Artykuły w czasopismach: „Novel Catalysis”

1

Wang, Dabin, Weisong Yu, Bin Jiang, Tao Zeng, Dean Song, Song Fang, Yizhi Zhang i Jiguang Zhang. "A Novel Chemiluminescent Method for Efficient Evaluation of Heterogeneous Fenton Catalysts Using Cigarette Tar". Toxics 11, nr 1 (29.12.2022): 30. http://dx.doi.org/10.3390/toxics11010030.

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The evaluation of the catalytic capacity of catalysts is indispensable research, as catalytic capacity is a crucial factor to dictate the efficiency of heterogeneous Fenton catalysis. Herein, we obtained cigarette tar-methanol extracts (CTME) by applying methanol to cigarette tar and found that CTME could cause CL reactions with Fe2+/H2O2 systems in acidic, neutral, and alkaline media. The CL spectrum experiment indicated that the emission wavelengths of the CTME CL reaction with Fe2+/H2O2 systems were about 490 nm, 535 nm, and 590 nm. Quenching experiments confirmed that hydroxyl radicals (•OH) were responsible for the CL reaction for CTME. Then the CL property of CTME was applied in-situ to rapidly determine the amounts of •OH in tetrachloro-1,4-benzoquinone (TCBQ)/H2O2 system in acidic, neutral and alkaline media, and the CL intensities correlated the best (R2 = 0.99) with TCBQ concentrations. To demonstrate the utility of the CTME CL method, the catalytic capacity of different types and concentrations of catalysts in heterogeneous Fenton catalysis were examined. It was found that the order of CL intensities was consistent with the order of degradation efficiencies of Rhodamine B, indicating that this method could distinguish the catalytic capacity of catalysts. The CTME CL method could provide a convenient tool for the efficient evaluation of the catalytic capacity of catalysts in heterogeneous Fenton catalysis.

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Wan, Qiang, Sen Lin i Hua Guo. "Frustrated Lewis Pairs in Heterogeneous Catalysis: Theoretical Insights". Molecules 27, nr 12 (10.06.2022): 3734. http://dx.doi.org/10.3390/molecules27123734.

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Frustrated Lewis pair (FLP) catalysts have attracted much recent interest because of their exceptional ability to activate small molecules in homogeneous catalysis. In the past ten years, this unique catalysis concept has been extended to heterogeneous catalysis, with much success. Herein, we review the recent theoretical advances in understanding FLP-based heterogeneous catalysis in several applications, including metal oxides, functionalized surfaces, and two-dimensional materials. A better understanding of the details of the catalytic mechanism can help in the experimental design of novel heterogeneous FLP catalysts.

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Ranocchiari, Marco, Christian Lothschütz, Daniel Grolimund i Jeroen Anton van Bokhoven. "Single-atom active sites on metal-organic frameworks". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 468, nr 2143 (14.03.2012): 1985–99. http://dx.doi.org/10.1098/rspa.2012.0078.

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Single-site heterogeneous catalysis has been recently accepted as a novel branch of heterogeneous catalysis. Catalysts with single-atom active sites (SAHCs) allow the design and fine-tuning of the active moiety, and can potentially combine the advantages of heterogeneous and homogeneous catalysis. This study illustrates how porous metal-organic frameworks (MOFs) can be synthesized with homogeneous distribution of SAHCs. The catalytic potential of MIXMOFs is shown. A short overview of catalysis with mesoporous silica materials is described to demonstrate their importance in SAHC.

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Zhang, Meng. "A Novel Energy Band Match Method and a Highly Efficient CuO–Co3O4@SiO2 Catalyst for Dimethyl Carbonate Synthesis from CO2". Science of Advanced Materials 13, nr 1 (1.01.2021): 115–22. http://dx.doi.org/10.1166/sam.2021.3848.

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The present research on dimethyl carbonate (DMC) synthesis from CO2 was short of effective theoretical guidance and catalyst design was also blind. A kind of regular relationship was found from catalyst structure calculation and activity experiments. Therefore, a novel energy band matching method was proposed. After substantial verification experiments, it was proved to be correct. Whether one certain catalyst has catalytic activity can be judged predictably according to this novel method. Novel and efficient catalysts can be designed or selected on the basis of designer's wishes. Based on this method, three efficient catalysts were prepared and CuO–Co3O4@SiO2 catalyst had the best catalytic performance. In a word, once it is applied in catalysts research, there will be a huge progress in catalysis and materials science fields.

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Fino, Debora, Nunzio Russo, Emanuele Cauda, Davide Mescia, Simone Solaro, Guido Saracco i Vito Specchia. "Novel Approches in Oxidative Catalysis for Diesel Particulate Abatement". Advances in Science and Technology 45 (październik 2006): 2083–88. http://dx.doi.org/10.4028/www.scientific.net/ast.45.2083.

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Next 2008 European legislation on diesel engines will impose the use of specific traps, placed in the car exhaust line, so as to meet very stringent particulate emission limits (0.005 g/km). This paper provides a survey of the advancement status of R&D in the field of diesel particulate traps. Special emphasis is given to the combined use of traps and catalysts for regeneration purposes via catalytic combustion of the collected soot in the traps. Issues like trap materials selection, catalyst development, catalytic vs. non-catalytic trap performance are addressed. Specific highlights of the research in catalytic materials developed at Politecnico di Torino in the framework of EU projects will also be provided. In order to enhance the soot-catalyst contact conditions, several kinds of catalysts have been developed: oxygen spillover oxide, mobile catalysts based on alkali vanadates, spinels for the combined removal of particulate and NOx, precious metals enabling the NO oxidation to NO2 followed by reaction of this latter with particulate, heavy metal oxides, alkalimetal substituted perovskites capable of delivering oxygen species. An overview of these different approaches to soot oxidation will be provided pointing the way towards possible synergetic effects in multi-component catalysts.

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Moene, R., M. Makkee i J. A. Moulijn. "Novel application of catalysis in the synthesis of catalysts". Catalysis Letters 34, nr 3-4 (1995): 285–91. http://dx.doi.org/10.1007/bf00806877.

