Topic Editors

Dr. Maria Luisa Di Gioia
Dipartimento di Farmacia e Scienze della Salute e della Nutrizione, Edificio Polifunzionale, Università della Calabria, 87036 Rende, CS, Italy
Prof. Dr. Luísa Margarida Martins
Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
Dr. Isidro M. Pastor
Departamento de Química Orgánica, Facultad de Ciencias and Instituto de Síntesis Orgánica (ISO), Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain

Catalysis: Homogeneous and Heterogeneous

Abstract submission deadline
30 June 2023
Manuscript submission deadline
31 August 2023
Viewed by
20620

Topic Information

Dear Colleagues,

Chemistry has a remarkable ability to transform naturally occurring materials into new materials, with new properties and performances that would not otherwise exist. However, only chemical innovations conducted sustainably can allow progress towards achieving the United Nations Sustainable Development Goals.

Catalysis (both homogeneous and heterogeneous) is a remarkably important tool to aid towards innovation for sustainable development, enabling reactions to be performed with the highest energy saving, in the most efficient, economical, and environmentally responsible way. This Topic is devoted to the fundamental and applied aspects of catalysis, with the aim of providing a comprehensive perspective on the current status of the research field. It is expected that this will help to provide a bridge between the most fundamental knowledge on homo- and heterogeneous catalytic systems and the development of new applications based on this knowledge.

Dr. Maria Luisa Di Gioia
Prof. Dr. Luísa Margarida Martins
Dr. Isidro M. Pastor
Topic Editors

Keywords

  • homogeneous catalysis
  • heterogeneous catalysis
  • biocatalysis
  • electrocatalysis
  • nanocatalysis
  • catalyst selectivity
  • catalyst activity
  • catalysis in green chemistry
  • organocatalysis

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Catalysts
catalysts
4.501 5.5 2011 13 Days 2200 CHF Submit
Chemistry
chemistry
- - 2019 16.1 Days 1400 CHF Submit
Materials
materials
3.748 4.7 2008 15.3 Days 2300 CHF Submit
Molbank
molbank
- 0.8 1997 13.2 Days 500 CHF Submit
Molecules
molecules
4.927 5.9 1996 14.2 Days 2300 CHF Submit

Preprints is a platform dedicated to making early versions of research outputs permanently available and citable. MDPI journals allow posting on preprint servers such as Preprints.org prior to publication. For more details about reprints, please visit https://www.preprints.org.

Published Papers (26 papers)

Order results
Result details
Journals
Select all
Export citation of selected articles as:
Short Note
8,13-Dimethylicosa-9,11-diyne-8,13-diol
Molbank 2022, 2022(4), M1484; https://doi.org/10.3390/M1484 - 07 Nov 2022
Abstract
The protocol, 3-methyldec-1-yn-3-ol (1a) was chosen to perform the dimerization process. The optimal conditions for synthesis of 8,13-dimethylicosa-9,11-diyne-8,13 (2a) with high efficiency when using copper-catalyzed, N,N,N′N′-tetramethylethylenediamine as a ligand and CCl4 and methanol solvents in atmospheric pressure were [...] Read more.
The protocol, 3-methyldec-1-yn-3-ol (1a) was chosen to perform the dimerization process. The optimal conditions for synthesis of 8,13-dimethylicosa-9,11-diyne-8,13 (2a) with high efficiency when using copper-catalyzed, N,N,N′N′-tetramethylethylenediamine as a ligand and CCl4 and methanol solvents in atmospheric pressure were determined. The structure of the obtained compound was proved by IR, 1H-NMR and 13C-NMR spectroscopy. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Scheme 1

