Xiaomei Pan, Liuyu Gu, Xueping Liu, Lijing Gao and Guomin Xiao
Catalysts 2021, 11(12), 1464; https://doi.org/10.3390/catal11121464 - 30 Nov 2021
Cited by 2 | Viewed by 1432
Abstract
Concentrated sulfuric acid is generally used as a catalyst for producing brominated alkanes in traditional methods, but is highly corrosive and difficult to separate. This work reports the preparation of bromopropane from n-propanol based on a reactive distillation strategy combined with alumina-modified sulfated [...] Read more.
Concentrated sulfuric acid is generally used as a catalyst for producing brominated alkanes in traditional methods, but is highly corrosive and difficult to separate. This work reports the preparation of bromopropane from n-propanol based on a reactive distillation strategy combined with alumina-modified sulfated zirconia (Al2O3/SO42−/ZrO2) as a heterogenous catalyst. As expected, under the optimum reaction conditions (110 °C), the yield of bromopropane was 96.18% without side reactions due to the reactive distillation strategy. Meanwhile, the microscopic morphology and performance of Al2O3/SO42−/ZrO2 were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunner–Emmet–Teller (BET), Fourier transform infrared spectroscopy (FT–IR), and other characterization methods. The results confirmed that the morphology of zirconia sulfate is effectively regulated by the modification method of alumina, and more edges and angles provide more catalytic acid sites for the reaction. Furthermore, Al2O3/SO42−/ZrO2 exhibited high stability and remarkable reusability due to the strong chemical bond Zr–Al–Zr. This work provides a practical method for the preparation of bromopropane and can be further extended to the preparation of other bromoalkanes. Full article
(This article belongs to the Special Issue Selectivity and Stability of Heterogeneous Catalysts)
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12 pages, 2079 KiB  
Article
Transition Metal Ions as Ozonation Catalysts: An Alternative Process of Heterogeneous Catalytic Ozonation
by Savvina Psaltou, Konstantina Sioumpoura, Efthimia Kaprara, Manassis Mitrakas and Anastasios Zouboulis
Catalysts 2021, 11(9), 1091; https://doi.org/10.3390/catal11091091 - 10 Sep 2021
Cited by 11 | Viewed by 2213
Abstract
The aim of this study is to elucidate the mechanism of micropollutants’ removal in drinking water by the application of catalytic ozonation, using transition metals as appropriate catalysts. For that purpose, the degradation of 500 μg/L of p-chlorobenzoic acid (p-CBA) and benzotriazole with [...] Read more.
The aim of this study is to elucidate the mechanism of micropollutants’ removal in drinking water by the application of catalytic ozonation, using transition metals as appropriate catalysts. For that purpose, the degradation of 500 μg/L of p-chlorobenzoic acid (p-CBA) and benzotriazole with the addition of 2 mg/L of ozone in the presence of 1 mg/L of Co(II) or Fe(II) and at pH 7.8 were examined. It was found that in distilled water experiments, both metal ions can be characterized as catalysts, enhancing the ozonation process; however, in the natural water matrix, only iron presented higher removal rates of examined organic pollutants, when compared to single ozonation. The metal ions present catalytic activity, when they can form precipitates, hence converting the initially homogeneous process of catalytic ozonation towards a heterogeneous one. However, when 2 mg/L of ozone was applied in natural water experiments, Co(II)—unlike Fe(II)—could not be oxidized into its trivalent form, hence it cannot precipitate as Co(OH)3. Therefore, under these experimental conditions, this metal was not found to present any catalytic activity. Nevertheless, the addition of phosphates (PO43−) in concentrations higher than 100 mg/L can increase the oxidation ability of the Co(II)/O3 system, due to the resulting sufficient formation of Co3(PO4)2 precipitates. Although cobalt can enhance the •OH production (and therefore, the ozonation procedure) under these conditions, the relatively highly added concentration of phosphate ions makes the treated water non-potable, resulting in the application of further treatment to remove the excess phosphates. Therefore, only Fe(II) can be considered as a sufficient catalyst to enhance the ozonation processes. Full article
(This article belongs to the Special Issue Selectivity and Stability of Heterogeneous Catalysts)
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18 pages, 3376 KiB  
Article
Ni-Pd/γ-Al2O3 Catalysts in the Hydrogenation of Levulinic Acid and Hydroxymethylfurfural towards Value Added Chemicals
by Emilia Soszka, Marcin Jędrzejczyk, Ireneusz Kocemba, Nicolas Keller and Agnieszka M. Ruppert
Catalysts 2020, 10(9), 1026; https://doi.org/10.3390/catal10091026 - 07 Sep 2020
Cited by 14 | Viewed by 2888
Abstract
γ-Al2O3 supported Ni-Pd catalysts with different Ni:Pd ratios were studied in the hydrogenation of two industrially-relevant platform molecules derived from biomass, namely levulinic acid and hydroxymethylfurfural. The bimetallic catalysts showed better performances in both processes in comparison to the monometallic [...] Read more.
γ-Al2O3 supported Ni-Pd catalysts with different Ni:Pd ratios were studied in the hydrogenation of two industrially-relevant platform molecules derived from biomass, namely levulinic acid and hydroxymethylfurfural. The bimetallic catalysts showed better performances in both processes in comparison to the monometallic counterparts, for which a too strong interaction with the alumina support reduced the activity. The behavior of the bimetallic catalysts was dependent on the Ni:Pd ratio, and interestingly also on the targeted hydrogenation reaction. The Pd-modified Ni-rich system behaves like pure Ni catalyst, but with a strongly boosted activity due to a higher number of Ni active sites available, Pd being considered as a spectator. This high activity was manifested in the levulinic acid hydrogenation with formic acid used as an internal hydrogen source. This behavior differs from the case of the Pd-rich system modified by Ni, which displayed a much higher Pd dispersion on the support compared to the monometallic Pd catalyst. The higher availability of the Pd active sites while maintaining a high surface acidity allows the catalyst to push the HMF hydrodeoxygenation reaction forward towards the green biopolymer precursor 2,5-bis(hydroxymethyl)-tetrahydrofuran, and in consequence to strongly modify the selectivity of the reaction. In that case, residual chlorine was proposed to play a significant role, while Ni was considered as a spectator. Full article
(This article belongs to the Special Issue Selectivity and Stability of Heterogeneous Catalysts)
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