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Gai, P. L., K. Kourtakis, H. Dindi i S. Ziemecki. "Novel Xerogel Catalyst Materials for Hydrogenation Reactions and the Role of Atomic Scale Interfaces". Microscopy and Microanalysis 5, S2 (sierpień 1999): 704–5. http://dx.doi.org/10.1017/s1431927600016846.

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We are developing a new family of heterogeneous catalysts for hydrogenation catalysis. Catalyst synthesis is accomplished using colloidal polymerization chemistry which produce high surface area xerogel catalysts. These xerogels have been synthesized by one-step sol gel chemistry. These catalysts contain ruthenium and modifiers such as gold occluded or incorporated in a titanium oxide matrix. The materials, especially the modified systems exhibit favorable performance in microreactor evaluations for hydrogenation reactions and exhibit high activities. Nanostructural studies have revealed that the materials contain dispersed catalyst clusters which are desirable microstructures for the catalysis since the majority of the atoms are exposed to catalysis and are potentially active sites.The composition and atomic structure of the xerogel catalysts containing ruthenium and other metals have been examined using our in-house developments of environmental high resolution electron microscopy (EHREM) the atomic scale [1-3] and low voltage high resolution SEM (LVSEM)[4] methods.

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Yan, Ning. "Novel materials for catalysis". Catalysis Today 278 (grudzień 2016): 185–86. http://dx.doi.org/10.1016/j.cattod.2016.10.006.

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Armor, John N. "Novel catalysis for FCC". Applied Catalysis A: General 111, nr 2 (kwiecień 1994): N20—N21. http://dx.doi.org/10.1016/0926-860x(94)85055-0.

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Zhu, Junjie, Takehiko Gotoh, Satoshi Nakai i Masahiro Sadakane. "Synthesis and Characterization of a Novel Heteropoly Acid/Hydrogel Composite". MATEC Web of Conferences 333 (2021): 11005. http://dx.doi.org/10.1051/matecconf/202133311005.

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Catalysis by Heteropoly acids (HPAs) and polyoxometalates (POMs) having a higher demand worldwide, as it can be designed to accelerate complex reactions and be more environmentally friendly. However, recycling of water-soluble solid catalysts remains a problem. The synthesis of a recyclable composite with catalytic properties is the key to better use of HPAs and POMs. Many researches have mentioned the method of synthesis by immersing a porous carrier in a supported solution. However, the catalytic stabilities of the previously studied composites after multiple uses have rarely been mentioned. In this research, a novel idea is proposed to synthesize a heteropoly acid supported composite. A complex hydrogel with catalytic properties was synthesized by mixing an anionic monomer with a heteropoly acid. The heteropoly acid particles were inserted inside the hydrogel by the interaction forces between the anions. Thus, preventing the water-soluble heteropoly acid from being lost during the catalytic reaction. The complex hydrogel is consisted of the anionic monomer 2-acrylamide-2methylpropanesulfonic acid (AMPS) as a carrier, N,N’-Methylenebisacrylamide (MBAA) as crosslinkers and the typical Keggin-type HPA: H3PW12O40. At last, a composite with (NH4)3PW12O40 particles was synthesized.

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Zhu, Junjie, Takehiko Gotoh, Satoshi Nakai i Masahiro Sadakane. "Synthesis and Characterization of a Novel Heteropoly Acid/Hydrogel Composite". MATEC Web of Conferences 333 (2021): 11005. http://dx.doi.org/10.1051/matecconf/202133311005.

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Catalysis by Heteropoly acids (HPAs) and polyoxometalates (POMs) having a higher demand worldwide, as it can be designed to accelerate complex reactions and be more environmentally friendly. However, recycling of water-soluble solid catalysts remains a problem. The synthesis of a recyclable composite with catalytic properties is the key to better use of HPAs and POMs. Many researches have mentioned the method of synthesis by immersing a porous carrier in a supported solution. However, the catalytic stabilities of the previously studied composites after multiple uses have rarely been mentioned. In this research, a novel idea is proposed to synthesize a heteropoly acid supported composite. A complex hydrogel with catalytic properties was synthesized by mixing an anionic monomer with a heteropoly acid. The heteropoly acid particles were inserted inside the hydrogel by the interaction forces between the anions. Thus, preventing the water-soluble heteropoly acid from being lost during the catalytic reaction. The complex hydrogel is consisted of the anionic monomer 2-acrylamide-2methylpropanesulfonic acid (AMPS) as a carrier, N,N’-Methylenebisacrylamide (MBAA) as crosslinkers and the typical Keggin-type HPA: H3PW12O40. At last, a composite with (NH4)3PW12O40 particles was synthesized.

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Trigoura, Leslie, Yalan Xing i Bhanu P. S. Chauhan. "Recyclable Catalysts for Alkyne Functionalization". Molecules 26, nr 12 (9.06.2021): 3525. http://dx.doi.org/10.3390/molecules26123525.

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In this review, we present an assessment of recent advances in alkyne functionalization reactions, classified according to different classes of recyclable catalysts. In this work, we have incorporated and reviewed the activity and selectivity of recyclable catalytic systems such as polysiloxane-encapsulated novel metal nanoparticle-based catalysts, silica–copper-supported nanocatalysts, graphitic carbon-supported nanocatalysts, metal organic framework (MOF) catalysts, porous organic framework (POP) catalysts, bio-material-supported catalysts, and metal/solvent free recyclable catalysts. In addition, several alkyne functionalization reactions have been elucidated to demonstrate the success and efficiency of recyclable catalysts. In addition, this review also provides the fundamental knowledge required for utilization of green catalysts, which can combine the advantageous features of both homogeneous (catalyst modulation) and heterogeneous (catalyst recycling) catalysis.

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Miele, Margherita, Veronica Pillari, Vittorio Pace, Andrés R. Alcántara i Gonzalo de Gonzalo. "Application of Biobased Solvents in Asymmetric Catalysis". Molecules 27, nr 19 (8.10.2022): 6701. http://dx.doi.org/10.3390/molecules27196701.

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The necessity of more sustainable conditions that follow the twelve principles of Green Chemistry have pushed researchers to the development of novel reagents, catalysts and solvents for greener asymmetric methodologies. Solvents are in general a fundamental part for developing organic processes, as well as for the separation and purification of the reaction products. By this reason, in the last years, the application of the so-called green solvents has emerged as a useful alternative to the classical organic solvents. These solvents must present some properties, such as a low vapor pressure and toxicity, high boiling point and biodegradability, and must be obtained from renewable sources. In the present revision, the recent application of these biobased solvents in the synthesis of optically active compounds employing different catalytic methodologies, including biocatalysis, organocatalysis and metal catalysis, will be analyzed to provide a novel tool for carrying out more ecofriendly organic processes.