Article
In Situ X-ray Absorption Spectroscopy Cells for High Pressure Homogeneous Catalysis
Catalysts 2022, 12(10), 1264; https://doi.org/10.3390/catal12101264 - 17 Oct 2022
Abstract
We have designed, built, and tested two cells for in situ and, potentially, operando X-ray absorption spectroscopy experiments in transmission and fluorescence modes. The cells were developed for high-pressure and high-temperature conditions to study the catalytic processes under relevant industrial conditions. Operation of [...] Read more.
We have designed, built, and tested two cells for in situ and, potentially, operando X-ray absorption spectroscopy experiments in transmission and fluorescence modes. The cells were developed for high-pressure and high-temperature conditions to study the catalytic processes under relevant industrial conditions. Operation of the cells was tested for Ru and Rh-based homogeneous and heterogeneous catalytic systems. Using synchrotron-based in situ X-ray absorption spectroscopy we tracked the evolution of active metal species during catalytic reactions. Our setup proved that it was capable to investigate liquid-state homogeneous and heterogenous systems under elevated temperatures, high pressures of reactive gasses, and in the presence of corrosive reagents. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
Investigation of a Complex Reaction Pathway Network of Isobutane/2-Butene Alkylation by CGC–FID and CGC-MS-DS
Molecules 2022, 27(20), 6866; https://doi.org/10.3390/molecules27206866 - 13 Oct 2022
Abstract
The mechanism of reaction in isobutane/2-butene alkylation systems is extremely complicated, accompanied by numerous side reactions. Therefore, a comprehensive understanding of the reaction pathways in this system is essential for an in-depth discussion of the reaction mechanism and for improving the selectivity of [...] Read more.
The mechanism of reaction in isobutane/2-butene alkylation systems is extremely complicated, accompanied by numerous side reactions. Therefore, a comprehensive understanding of the reaction pathways in this system is essential for an in-depth discussion of the reaction mechanism and for improving the selectivity of the major products (clean fuel blend components). The alkylation of isobutane/2-butene was studied using a self-made intermittent reaction device with a metering, cooling, reaction, vacuum and analysis system. The alkylates were qualitatively and quantitatively analyzed using a capillary gas chromatography-mass spectrometry-data system (CGC-MS-DS) and capillary gas chromatography with flame ionization detection (CCGC-FID), respectively, and the precision and recovery of the quantitative analytical methods were verified. The results showed that the relative standard deviation (RSD) of the standard sample was below 0.78%, and the recoveries were from 98.53% to 102.85%. Under the specified reaction conditions, 79 volatile substances were identified from the alkylates, and the selectivity of C8 and trimethylpentanes (TMPs) reached 63.63% and 53.81%, respectively. The changes of the main chemical components in the alkylation reaction with time were tracked and analyzed, based on which reaction pathways were determined, and a complex reaction network containing the main products’ and the by-products’ generation pathway was constructed. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
Polymer-Supported Poly(Ethylene Glycol) as a Phase-Transfer Catalyst for Cross-Aldol Condensation of Isobutyroaldehyde and Formaldehyde
Molecules 2022, 27(19), 6459; https://doi.org/10.3390/molecules27196459 - 30 Sep 2022
Abstract
Immobilized poly(ethylene glycol) (PEG 600-PS) was used as an effective phase-transfer catalyst for the synthesis of hydroxypivaldehyde from isobutyraldehyde (IBA) and formaldehyde in the presence of an inorganic base. Studies on the influence of the parameters on the course of the reaction in [...] Read more.
Immobilized poly(ethylene glycol) (PEG 600-PS) was used as an effective phase-transfer catalyst for the synthesis of hydroxypivaldehyde from isobutyraldehyde (IBA) and formaldehyde in the presence of an inorganic base. Studies on the influence of the parameters on the course of the reaction in a batch reactor showed that the use of the PEG 600-PS catalyst allowed one to obtain HPA with high efficiency (IBA conversion >96%, selectivity >98%) in a relatively short time and under mild conditions (2 h, 40 °C). The developed method enables easy separation of the post-reaction mixture by simple phase separation, and the immobilized catalyst can be separated by filtration and then used five times without a loss in its activity. The high activity and stability of the catalyst was also confirmed in a test carried out in a flow reactor. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Graphical abstract

Short Note
Bis(2-hydroxyethyl) 2-phenylsuccinate
Molbank 2022, 2022(4), M1456; https://doi.org/10.3390/M1456 - 26 Sep 2022
Abstract
Succinic acid esters are important compounds that find many applications in various industrial fields. One of the most promising and easy ways of producing these molecules is represented by the bis-alkoxycarbonylation reaction of olefins. In particular, a recently developed catalytic system, consisting of [...] Read more.
Succinic acid esters are important compounds that find many applications in various industrial fields. One of the most promising and easy ways of producing these molecules is represented by the bis-alkoxycarbonylation reaction of olefins. In particular, a recently developed catalytic system, consisting of an aryl α-diimine/palladium(II) catalyst and p-benzoquinone as an oxidant, has allowed succinates to be obtained in high yields. A similar methodology was applied here for the unprecedented synthesis of the bis(2-hydroxyethyl) 2-phenylsuccinate in 78% isolated yield, starting from the cheap and commercially available compounds styrene and ethylene glycol. To our knowledge, no other examples of bis-alkoxycarbonylations of olefins involving diols have been reported thus far. The obtained product was fully characterized by NMR and ESI-MS analyses. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Scheme 1

Article
Non-Oxidative Propane Dehydrogenation on CrOx-ZrO2-SiO2 Catalyst Prepared by One-Pot Template-Assisted Method
Molecules 2022, 27(18), 6095; https://doi.org/10.3390/molecules27186095 - 18 Sep 2022
Cited by 1
Abstract
A series of CrOx-ZrO2-SiO2 (CrZrSi) catalysts was prepared by a “one-pot” template-assisted evaporation-induced self-assembly process. The chromium content varied from 4 to 9 wt.% assuming Cr2O3 stoichiometry. The catalysts were characterized by XRD, SEM-EDX, temperature-programmed [...] Read more.
A series of CrOx-ZrO2-SiO2 (CrZrSi) catalysts was prepared by a “one-pot” template-assisted evaporation-induced self-assembly process. The chromium content varied from 4 to 9 wt.% assuming Cr2O3 stoichiometry. The catalysts were characterized by XRD, SEM-EDX, temperature-programmed reduction (TPR-H2), Raman spectroscopy, and X-ray photoelectron spectroscopy. The catalysts were tested in non-oxidative propane dehydrogenation at 500–600 °C. The evolution of active sites under the reaction conditions was investigated by reductive treatment of the catalysts with H2. The catalyst with the lowest Cr loading initially contained amorphous Cr3+ and dispersed Cr6+ species. The latter reduced under reaction conditions forming Cr3+ oxide species with low activity in propane dehydrogenation. The catalysts with higher Cr loadings initially contained highly dispersed Cr3+ species stable under the reaction conditions and responsible for high catalyst activity. Silica acted both as a textural promoter that increased the specific surface area of the catalysts and as a stabilizer that inhibited crystallization of Cr2O3 and ZrO2 and provided the formation of coordinatively unsaturated Zr4+ centers. The optimal combination of Cr3+ species and coordinatively unsaturated Zr4+ centers was achieved in the catalyst with the highest Cr loading. This catalyst showed the highest efficiency. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Graphical abstract

Article
Fast Initiating Furan-Containing Hoveyda-Type Complexes: Synthesis and Applications in Metathesis Reactions
Chemistry 2022, 4(3), 786-795; https://doi.org/10.3390/chemistry4030056 - 09 Aug 2022
Abstract
Two new ruthenium complexes with chelating-ether benzylidene ligands bearing a furan moiety were synthesized and characterized, including X-ray crystallography. They initiated fast, also at 0 °C, and were found to be highly active in a variety of ring-closing, ene-yne, and cross-metathesis reactions, including [...] Read more.
Two new ruthenium complexes with chelating-ether benzylidene ligands bearing a furan moiety were synthesized and characterized, including X-ray crystallography. They initiated fast, also at 0 °C, and were found to be highly active in a variety of ring-closing, ene-yne, and cross-metathesis reactions, including an active pharmaceutical ingredient (API) model, which makes them good candidates for the transformation of complex polyfunctional compounds that require mild reaction conditions. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
Mechanistic Insights into Palladium(II)-Catalyzed Carboxylation of Thiophene and Carbon Dioxide
Catalysts 2022, 12(6), 654; https://doi.org/10.3390/catal12060654 - 15 Jun 2022
Abstract
The mechanism in palladium-catalyzed carboxylation of thiophene and CO2 is investigated using the density functional theory (DFT) calculations, including three consecutive steps of the formation of carbanion through breaking the C–H bond(s) via the palladium acetate, the elimination of acetic acid and [...] Read more.
The mechanism in palladium-catalyzed carboxylation of thiophene and CO2 is investigated using the density functional theory (DFT) calculations, including three consecutive steps of the formation of carbanion through breaking the C–H bond(s) via the palladium acetate, the elimination of acetic acid and the nucleophile attacking the weak electrophile CO2 to form C–C bond. Results show that the C–C bond is formed through taking the three-membered cyclic conformation arrangement involving the interaction of the transition metal and the CO2, and the CO2 insertion step is the rate-determining step for this entire reaction process. Aiming to precisely disclose what factor determine the origin of the activation energy barrier in this carboxylation reaction, the distortion/interaction analysis is performed along with the entire reaction coordinate. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
Modification of the Acidic and Textural Properties of HY Zeolite by AHFS Treatment and Its Coke Formation Performance in the Catalytic Cracking Reaction of N-Butene
Catalysts 2022, 12(6), 640; https://doi.org/10.3390/catal12060640 - 11 Jun 2022
Abstract
Coke formation on n-butene cracking catalyst is the main reason for the reducing of its lifetime. To study the effects of acidity and textural properties on the coke formation process, a series of HY zeolite-type catalysts were prepared by ammonium hexafluorosilicate treatment (AHFS). [...] Read more.
Coke formation on n-butene cracking catalyst is the main reason for the reducing of its lifetime. To study the effects of acidity and textural properties on the coke formation process, a series of HY zeolite-type catalysts were prepared by ammonium hexafluorosilicate treatment (AHFS). NH3-TPD and Py-IR-TPD were used to systematically study the change law of zeolite acidity. It was found that with the increase of AHFS concentration, the acid density decreased, whereas the ratio of Brønsted acid to Lewis acid first increased and then decreased. Meanwhile, the percentage of Brønsted acid inside the supper cages increased and the strength of Brønsted acid increased with the degree of dealumination. Combined with in situ IR study on coke formation, the relationship between coking and acid site was revealed. It was found that the rate of coke formation on zeolites was affected by acid density, which is the rate of coke formation decreased with the decline of acid density. When the acid density remains at the same level, it was the acid strength that determined the coke formation rate—the stronger the acid strength, the faster the coke formation rate. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
Enhanced Catalytic Oxidation of Toluene over Hierarchical Pt/Y Zeolite
Catalysts 2022, 12(6), 622; https://doi.org/10.3390/catal12060622 - 06 Jun 2022
Cited by 1
Abstract
The development of efficient Pt-supported zeolite catalysts with tunable micro/mesopore structures for the removal of volatile organic compounds (VOCs) presents a major challenge. Herein, hierarchical Pt/Y zeolites with tunable mesopores are fabricated by varying the etching time before the surfactant-templated crystal rearrangement method [...] Read more.
The development of efficient Pt-supported zeolite catalysts with tunable micro/mesopore structures for the removal of volatile organic compounds (VOCs) presents a major challenge. Herein, hierarchical Pt/Y zeolites with tunable mesopores are fabricated by varying the etching time before the surfactant-templated crystal rearrangement method and used as catalyst supports for VOC oxidation. The hierarchical Pt/Y zeolites provided an excellent environment for Pt nanoparticle loading with abundant accessible acidic sites. The catalytic performance of the obtained hierarchical Pt/Y zeolites is analyzed using toluene oxidation, with the modified zeolites exhibiting improved catalytic activities. The hierarchical Pt/Y zeolites exhibited higher catalytic toluene oxidation activities than non-hierarchical Pt/Y zeolites. Pt/Y-6h demonstrated the highest catalytic toluene oxidation activity of the prepared catalysts, with a T90 of 149 °C, reaction rate of 1.15 × 10−7 mol gcat−1 s−1, turnover frequency of 1.20 × 10−2 s−1, and an apparent activation energy of 66.5 kJ mol−1 at 60,000 mL g−1 h−1 at a toluene concentration of 1000 ppm. This study will facilitate the fine-tuning of hierarchically porous materials to improve material properties and achieve higher catalytic performance toward VOC oxidation. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Graphical abstract