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Baird, Michael C. "Catalysis by organotransition metal compounds: Synergism between the pure and the applied1". Canadian Journal of Chemistry 81, nr 4 (1.04.2003): 330–37. http://dx.doi.org/10.1139/v03-065.

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The modern era of transition-metal-catalyzed polymerization of alkenes began with the Nobel Prize winning work of Ziegler and Natta in the 1950s, but the field has exploded since the mid-1980s and anticipated applications of organometallic catalysts are being spectacularly realized. Our research in metal-catalyzed alkene polymerization began about ten years ago with an investigation of the catalytic applications of half-sandwich complexes of the Group 4 metals, and this lecture will describe our efforts to find both better initiators to make known commercial polymers and new initiators to make novel polymeric materials. Good luck, bad luck, blind alleys, and serendipity have all played key roles in our research, resulting ultimately in a very satisfying convergence of the motives for pure, and the needs of applied, research.Key words: alkene, polymerization, Ziegler, catalysis, carbocationic, titanium.

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Kidwai, Mazaahir, Priya, Shweta Rastogi i Kavita Singhal. "A new microwave-assisted synthetic approach to novel pyrimido[4,5-d]pyrimidines". Canadian Journal of Chemistry 85, nr 7-8 (1.07.2007): 491–95. http://dx.doi.org/10.1139/v07-065.

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An environmentally benign approach for the synthesis of novel 7-substituted 5-aryl-1H-pyrimido[4,5-d]pyrimidine-2,4-diones, using mineral supports for their catalytic role and as energy transfer media, is described. The methodology eliminates the usage of solvent during the reaction. The rate enhancement and high yield is attributed to the coupling of solvent-free conditions with microwaves. Further, the role of various supports is studied during the reaction and it is concluded that a MW-assisted basic alumina catalysed reaction is the best in terms of catalysis as well as reaction time and yield.Key words: microwave (MW) irradiation, SBT, pyrimido[4,5-d]pyrimidines, alumina, environmentally benign.

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Adams, Nicholas J., Joachim Bargon, John M. Brown, Edward J. Farrington, Erwan Galardon, Ralf Giernoth, Hanjo Heinrich, Benjamin D. John i Kenji Maeda. "Interplay of synthesis and mechanism in asymmetric homogeneous catalysis". Pure and Applied Chemistry 73, nr 2 (1.01.2001): 343–46. http://dx.doi.org/10.1351/pac200173020343.

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Asymmetric homogeneous catalysis forms one of the main planks of modern organic synthesis. It has developed rapidly and largely through the application of novel ligands, whose design is very much based on insight and intuition. At the same time, a better understanding of catalytic reaction mechanisms can contribute to further progress, since it can identify the intimate relationship between ligand structure and successful applications. The presentation will concentrate on the author's research with complexes of the late transition metals and include the search for superior methodologies in hydroboration, as well as ventures into the chemistry of reactive intermediates. The latter will be exemplified from work with rhodium and palladium catalysts.

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Subramanian, Palaniappan, Dalila Meziane, Robert Wojcieszak, Franck Dumeignil, Rabah Boukherroub i Sabine Szunerits. "Plasmon-Induced Electrocatalysis with Multi-Component Nanostructures". Materials 12, nr 1 (24.12.2018): 43. http://dx.doi.org/10.3390/ma12010043.

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Noble metal nanostructures are exceptional light absorbing systems, in which electron–hole pairs can be formed and used as “hot” charge carriers for catalytic applications. The main goal of the emerging field of plasmon-induced catalysis is to design a novel way of finely tuning the activity and selectivity of heterogeneous catalysts. The designed strategies for the preparation of plasmonic nanomaterials for catalytic systems are highly crucial to achieve improvement in the performance of targeted catalytic reactions and processes. While there is a growing number of composite materials for photochemical processes-mediated by hot charge carriers, the reports on plasmon-enhanced electrochemical catalysis and their investigated reactions are still scarce. This review provides a brief overview of the current understanding of the charge flow within plasmon-enhanced electrochemically active nanostructures and their synthetic methods. It is intended to shed light on the recent progress achieved in the synthesis of multi-component nanostructures, in particular for the plasmon-mediated electrocatalysis of major fuel-forming and fuel cell reactions.

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Hamzaoui, Bilel, Anissa Bendjeriou-Sedjerari, Eva Pump, Edy Abou-Hamad, Rachid Sougrat, Andrei Gurinov, Kuo-Wei Huang i in. "Atomic-level organization of vicinal acid–base pairs through the chemisorption of aniline and derivatives onto mesoporous SBA15". Chemical Science 7, nr 9 (2016): 6099–105. http://dx.doi.org/10.1039/c6sc01229a.

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Bridges, Denzel, David Fieser, Jannira J. Santiago i Anming Hu. "Novel Frontiers in High-Entropy Alloys". Metals 13, nr 7 (27.06.2023): 1193. http://dx.doi.org/10.3390/met13071193.

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There is little doubt that there is significant potential for high-entropy alloys (HEAs) in cryogenic and aerospace applications. However, given the immense design space for HEAs, there is much more to be explored. This review will focus on four areas of application for HEAs that receive less attention. These focus areas include joining technologies, HEA nanomaterial synthesis, catalysis, and marine applications. The performance of HEAs as a filler metal for welding and brazing as well as their performance as a welded/brazed base metal will be discussed. Various methods for synthesizing HEA nanomaterials are reviewed with specifically highlighted applications in catalysis and energy storage. HEA catalysts, in particular, will be discussed in detail regarding their effectiveness, selectiveness, and stability. Marine applications are explored given the inherent corrosion resistance of HEAs as well as superior antifouling properties that make HEAs an intriguing marine-ready material.

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Lazzarini, Andrea, Roberta Colaiezzi, Francesco Gabriele i Marcello Crucianelli. "Support–Activity Relationship in Heterogeneous Catalysis for Biomass Valorization and Fine-Chemicals Production". Materials 14, nr 22 (11.11.2021): 6796. http://dx.doi.org/10.3390/ma14226796.

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Heterogeneous catalysts are progressively expanding their field of application, from high-throughput reactions for traditional industrial chemistry with production volumes reaching millions of tons per year, a sector in which they are key players, to more niche applications for the production of fine chemicals. These novel applications require a progressive utilization reduction of fossil feedstocks, in favor of renewable ones. Biomasses are the most accessible source of organic precursors, having as advantage their low cost and even distribution across the globe. Unfortunately, they are intrinsically inhomogeneous in nature and their efficient exploitation requires novel catalysts. In this process, an accurate design of the active phase performing the reaction is important; nevertheless, we are often neglecting the importance of the support in guaranteeing stable performances and improving catalytic activity. This review has the goal of gathering and highlighting the cases in which the supports (either derived or not from biomass wastes) share the worth of performing the catalysis with the active phase, for those reactions involving the synthesis of fine chemicals starting from biomasses as feedstocks.

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Nguyen, Xuan B., Yuji Nakano i David W. Lupton. "Polarity Inversion Catalysis by the 1,4-Addition of N-Heterocyclic Carbenes". Australian Journal of Chemistry 73, nr 1 (2020): 1. http://dx.doi.org/10.1071/ch19550.

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Polarity inversion is the hallmark of N-heterocyclic carbene (NHC) organocatalysis, with the generation and reaction of acyl anion equivalents known for more than 70 years. In contrast, polarity inversion through 1,4-addition of NHCs to conjugate acceptors was first applied in a catalytic reaction in 2006. This sub-field of NHC-organocatalysis has developed steadily over the subsequent years, enabling novel coupling reactions, enantioselective cycloisomerizations, polymerizations, and other reactions. In this review, this emerging area of NHC-organocatalysis is discussed with comprehensive coverage. In addition, notes regarding the use of other Lewis base catalysts for related reactions, and comments regarding NHC selection for this type of catalysis, are provided.

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Kojima, Takayuki, Satoshi Kameoka, Shinpei Fujii, Shigenori Ueda i An-Pang Tsai. "Catalysis-tunable Heusler alloys in selective hydrogenation of alkynes: A new potential for old materials". Science Advances 4, nr 10 (październik 2018): eaat6063. http://dx.doi.org/10.1126/sciadv.aat6063.

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Heusler alloys (X2YZ) are well-established intermetallic compound materials in various fields because their function can be precisely adjusted by elemental substitution (e.g., X2YZ1−xZ′x). Although intermetallic compound catalysts started attracting attention recently, catalysis researchers are not familiar with Heusler alloys. We report their potential as novel catalysts focusing on the selective hydrogenation of alkynes. We found that Co2MnGe and Co2FeGe alloys have great alkene selectivity. Mutual substitution of Mn and Fe (Co2MnxFe1−xGe) enhanced the reaction rate without changing selectivity. The substitution of Ga for Ge decreased the selectivity but increased the reaction rate monotonically with Ga composition. Elucidation of these mechanisms revealed that the fine tuning of catalytic properties is possible in Heusler alloys by separately using ligand and ensemble effects of elemental substitution.

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Isaeva, Vera I., Oleg M. Nefedov i Leonid M. Kustov. "Metal–Organic Frameworks-Based Catalysts for Biomass Processing". Catalysts 8, nr 9 (31.08.2018): 368. http://dx.doi.org/10.3390/catal8090368.

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: Currently, metal–organic frame works (MOFs) as novel hybrid nanoporous materials are a top research interest, including endeavors in heterogeneous catalysis. MOF materials are promising heterogeneous catalytic systems due to their unique characteristics, such as a highly ordered structure, a record high surface area and a compositional diversity, which can be precisely tailored. Very recently, these metal-organic matrices have been proven as promising catalysts for biomass conversion into value-added products. The relevant publications show that the structure of MOFs can contribute essentially to the advanced catalytic performance in processes of biomass refining. This review aims at the consideration of the different ways for the rational design of MOF catalysts for biomass processing. The particular characteristics and peculiarities of the behavior of different MOF based catalytic systems including hybrid nanomaterials and composites will be also discussed by illustrating their outstanding performance with appropriate examples relevant to biomass catalytic processing.

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Sheldon, Roger A. "Atom efficiency and catalysis in organic synthesis". Pure and Applied Chemistry 72, nr 7 (1.01.2000): 1233–46. http://dx.doi.org/10.1351/pac200072071233.

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The key to waste minimization in fine chemicals manufacture is the widespread substitution of classical organic syntheses employing stoichiometric amounts of inorganic reagents with cleaner, catalytic alternatives. The E factors (by waste per kg product) of chemical processes increase dramatically on going downstream from bulk to fine chemicals and pharmaceuticals, mainly owing to the use of "stoichiometric" methods. The concept of atom efficiency is a useful tool for rapid evaluation of the amount of waste generated by alternative processes. The general theme of atom-efficient, catalytic processes is illustrated with industrially relevant examples. These include catalysis by solid acids and bases, catalytic reductions and oxidations, catalytic C_C bond formation, asymmetric catalysis, biocatalysis, and catalysis in novel media (aqueous and fluorous biphasic systems, supercritical fluids, and ionic liquids).

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Zheng, Yifan, Lin Gu, Yining Li, Jamal Ftouni i Abhishek Dutta Chowdhury. "Revisiting the Semi-Hydrogenation of Phenylacetylene to Styrene over Palladium-Lead Alloyed Catalysts on Precipitated Calcium Carbonate Supports". Catalysts 13, nr 1 (27.12.2022): 50. http://dx.doi.org/10.3390/catal13010050.