Review
Recent Achievements in the Synthesis of Cyclic Carbonates from Olefins and CO2: The Rational Design of the Homogeneous and Heterogeneous Catalytic System
Catalysts 2022, 12(5), 563; https://doi.org/10.3390/catal12050563 - 20 May 2022
Abstract
With the consumption of fossil fuels, the level of CO2 in the atmosphere is growing rapidly, which leads to global warming. Hence, the chemical conversion of CO2 into high value-added products is one of the most important approaches to reducing CO [...] Read more.
With the consumption of fossil fuels, the level of CO2 in the atmosphere is growing rapidly, which leads to global warming. Hence, the chemical conversion of CO2 into high value-added products is one of the most important approaches to reducing CO2 emissions. Due to being simple, inexpensive and environmentally friendly, the direct synthesis of cyclic carbonates from olefins and CO2 is a promising project for industrial application. In this review, we discuss the design of the homogeneous and heterogeneous catalytic system for the synthesis of cyclic carbonates from the reaction of olefins and CO2. Usually, the catalyst contains the epoxidation active site and the cycloaddition active site, which could achieve the oxidation of oleifins and the CO2-insert, respectively. This review will provide a comprehensive overview of the direct synthesis of cyclic carbonates from olefins and CO2 catalyzed by homogeneous and heterogeneous catalysts. The focus mainly lies on the rational fabrication of multifunctional catalysts, and provides a new perspective for the design of catalysts. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Scheme 1

Review
A Photocatalytic Hydrolysis and Degradation of Toxic Dyes by Using Plasmonic Metal–Semiconductor Heterostructures: A Review
Chemistry 2022, 4(2), 454-479; https://doi.org/10.3390/chemistry4020034 - 15 May 2022
Cited by 1
Abstract
Converting solar energy to chemical energy through a photocatalytic reaction is an efficient technique for obtaining a clean and affordable source of energy. The main problem with solar photocatalysts is the recombination of charge carriers and the large band gap of the photocatalysts. [...] Read more.
Converting solar energy to chemical energy through a photocatalytic reaction is an efficient technique for obtaining a clean and affordable source of energy. The main problem with solar photocatalysts is the recombination of charge carriers and the large band gap of the photocatalysts. The plasmonic noble metal coupled with a semiconductor can give a unique synergetic effect and has emerged as the leading material for the photocatalytic reaction. The LSPR generation by these kinds of materials has proved to be very efficient in the photocatalytic hydrolysis of the hydrogen-rich compound, photocatalytic water splitting, and photocatalytic degradation of organic dyes. A noble metal coupled with a low bandgap semiconductor result in an ideal photocatalyst. Here, both the noble metal and semiconductor can absorb visible light. They tend to produce an electron–hole pair and prevent the recombination of the generated electron–hole pair, which ultimately reacts with the chemicals in the surrounding area, resulting in an enhanced photocatalytic reaction. The enhanced photocatalytic activity credit could be given to the shared effect of the strong SPR and the effective separation of photogenerated electrons and holes supported by noble metal particles. The study of plasmonic metal nanoparticles onto semiconductors has recently accelerated. It has emerged as a favourable technique to master the constraint of traditional photocatalysts and stimulate photocatalytic activity. This review work focuses on three main objectives: providing a brief explanation of plasmonic dynamics, understanding the synthesis procedure and examining the main features of the plasmonic metal nanostructure that dominate its photocatalytic activity, comparing the reported literature of some plasmonic photocatalysts on the hydrolysis of ammonia borane and dye water treatment, providing a detailed description of the four primary operations of the plasmonic energy transfer, and the study of prospects and future of plasmonic nanostructures. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
Catalytic Performance of One-Pot Synthesized Fe-MWW Layered Zeolites (MCM-22, MCM-36, and ITQ-2) in Selective Catalytic Reduction of Nitrogen Oxides with Ammonia
Molecules 2022, 27(9), 2983; https://doi.org/10.3390/molecules27092983 - 06 May 2022
Cited by 2
Abstract
The application of layered zeolites of MWW topology in environmental catalysis has attracted growing attention in recent years; however, only a few studies have explored their performance in selective catalytic reduction with ammonia (NH3-SCR). Thus, our work describes, for the first [...] Read more.
The application of layered zeolites of MWW topology in environmental catalysis has attracted growing attention in recent years; however, only a few studies have explored their performance in selective catalytic reduction with ammonia (NH3-SCR). Thus, our work describes, for the first time, the one-pot synthesis of Fe-modified NH3-SCR catalysts supported on MCM-22, MCM-36, and ITQ-2. The calculated chemical composition of the materials was Si/Al of 30 and 5 wt.% of Fe. The reported results indicated a correlation between the arrangement of MWW layers and the form of iron in the zeolitic structure. We have observed that one-pot synthesis resulted in high dispersion of Fe3+ sites, which significantly enhanced low-temperature activity and prevented N2O generation during the reaction. All of the investigated samples exhibited almost 100% NO conversion at 250 °C. The most satisfactory activity was exhibited by Fe-modified MCM-36, since 50% of NO reduction was obtained at 150 °C for this catalyst. This effect can be explained by the abundance of isolated Fe3+ species, which are active in low-temperature NH3-SCR. Additionally, SiO2 pillars present in MCM-36 provided an additional surface for the deposition of the active phase. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
Cu-Y2O3 Catalyst Derived from Cu2Y2O5 Perovskite for Water Gas Shift Reaction: The Effect of Reduction Temperature
Catalysts 2022, 12(5), 481; https://doi.org/10.3390/catal12050481 - 25 Apr 2022
Abstract
Cu2Y2O5 perovskite was reduced at different temperatures under H2 atmosphere to prepare two Cu-Y2O3 catalysts. The results of the activity test indicated that the Cu-Y2O3 catalyst after H2-reduction at [...] Read more.
Cu2Y2O5 perovskite was reduced at different temperatures under H2 atmosphere to prepare two Cu-Y2O3 catalysts. The results of the activity test indicated that the Cu-Y2O3 catalyst after H2-reduction at 500 °C (RCYO-500) exhibited the best performance in the temperature range from 100 to 180 °C for water gas shift (WGS) reaction, with a CO conversion of 57.30% and H2 production of 30.67 μmol·gcat−1·min−1 at 160 °C and a gas hourly space velocity (GHSV) of 6000 mL·gcat−1·h−1. The catalyst reduced at 320 °C (RCYO-320) performed best at the temperature range from 180 to 250 °C, which achieved 86.44% CO conversion and 54.73 μmol·gcat−1·min−1 H2 production at 250 °C. Both of the Cu-Y2O3 catalysts had similar structures including Cu°, Cu+, oxygen vacancies (Vo) on the Cu°-Cu+ interface and Y2O3 support. RCYO-500, with a mainly exposed Cu° (100) facet, was active in the low-temperature WGS reaction, while the WGS activity of RCYO-320, which mainly exposed the Cu° (111) facet, was greatly enhanced above 180 °C. Different Cu° facets have different abilities to absorb H2O and then dissociate it to form hydroxyl groups, which is the main step affecting the catalytic rate of the WGS reaction. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
Enantioselective Organocatalyzed Michael Addition of Isobutyraldehyde to Maleimides in Aqueous Media
Molecules 2022, 27(9), 2759; https://doi.org/10.3390/molecules27092759 - 25 Apr 2022
Abstract
Thiourea was introduced into (R,R)-1,2-diphenylethylenediamine as an organocatalyst to promote the reaction between isobutyraldehydes and maleimides. Enantioselective Michael addition reaction was carried out as an eco-friendly method using water as the solvent. As a result of the reaction between isobutyraldehyde [...] Read more.
Thiourea was introduced into (R,R)-1,2-diphenylethylenediamine as an organocatalyst to promote the reaction between isobutyraldehydes and maleimides. Enantioselective Michael addition reaction was carried out as an eco-friendly method using water as the solvent. As a result of the reaction between isobutyraldehyde and maleimide, ≥97% yield and 99% enantioselectivity were obtained at a low catalyst loading of 0.01 mol%. The solvent effect can be explained by theoretical calculations that indicate the participation of a transition state, in which the CF3 substituent of the catalyst is a hydrogen bond activated by the surrounding water molecules. This discovery enabled the use of low catalyst loading in the organic reactions of chiral substances for pharmaceutical applications. Furthermore, a solvent effect for Michael reaction of the organocatalysts was proposed, and the organic reaction mechanisms were determined through quantum calculations. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
Effect of Ceria Doping in Different Impregnation Steps on Ni-Based Catalysts Loading on TiO2-SiC for CO Methanation
Catalysts 2022, 12(4), 429; https://doi.org/10.3390/catal12040429 - 11 Apr 2022
Abstract
A series of TiO2-SiC supported Ni-based catalysts with and without ceria doping were prepared by a traditional impregnation method. CeO2 was introduced into the catalyst in different steps of the impregnation process. All the samples were characterized by N2 [...] Read more.
A series of TiO2-SiC supported Ni-based catalysts with and without ceria doping were prepared by a traditional impregnation method. CeO2 was introduced into the catalyst in different steps of the impregnation process. All the samples were characterized by N2 physisorption, XRD, TPR, and TGA, and were tested for the performance of CO methanation in a fixed-bed reactor under atmospheric conditions through the steam of H2/CO = 3 without diluent gas. All the Ni-based catalysts supported by TiO2-SiC exhibited the property of anti-sintering and could efficiently avoid carbon deposition occurring on catalysts. The experimental results show that the performance of all CeO2 doping samples (more than 80% of CO conversion) was better than the sample without CeO2 (around 20% of CO conversion). Introducing CeO2 after the dry step of impregnation achieved complete CO conversion at a lower temperature compared with its introduction through doping at the co-impregnation and step-impregnation methods. The results of further characterization indicate that the addition of CeO2 in different impregnation steps affected the dispersion of nickel on support, made the size of metal particles smaller, and changed the reducibility of catalysts. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Communication
Enhanced Photocatalytic Oxidation of RhB and MB Using Plasmonic Performance of Ag Deposited on Bi2WO6
Chemistry 2022, 4(2), 272-296; https://doi.org/10.3390/chemistry4020022 - 06 Apr 2022
Cited by 4
Abstract
Visible-light-driven heterostructure Ag/Bi2WO6 nanocomposites were prepared using a hydrothermal method followed by the photodeposition of Ag on Bi2WO6. A photocatalyst with a different molar ratio of Ag to Bi2WO6 (1:1, 1:2 and 2:1) [...] Read more.
Visible-light-driven heterostructure Ag/Bi2WO6 nanocomposites were prepared using a hydrothermal method followed by the photodeposition of Ag on Bi2WO6. A photocatalyst with a different molar ratio of Ag to Bi2WO6 (1:1, 1:2 and 2:1) was prepared. The catalytic performance of Ag/Bi2WO6 towards the photocatalytic oxidation of rhodamine B (RhB) and methylene blue (MB) was explored. Interestingly, the Ag/Bi2WO6 (1:2) catalyst exhibited superior performance; it oxidized 83% of RhB to Rh-110 and degraded 68% of MB in 90 min. This might be due to the optimum amount of Ag nanoparticles, which supported the rapid generation and transfer of separated charges from Bi2WO6 to Ag through the Schottky barrier. An excess of Ag on Bi2WO6 (1:1 and 2:1) blocked the active sites of the reaction and did not produce the desired result. The introduction of Ag on Bi2WO6 improved the electrical conductivity of the composite and lowered the recombination rate of charge carriers. Our work provides a cost-effective route for constructing high-performance catalysts for the degradation of toxic dyes. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
Non-Covalent Functionalization of Graphene Oxide-Supported 2-Picolyamine-Based Zinc(II) Complexes as Novel Electrocatalysts for Hydrogen Production
Catalysts 2022, 12(4), 389; https://doi.org/10.3390/catal12040389 - 31 Mar 2022
Cited by 1
Abstract
Three mononuclear 2-picolylamine-containing zinc(III) complexes viz [(2-PA)2ZnCl]2(ZnCl4)] (Zn1), [(2-PA)2Zn(H2O)](NO3)2] (Zn2) and [Zn(2-PA)2(OH)]NO3] (Zn3) were synthesized and fully characterized. Spectral [...] Read more.
Three mononuclear 2-picolylamine-containing zinc(III) complexes viz [(2-PA)2ZnCl]2(ZnCl4)] (Zn1), [(2-PA)2Zn(H2O)](NO3)2] (Zn2) and [Zn(2-PA)2(OH)]NO3] (Zn3) were synthesized and fully characterized. Spectral and X-ray structural characteristics showed that the Zn1 complex has a square-pyramidal coordination environment around a zinc(II) core. The hydroxide complex Zn3 was non-covalently functionalized with few layers of graphene oxide (GO) sheets, formed by exfoliation of GO in water. The resulting Zn3/GO hybrid material was characterized by FT-IR, TGA-DSC, SEM-EDX and X-ray powder diffraction. The way of interaction of Zn3 with GO has been established through density functional theory (DFT) calculations. Both experimental and theoretical findings indicate that, on the surface of GO, the complex Zn3 forms a complete double-sided adsorption layer. Zn3 and its hybrid form Zn3/GO have been individually investigated as electrocatalysts for the hydrogen evolution reaction. The hybrid heterogenized form Zn3/GO was supported on glassy carbon (GC) with variable loading densities of Zn3 (0.2, 0.4 and 0.8 mg cm−2) to form electrodes. These electrodes have been tested as molecular electrocatalysts for the hydrogen evolution reaction (HER) using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in 0.1 M KOH. Results showed that both GC-Zn3 and GC-Zn3/GO catalysts for the HER are highly active, and with increase of the catalyst’s loading density, this catalytic activity enhances. The high catalytic activity of HER with a low onset potential of −140 mV vs. RHE and a high exchange current density of 0.22 mA cm−2 is achieved with the highest loading density of Zn3 (0.8 mg cm−2). To achieve a current density of 10 mA cm−2, an overpotential of 240 mV was needed. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
Role of the Hydroxyl Groups Coordinated toTiO2 Surface on the Photocatalytic Decomposition of Ethylene at Different Ambient Conditions
Catalysts 2022, 12(4), 386; https://doi.org/10.3390/catal12040386 - 30 Mar 2022
Cited by 2
Abstract
The titania pulp—a semi product received from the industrial production of titania white—was submitted for the thermal heating at 400–600 °C under Ar and H2 to obtain TiO2 with different structure and oxygen surface defects. Heating of titania in H2 [...] Read more.
The titania pulp—a semi product received from the industrial production of titania white—was submitted for the thermal heating at 400–600 °C under Ar and H2 to obtain TiO2 with different structure and oxygen surface defects. Heating of titania in H2 atmosphere accelerated dehydration and crystallisation of TiO2 compared to heating in Ar. TiO2 prepared at 500 and 600 °C under H2 had some oxygen vacancies and Ti3+ centres (electron traps), whereas TiO2 obtained at 450 °C under H2 exhibited some hole traps centres. The presence of oxygen vacancies induced adsorption of atmospheric CO2. It was evidenced, that ethylene reacted with TiO2 after UV irradiation. Formic acid was identified on TiO2 surface as the reaction product of ethylene oxidation. Hydroxyl radicals were involved in complete mineralisation of ethylene. TiO2 prepared at 500 °C under H2 was poorly active because some active sites for coordination of ethylene molecules were occupied by CO2. The most active samples were TiO2 with high quantity of OH terminal groups. At 50 °C, the physically adsorbed water molecules on titania surface were desorbed, and then photocatalytic decomposition of ethylene was more efficient. TiO2 with high quantity of chemisorbed OH groups was very active for ethylene decomposition. The acidic surface of TiO2 enhances its hydroxylation. Therefore, it is stated that TiO2 having acidic active sites can be an excellent photocatalyst for ethylene decomposition under UV light. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Graphical abstract