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The quest for improved heterogeneous catalysts often leads to sophisticated solutions, which are expensive and tricky to scale up industrially. Herein, the effort to upgrade the existing inorganic nonmetallic materials has seldom been prioritized by the catalysis community, which could deliver cost-effective solutions to upgrade the industrial catalysts catalog. With this philosophy in mind, we demonstrate in this work that alloyed palladium-lead (Pd-Pb) deposited on novel precipitated calcium carbonate (PCC) supports could be considered an upgraded version of the industrial Lindlar catalyst for the semi-hydrogenation of phenylacetylene to styrene. By utilizing PCC supports of variable surface areas (up to 60 m2/g) and alloyed Pd-Pb loading, supported by material characterization tools, we showcase that achieving the “active-site isolation” feature could be the most pivotal criterion to maximize semi-hydrogenated alkenes selectivity at the expense of prohibiting the complete hydrogenation to alkanes. The calcite phase of our PCC supports governs the ultimate catalysis, via complexation with uniformly distributed alloyed Pb, which may facilitate the desired “active-site isolation” feature to boost the selectivity to the preferential product. Through this work, we also advocate increasing research efforts on mineral-based inorganic nonmetallic materials to deliver novel and improved cost-effective catalytic systems.

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Msezane, Alfred Z., Zineb Felfli i Dmitri Sokolovski. "Novel mechanism for nanoscale catalysis". Journal of Physics B: Atomic, Molecular and Optical Physics 43, nr 20 (27.09.2010): 201001. http://dx.doi.org/10.1088/0953-4075/43/20/201001.

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Evans, J. "Novel materials in heterogeneous catalysis". Journal of Electroanalytical Chemistry and Interfacial Electrochemistry 305, nr 2 (maj 1991): 329–30. http://dx.doi.org/10.1016/0022-0728(91)85529-x.

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Xu, Jun Qiang, Fang Guo, Jun Li, Xiu Zhi Ran i Yan Tang. "Synthesis of the Cu/Flokite Catalysts and their Performances for Catalytic Wet Peroxide Oxidation of Phenol". Advanced Materials Research 560-561 (sierpień 2012): 869–72. http://dx.doi.org/10.4028/www.scientific.net/amr.560-561.869.

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The supported Cu/Flokite catalysts were prepared by conventional incipient wetness impregnation. The catalysis oxidation degradation of phenol was carried out in heterogeneous catalyst and H2O2 process. The results indicated that the reaction system with catalyst and hydrogen peroxide was more benefit to degradation of phenol. When the phenol initial concentration was 100 mg/L, the phenol removal over the 2.5%Cu -2.5% Fe/Flokite catalyst could reach 96%. The peroxide catalytic oxidation process over the enhanced heterogeneous catalyst would be a novel technique for the treatment of phenol wastewater.

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Li, Yong Xiu, Chang Yong Sun, Chang Jiang Yu, Chao Xian Wang, Yun Jun Liu i Ying Bing Song. "Graphene Oxide and its Applications in Catalysis". Advanced Materials Research 476-478 (luty 2012): 1488–95. http://dx.doi.org/10.4028/www.scientific.net/amr.476-478.1488.

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Graphene, a two-dimensional carbon material, has attracted tremendous research interest in recent years due to its exceptional properties, such as excellent electrical, mechanical and thermal properties. Meanwhile, various kinds of novel functional materials based on Graphene oxide are employed in different fields like solar cell, sensor and catalysis. With the increasing number of catalysts during synthesizing graphene-based composites, the development of catalysis science and technology will surely be promoted. This paper reviews recent advances in the preparation and structure of graphene oxide, especially its applications in catalysis fields.

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Konsolakis, Michalis, i Maria Lykaki. "Facet-Dependent Reactivity of Ceria Nanoparticles Exemplified by CeO2-Based Transition Metal Catalysts: A Critical Review". Catalysts 11, nr 4 (31.03.2021): 452. http://dx.doi.org/10.3390/catal11040452.

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The rational design and fabrication of highly-active and cost-efficient catalytic materials constitutes the main research pillar in catalysis field. In this context, the fine-tuning of size and shape at the nanometer scale can exert an intense impact not only on the inherent reactivity of catalyst’s counterparts but also on their interfacial interactions; it can also opening up new horizons for the development of highly active and robust materials. The present critical review, focusing mainly on our recent advances on the topic, aims to highlight the pivotal role of shape engineering in catalysis, exemplified by noble metal-free, CeO2-based transition metal catalysts (TMs/CeO2). The underlying mechanism of facet-dependent reactivity is initially discussed. The main implications of ceria nanoparticles’ shape engineering (rods, cubes, and polyhedra) in catalysis are next discussed, on the ground of some of the most pertinent heterogeneous reactions, such as CO2 hydrogenation, CO oxidation, and N2O decomposition. It is clearly revealed that shape functionalization can remarkably affect the intrinsic features and in turn the reactivity of ceria nanoparticles. More importantly, by combining ceria nanoparticles (CeO2 NPs) of specific architecture with various transition metals (e.g., Cu, Fe, Co, and Ni) remarkably active multifunctional composites can be obtained due mainly to the synergistic metalceria interactions. From the practical point of view, novel catalyst formulations with similar or even superior reactivity to that of noble metals can be obtained by co-adjusting the shape and composition of mixed oxides, such as Cu/ceria nanorods for CO oxidation and Ni/ceria nanorods for CO2 hydrogenation. The conclusions derived could provide the design principles of earth-abundant metal oxide catalysts for various real-life environmental and energy applications.

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Nishchakova, Alina D., Lyubov G. Bulusheva i Dmitri A. Bulushev. "Supported Ni Single-Atom Catalysts: Synthesis, Structure, and Applications in Thermocatalytic Reactions". Catalysts 13, nr 5 (6.05.2023): 845. http://dx.doi.org/10.3390/catal13050845.

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Nickel is a well-known catalyst in hydrogenation and dehydrogenation reactions. It is currently used in industrial processes as a homogenous and heterogeneous catalyst. However, to reduce the cost and increase the efficiency of catalytic processes, the development of single-atom catalysts (SACs) seems promising. Some SACs have already shown increased activity and stability as compared to nanoparticle catalysts. From year to year, the number of reports devoted to nickel SACs is growing rapidly. Among them, there are very few articles devoted to thermal catalysis, but at the same time, this subject is important. Thus, this review discusses recent advances in the synthesis, structure, and application of nickel SACs, mainly in catalytic hydrogenation/dehydrogenation reactions and in the dry reforming of methane. The collected and analyzed data can be useful in the development of novel nickel SACs for various processes.

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Lindenthal, Lorenz, Raffael Rameshan, Harald Summerer, Thomas Ruh, Janko Popovic, Andreas Nenning, Stefan Löffler, Alexander Karl Opitz, Peter Blaha i Christoph Rameshan. "Modifying the Surface Structure of Perovskite-Based Catalysts by Nanoparticle Exsolution". Catalysts 10, nr 3 (1.03.2020): 268. http://dx.doi.org/10.3390/catal10030268.

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In heterogeneous catalysis, surfaces decorated with uniformly dispersed, catalytically-active (nano)particles are a key requirement for excellent performance. Beside standard catalyst preparation routines—with limitations in controlling catalyst surface structure (i.e., particle size distribution or dispersion)—we present here a novel time efficient route to precisely tailor catalyst surface morphology and composition of perovskites. Perovskite-type oxides of nominal composition ABO3 with transition metal cations on the B-site can exsolve the B-site transition metal upon controlled reduction. In this exsolution process, the transition metal emerges from the oxide lattice and migrates to the surface where it forms catalytically active nanoparticles. Doping the B-site with reducible and catalytically highly active elements, offers the opportunity of tailoring properties of exsolution catalysts. Here, we present the synthesis of two novel perovskite catalysts Nd0.6Ca0.4FeO3-δ and Nd0.6Ca0.4Fe0.9Co0.1O3-δ with characterisation by (in situ) XRD, SEM/TEM and XPS, supported by theory (DFT+U). Fe nanoparticle formation was observed for Nd0.6Ca0.4FeO3-δ. In comparison, B site cobalt doping leads, already at lower reduction temperatures, to formation of finely dispersed Co nanoparticles on the surface. These novel perovskite-type catalysts are highly promising for applications in chemical energy conversion. First measurements revealed that exsolved Co nanoparticles significantly improve the catalytic activity for CO2 activation via reverse water gas shift reaction.

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Wu, Jingyun. "Two-step synthesis and oxidizing power assessment of novel pyrylium". Theoretical and Natural Science 6, nr 1 (3.08.2023): 1–7. http://dx.doi.org/10.54254/2753-8818/6/20230107.

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Photoredox catalysis is a relatively new concept, and it involves the absorption of light for more productive use of lower energy radiation and to catalyze selective reactions. Traditionally, catalysts used for oxidation or reduction reactions were metal catalysts, such as iridium. However, these metal catalysts are not environmentally friendly and are expensive, prompting the use of organic catalysts. Pyrylium salt, an organic catalyst, can be used as a catalyst. However, the oxidizing ability of basic pyrylium is not that good and can still be improved. In this project, a pyrylium salt with substituents that include fluorine and chlorine (halogens) was synthesized to boost its oxidizing ability in an alcohol oxidation reaction due to its electron-withdrawing groups. Despite unsuccessful oxidation, there is still much research to prove that it can substitute for metal catalysts.

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Weinberg, Christina E., Zasha Weinberg i Christian Hammann. "Novel ribozymes: discovery, catalytic mechanisms, and the quest to understand biological function". Nucleic Acids Research 47, nr 18 (31.08.2019): 9480–94. http://dx.doi.org/10.1093/nar/gkz737.

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Abstract Small endonucleolytic ribozymes promote the self-cleavage of their own phosphodiester backbone at a specific linkage. The structures of and the reactions catalysed by members of individual families have been studied in great detail in the past decades. In recent years, bioinformatics studies have uncovered a considerable number of new examples of known catalytic RNA motifs. Importantly, entirely novel ribozyme classes were also discovered, for most of which both structural and biochemical information became rapidly available. However, for the majority of the new ribozymes, which are found in the genomes of a variety of species, a biological function remains elusive. Here, we concentrate on the different approaches to find catalytic RNA motifs in sequence databases. We summarize the emerging principles of RNA catalysis as observed for small endonucleolytic ribozymes. Finally, we address the biological functions of those ribozymes, where relevant information is available and common themes on their cellular activities are emerging. We conclude by speculating on the possibility that the identification and characterization of proteins that we hypothesize to be endogenously associated with catalytic RNA might help in answering the ever-present question of the biological function of the growing number of genomically encoded, small endonucleolytic ribozymes.

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Spino, Claude, Laurel Clouston i David Berg. "Novel, air-stable, lanthanide catalysts for the hetero Diels–Alder reaction". Canadian Journal of Chemistry 74, nr 9 (1.09.1996): 1762–64. http://dx.doi.org/10.1139/v96-195.

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Novel, air-stable, yttrium and ytterbium complexes were found effective in the catalysis of the typical hetero Diels–Alder reaction of crotonaldehyde and ethylvinyl ether. They represent an attractive solution to the problem of ligand lability in the realm of lanthanide catalysts. Key words: lanthanide, catalyst, hetero Diels–Alder, yttrium, ytterbium.

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Hajdu, Viktória, Emőke Sikora, Ferenc Kristály, Gábor Muránszky, Béla Fiser, Béla Viskolcz, Miklós Nagy i László Vanyorek. "Palladium Decorated, Amine Functionalized Ni-, Cd- and Co-Ferrite Nanospheres as Novel and Effective Catalysts for 2,4-Dinitrotoluene Hydrogenation". International Journal of Molecular Sciences 23, nr 21 (30.10.2022): 13197. http://dx.doi.org/10.3390/ijms232113197.

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2,4-diaminotoluene (TDA) is one of the most important polyurethane precursors produced in large quantities by the hydrogenation of 2,4-dinitrotoluene using catalysts. Any improvement during the catalysis reaction is therefore of significant importance. Separation of the catalysts by filtration is cumbersome and causes catalyst loss. To solve this problem, we have developed magnetizable, amine functionalized ferrite supported palladium catalysts. Cobalt ferrite (CoFe2O4-NH2), nickel ferrite (NiFe2O4-NH2), and cadmium ferrite (CdFe2O4-NH2) magnetic catalyst supports were produced by a simple coprecipitation/sonochemical method. The nanospheres formed contain only magnetic (spinel) phases and show catalytic activity even without noble metals (palladium, platinum, rhodium, etc.) during the hydrogenation of 2,4-dinitrotoluene, 63% (n/n) conversion is also possible. By decorating the supports with palladium, almost 100% TDA selectivity and yield were ensured by using Pd/CoFe2O4-NH2 and Pd/NiFe2O4-NH2 catalysts. These catalysts possess highly favorable properties for industrial applications, such as easy separation from the reaction medium without loss by means of a magnetic field, enhanced reusability, and good dispersibility in aqueous medium. Contrary to non-functionalized supports, no significant leaching of precious metals could be detected even after four cycles.