Article
Dispersion and Stabilization of Supported Layered Double Hydroxide-Based Nanocomposites on V-Based Catalysts for Nonoxidative Dehydrogenation of Isobutane to Isobutene
Catalysts 2022, 12(4), 382; https://doi.org/10.3390/catal12040382 - 29 Mar 2022
Cited by 1
Abstract
Nonoxidative dehydrogenation of isobutane is one of the sustainable strategies for producing high value added isobutene. As alternatives for the commercial Pt- and Cr-based dehydrogenation catalysts, supported V-based catalysts are worthy of study. In this work, a series of VOx/mMgAlO-R catalysts [...] Read more.
Nonoxidative dehydrogenation of isobutane is one of the sustainable strategies for producing high value added isobutene. As alternatives for the commercial Pt- and Cr-based dehydrogenation catalysts, supported V-based catalysts are worthy of study. In this work, a series of VOx/mMgAlO-R catalysts (m = 10, 15, 20, 25 and 30) were designed and prepared by loading VOx on mMgAlO composite oxide supports derived from mesoporous Al2O3-supported layered double hydroxide (LDH) nanocomposites. The calcined and reduced catalysts were characterized by X-ray diffraction (XRD), Raman spectra, Ultraviolet-visible diffuse reflectance (UV-Vis) spectra, NH3 temperature-programmed desorption (NH3-TPD), Temperature-programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TG) and low temperature N2 adsorption–desorption isotherms. The as-synthesized VOx/20MgAlO-R with appropriate Mg addition exhibits superior activity (43–56% conversion and 77–81% selectivity), excellent stability and coking-resistance for the isobutane dehydrogenation. The structure–performance relationship reveals that the formation of VOx species confined in the reconstructed LDH interlayer and porous MgO facilitates dispersing and stabilizing the VOx species. The low polymerization degree and higher proportion of V4+ ion for VOx species, strong acidity of medium acid sites and low concentration of strong acid sites are responsible for the excellent anti-coking and catalytic performance. The strong VOx–support interaction is beneficial for enhancing the stability of the catalysts. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Graphical abstract

Article
Fabrication and Characterization of Highly Efficient As-Synthesized WO3/Graphitic-C3N4 Nanocomposite for Photocatalytic Degradation of Organic Compounds
Materials 2022, 15(7), 2482; https://doi.org/10.3390/ma15072482 - 28 Mar 2022
Cited by 2
Abstract
The incorporation of tungsten trioxide (WO3) by various concentrations of graphitic carbon nitride (g-C3N4) was successfully studied. X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and Diffused Reflectance UV-Vis techniques were applied to investigate morphological and microstructure analysis, [...] Read more.
The incorporation of tungsten trioxide (WO3) by various concentrations of graphitic carbon nitride (g-C3N4) was successfully studied. X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and Diffused Reflectance UV-Vis techniques were applied to investigate morphological and microstructure analysis, diffused reflectance optical properties, and photocatalysis measurements of WO3/g-C3N4 photocatalyst composite organic compounds. The photocatalytic activity of incorporating WO3 into g-C3N4 composite organic compounds was evaluated by the photodegradation of both Methylene Blue (MB) dye and phenol under visible-light irradiation. Due to the high purity of the studied heterojunction composite series, no observed diffraction peaks appeared when incorporating WO3 into g-C3N4 composite organic compounds. The particle size of the prepared composite organic compound photocatalysts revealed no evident influence through the increase in WO3 atoms from the SEM characteristic. The direct and indirect bandgap were recorded for different mole ratios of WO3/g-C3N4, and indicated no apparent impact on bandgap energy with increasing WO3 content in the composite photocatalyst. The composite photocatalysts’ properties better understand their photocatalytic activity degradations. The pseudo-first-order reaction constants (K) can be calculated by examining the kinetic photocatalytic activity. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
The Zr Modified γ-Al2O3 Catalysts for Stable Hydrolytic Decomposition of CF4 at Low Temperature
Catalysts 2022, 12(3), 313; https://doi.org/10.3390/catal12030313 - 09 Mar 2022
Cited by 2
Abstract
CF4, one of the Perfluorocompounds (PFCs), also known as a greenhouse gas with high global warming potential. In this study, Zr/γ-Al2O3 catalysts were developed for CF4 decomposition. The addition of Zr onto γ-Al2O3 achieves [...] Read more.
CF4, one of the Perfluorocompounds (PFCs), also known as a greenhouse gas with high global warming potential. In this study, Zr/γ-Al2O3 catalysts were developed for CF4 decomposition. The addition of Zr onto γ-Al2O3 achieves a high CF4 conversion efficiency of 85% at 650 °C and maintain its activity for more than 60 h, which is obviously higher than that of bare γ-Al2O3 (50%). The mechanism involved in CF4 decomposition over the Zr/γ-Al2O3 are clarified that the surface Lewis acidity sites are the main active center for CF4 directly adsorbing and decomposing. The results of NH3-TPD and FT-IR analyses suggest that the amount of Lewis acidity sites on catalyst surface increases significantly after the introduction of Zr, thereby enhancing the activity of catalyst for CF4 decomposition. The results of XPS analyses confirms the electrons transfer from Zr to Al, which contribute to the increase in Lewis acidity sites. The results of this work will help the development of more effective catalysts for CF4 decomposition. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
Supramolecular Immobilization of Adamantyl and Carboxylate Modified N-Heterocyclic Carbene Ligand on Cucurbituril Substrates
Molecules 2022, 27(5), 1662; https://doi.org/10.3390/molecules27051662 - 03 Mar 2022
Abstract
Herein, the design, synthesis, supramolecular interactions and structural analysis of a novel bidentate carboxylate chelating N-heterocylic carbene (NHC) ligand is presented. The NHC structure was modified to strategically incorporate adamantyl moiety for the formation of a supramolecular complex with host molecules such as [...] Read more.
Herein, the design, synthesis, supramolecular interactions and structural analysis of a novel bidentate carboxylate chelating N-heterocylic carbene (NHC) ligand is presented. The NHC structure was modified to strategically incorporate adamantyl moiety for the formation of a supramolecular complex with host molecules such as cucurbiturils. The adamantyl modified NHC ligand could potentially be used in recoverable homogeneous catalysts when Immobilized on a solid support via host–guest chemistry. As a versatile precursor, NHC ligand (8) was synthesized and characterized by 1H-NMR, 13C-NMR, FTIR, single crystal x-ray crystallography and elemental analysis. A proof-of-principle non-covalent immobilization of the NHC ligand (8) with a Cucurbit[7]uril (CB7) host was demonstrated using 1H-NMR titration. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Graphical abstract