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Dipheko, Tshepo D., Vladimir V. Maximov, Mohamed E. Osman, Oleg L. Eliseev, Alexander G. Cherednichenko, Tatiana F. Sheshko i Victor M. Kogan. "Synthesis of Oxygenated Hydrocarbons from Ethanol over Sulfided KCoMo-Based Catalysts: Influence of Novel Fiber- and Powder-Activated Carbon Supports". Catalysts 12, nr 12 (23.11.2022): 1497. http://dx.doi.org/10.3390/catal12121497.

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Ethanol has become a viable feedstock for basic organic synthesis. The catalytic conversion of ethanol provides access to such chemicals as diethyl ether, ethyl acetate, and acetaldehyde. Carbonaceous materials are extensively studied as supports for heterogeneous catalysts due to their chemical and thermal stability, high surface area, and tunable texture. In this paper, ethanol conversion over K10Co3.7Mo12S-catalysts supported on novel activated carbon (AC) materials (i.e., novel powder-AC (DAS and YPK-1), fiber non-woven AC material (AHM), and fabric active sorption (TCA)) was investigated. The catalysts were prepared by the incipient wetness co-impregnation method followed by sulfidation. The catalysts were characterized by employing N2 adsorption–desorption measurements, TEM, SEM/EDX, UV–Vis spectroscopy, and XRF. Catalytic performance was assessed in a fixed-bed down-flow reactor operating at 320 °C, 2.5 MPa, and with continuous ethanol feeding in an He atmosphere. Activity is highly dependent on the support type and catalyst’s textural properties. The activity of the fiber-supported catalysts was found to be greater than the powder-supported catalysts. Ethanol conversion at T = 320 °C, P = 2.5 MPa, and GHSV = 760 L h−1 kgcat−1 increased as follows: (38.7%) KCoMoS2/YPK-1 < (49.5%) KCoMoS2/DAS < (58.2%) KCoMoS2/TCA < (67.1%) KCoMoS2/AHM. Catalysts supported by powder-AC enhanced the formation of MoS2-crystallites, whereas the high acidity of fiber-AC seemed to inhibit the formation of MoS2-crystallites. Simultaneously, a high surface area and a microporous catalytic structure enhance the formation of oxygenates from hydrocarbons. The dehydration and dehydrogenation reactions, which led to the creation of ethene and acetaldehyde, were shown to require a highly acidic catalyst, while the synthesis of ethyl acetate and higher alcohols required a less acidic catalyst.

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Zhong, Chenglin, Qingwen Zhou, Shengwen Li, Lin Cao, Jiachen Li, Zihan Shen, Haixia Ma, Jianguo Liu, Minghui Lu i Huigang Zhang. "Enhanced synergistic catalysis by a novel triple-phase interface design of NiO/Ru@Ni for the hydrogen evolution reaction". Journal of Materials Chemistry A 7, nr 5 (2019): 2344–50. http://dx.doi.org/10.1039/c8ta11171e.

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High-efficiency synergistic catalysis was realized by a novel triple-phase interface design of the bifunctional catalysts of NiO and Ru nanoparticles, leading to simultaneous enhancement of all elementary steps.

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Yu, Xuehua, Zhen Zhao, Yuechang Wei, Linlin Zhao i Jian Liu. "Three-dimensionally ordered macroporous K0.5MnCeOx/SiO2 catalysts: facile preparation and worthwhile catalytic performances for soot combustion". Catalysis Science & Technology 9, nr 6 (2019): 1372–86. http://dx.doi.org/10.1039/c8cy02580k.

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A series of novel catalysts with three-dimensionally ordered macroporous structures and active-component nanoparticles, exhibiting excellent catalytic performance for soot combustion, were fabricated.

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Gilea, Diana, Radu G. Ciocarlan, Elena M. Seftel, Pegie Cool i Gabriela Carja. "Engineering Heterostructures of Layered Double Hydroxides and Metal Nanoparticles for Plasmon-Enhanced Catalysis". Catalysts 12, nr 10 (11.10.2022): 1210. http://dx.doi.org/10.3390/catal12101210.

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Artificially designed heterostructures formed by close conjunctions of plasmonic metal nanoparticles (PNPs) and non-plasmonic (2D) lamellar nanostructures are receiving extensive interest. The synergistic interactions of the nanounits induce the manifestation of localized surface plasmon resonance (LSPR) in plasmonic metals in the specific environment of the 2D-light absorbing matrix, impacting their potential in plasmon enhanced catalysis. Specifically, layered double hydroxides (LDH) with the advantages of their unique 2D-layered structure, tuned optical absorption, ease of preparation, composition diversity, and high surface area, have emerged as very promising candidates for obtaining versatile and robust catalysts. In this review, we cover the available PNPs/LDH heterostructures, from the most used noble-metals plasmonic of Au and Ag to the novel non-noble-metals plasmonic of Cu and Ni, mainly focusing on their synthesis strategies toward establishing a synergistic response in the coupled nanounits and relevant applications in plasmonic catalysis. First, the structure–properties relationship in LDH, establishing the desirable features of the 2D-layered matrix facilitating photocatalysis, is shortly described. Then, we address the recent research interests toward fabrication strategies for PNPs/support heterostructures as plasmonic catalysts. Next, we highlight the synthesis strategies for available PNPs/LDH heterostructures, how these are entangled with characteristics that enable the manifestation of the plasmon-induced charge separation effect (PICS), co-catalytic effect, or nanoantenna effect in plasmonic catalysis with applications in energy related and environmental photocatalysis. Finally, some perspectives on the challenges and future directions of PNPs/LDHs heterostructures to improve their performance as plasmonic catalysts are discussed.

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Bulman Page, Philip C., Francesca S. Kinsey, Yohan Chan, Ian R. Strutt, Alexandra M. Z. Slawin i Garth A. Jones. "Novel binaphthyl and biphenyl α- and β-amino acids and esters: organocatalysis of asymmetric Diels–Alder reactions. A combined synthetic and computational study". Organic & Biomolecular Chemistry 16, nr 40 (2018): 7400–7416. http://dx.doi.org/10.1039/c8ob01795f.