Article
Chloroaluminate Ionic Liquid Immobilized on Magnetic Nanoparticles as a Heterogeneous Lewis Acidic Catalyst for the Friedel–Crafts Sulfonylation of Aromatic Compounds
Molecules 2022, 27(5), 1644; https://doi.org/10.3390/molecules27051644 - 02 Mar 2022
Cited by 2
Abstract
Chloroaluminate ionic liquid bound on magnetic nanoparticles (Fe3O4@O2Si[PrMIM]Cl·AlCl3) was prepared and used as a heterogenous Lewis acidic catalyst for the Friedel–Crafts sulfonylation of aromatic compounds with sulfonyl chlorides or p-toluenesulfonic anhydride. The catalyst’s stability, [...] Read more.
Chloroaluminate ionic liquid bound on magnetic nanoparticles (Fe3O4@O2Si[PrMIM]Cl·AlCl3) was prepared and used as a heterogenous Lewis acidic catalyst for the Friedel–Crafts sulfonylation of aromatic compounds with sulfonyl chlorides or p-toluenesulfonic anhydride. The catalyst’s stability, efficiency, easy recovery, and high recyclability without considerable loss of catalytic capability after four recycles were evidence of its advantages. Furthermore, the stoichiometry, wide substrate scope, short reaction time, high yield of sulfones, and solvent-free reaction condition also made this procedure practical, ecofriendly, and economical. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Article
Preparation of Highly Active Cu/SiO2 Catalysts for Furfural to 2-Methylfuran by Ammonia Evaporation Method
Catalysts 2022, 12(3), 276; https://doi.org/10.3390/catal12030276 - 01 Mar 2022
Cited by 1
Abstract
Biomass plays an important role in the green manufacture of high value-added chemicals. Among them, the conversion of furfural (FFA) into 2-methylfuran (2-MF), catalyzed by a copper-chromium catalyst, is important in its industrial application. However, the use of chromium is limited due to [...] Read more.
Biomass plays an important role in the green manufacture of high value-added chemicals. Among them, the conversion of furfural (FFA) into 2-methylfuran (2-MF), catalyzed by a copper-chromium catalyst, is important in its industrial application. However, the use of chromium is limited due to its toxicity and pollution of the environment. In this paper, a Cu/SiO2 catalyst, prepared by the ammonia evaporation method, shows a better catalytic performance compared with that prepared by the co-precipitation method for the vapor-phase hydrodeoxygenation of FFA. The selectivity of 2-MF is higher than 80% with almost a complete conversion of FFA. Combined with the characterizations, the superiority of the ammonia evaporation method is attributed to the reduction of highly dispersed copper species and the increased Cu+/(Cu+ + Cu0) ratio due to the formation of a large content of copper phyllosilicate during the preparation. Moreover, Cu+ sites can act as a weak acid site, which improve the surface acidity of the catalyst and facilitate the formation of 2-MF. This new catalytic system provides a feasible and promising strategy for the industrial preparation of 2-MF from FFA, and effectively utilizes biomass resources to promote the development of biomass industry. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Graphical abstract

Article
Photo-Fenton Degradation of Methyl Orange with Dunino Halloysite as a Source of Iron
Catalysts 2022, 12(3), 257; https://doi.org/10.3390/catal12030257 - 26 Feb 2022
Cited by 2
Abstract
The Fenton reaction is one of the most important processes for water and soil remediation, although this process has some drawbacks such as the use of H2O2 in large amounts, the formation of sludge due to the use of iron [...] Read more.
The Fenton reaction is one of the most important processes for water and soil remediation, although this process has some drawbacks such as the use of H2O2 in large amounts, the formation of sludge due to the use of iron salts, and the need for acid pH values. Here we present the use of a natural clay, modified by acid treatment, as a heterogeneous catalyst to replace soluble iron salts and to avoid the use of water peroxide, resulting in a considerable increase in the attractiveness of the process. Halloysite (HT) clay from the Dunino mine consists of alumina and silica layers with the presence of iron species acting as a source of Fe ions. The etching of alumina layers using hydrochloric acid induces the release of iron species (mainly ions) in the solution, giving rise to the photodegradation activity of organic contaminants in water (i.e., Methyl Orange, MO) under UV irradiation without the need for hydrogen peroxide and avoiding the formation of sludges. MO adsorption properties and MO photodegradation ability were investigated for untreated and acid treated samples, respectively, to achieve the optimal process conditions. MO was not adsorbed on the clay’s surface due to electrostatic repulsion, but a complete degradation was observed after three hours under UV irradiation. The kinetics of photodegradation and the values of the half-life time are presented as a measure of the degradation rate. The proposed process shows a new route for effective remediation of water containing biologically active organic substances dissolved in it. Full article
(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)
Show Figures

Figure 1

Back to TopTop