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Asymmetric catalysis of the Diels–Alder reaction between cyclopentadiene and cinnamaldehydes has been studied using as catalysts a range of novel α- and β-aminoacids and aminoesters with binaphthyl and biphenyl backbones.

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Reetz, Manfred T., Martin Rentzsch, Andreas Pletsch, Matthias Maywald, Peter Maiwald, Jérôme J. P. Peyralans, Andrea Maichele i in. "Directed evolution of enantioselective hybrid catalysts: a novel concept in asymmetric catalysis". Tetrahedron 63, nr 28 (lipiec 2007): 6404–14. http://dx.doi.org/10.1016/j.tet.2007.03.177.

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Xu, Yan, Huiqing Zeng, Dan Zhao, Shuhua Wang, Shunmin Ding i Chao Chen. "Green and Efficient Acquirement of Unsaturated Ether from Direct and Selective Hydrogenation Coupling Unsaturated Aldehyde with Alcohol by Bi-Functional Al-Ni-P Heterogeneous Catalysts". Catalysts 13, nr 2 (18.02.2023): 439. http://dx.doi.org/10.3390/catal13020439.

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In view of the industrial importance of high-grade unsaturated ether (UE) and the inconvenience of acquiring the compound, herein, a series of low-cost Al-Ni-P catalysts in robust AlPO4/Ni2P structure possessing novel bi-functional catalytic features (hydrogenation activation and acid catalysis) were innovated, and testified to be efficient for directly synthesizing UE with a superior yield up to 97% from the selective hydrogenation coupling carbonyl of unsaturated aldehyde (cinnamaldehyde or citral) with C1–C5 primary or secondary alcohol under 0.1 MPa H2 and 393 K. The integrated advantages of high efficiency, green manner and convenient operation of the present heterogeneous catalytic system gave the system potential for feasibly harvesting high-grade unsaturated ether in related fine chemical synthesis networks.

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Li, Zhenzhong, Lorenz Rösler, Till Wissel, Hergen Breitzke, Kathrin Hofmann, Hans-Heinrich Limbach, Torsten Gutmann i Gerd Buntkowsky. "Design and characterization of novel dirhodium coordination polymers – the impact of ligand size on selectivity in asymmetric cyclopropanation". Catalysis Science & Technology 11, nr 10 (2021): 3481–92. http://dx.doi.org/10.1039/d1cy00109d.

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Novel dirhodium coordination polymers are synthesized and characterized by various spectroscopic techniques. The catalysts exhibit good stability and excellent catalytic performance and selectivity in the cyclopropanation of diazooxindoles.

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45

Kappis, Konstantinos, Christos Papadopoulos, Joan Papavasiliou, John Vakros, Yiannis Georgiou, Yiannis Deligiannakis i George Avgouropoulos. "Tuning the Catalytic Properties of Copper-Promoted Nanoceria via a Hydrothermal Method". Catalysts 9, nr 2 (1.02.2019): 138. http://dx.doi.org/10.3390/catal9020138.

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Copper-cerium mixed oxide catalysts have gained ground over the years in the field of heterogeneous catalysis and especially in CO oxidation reaction due to their remarkable performance. In this study, a series of highly active, atomically dispersed copper-ceria nanocatalysts were synthesized via appropriate tuning of a novel hydrothermal method. Various physicochemical techniques including electron paramagnetic resonance (EPR) spectroscopy, X-ray diffraction (XRD), N2 adsorption, scanning electron microscopy (SEM), Raman spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) were employed in the characterization of the synthesized materials, while all the catalysts were evaluated in the CO oxidation reaction. Moreover, discussion of the employed mechanism during hydrothermal route was provided. The observed catalytic activity in CO oxidation reaction was strongly dependent on the nanostructured morphology, oxygen vacancy concentration, and nature of atomically dispersed Cu2+ clusters.

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Cuo, Zhaxi, Dongdong Wang, Yan Gong, Feng Zhao, Haidi Liu i Yunfa Chen. "A Novel Porous Ceramic Membrane Supported Monolithic Cu-Doped Mn–Ce Catalysts for Benzene Combustion". Catalysts 9, nr 8 (30.07.2019): 652. http://dx.doi.org/10.3390/catal9080652.

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Porous ceramic membranes (PCMs) are considered as an efficient hot gas filtration material in industrial systems. Functionalization of the PCMs with high-efficiency catalysts for the abatement of volatile organic compounds (VOCs) during dust elimination is a promising way to purify the industrial exhaust gases. In this work, we prepared PCMs (porosity: 70%) in a facile sintering process and integrated Cu-doped Mn–Ce oxides into the PCMs as monolithic catalysts by the sol–gel method for benzene oxidation. Through this method, the catalysts are dispersed evenly throughout the PCMs with excellent adhesion, and the catalytic PCMs provided more active sites for the reactant gases during the catalytic reaction process compared to the powder catalysts. The physicochemical properties of PCMs and catalytic PCMs were characterized systematically, and the catalytic activities were measured in total oxidation of benzene. As a result, all the prepared catalytic PCMs exhibited high catalytic activity for benzene oxidation. Significantly, the monolithic catalyst of Cu0.2Mn0.6Ce0.2/PCMs obtained the lowest temperature for benzene conversion efficiency of 90% (T90) at 212 °C with a high gaseous hourly space velocity of 5000 h−1 and showed strong resistance to high humidity (90 vol.%, 20 °C) with long-term stability in continuous benzene stream, which is caused by abundant active adsorbed oxygen, more surficial oxygen vacancy, and lower-temperature reducibility.

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Damera, Thirupathi, Ramakanth Pagadala, Surjyakanta Rana i Sreekantha Babu Jonnalagadda. "A Concise Review of Multicomponent Reactions Using Novel Heterogeneous Catalysts under Microwave Irradiation". Catalysts 13, nr 7 (24.06.2023): 1034. http://dx.doi.org/10.3390/catal13071034.

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Multi-component reactions for the construction of heterocycles have been fascinated by microwave energy as an alternative technique of heating, owing to the advantages over traditional reflux methods. The heterogeneous catalysts contribute significantly towards recycling, harmless, easy filtration, catalyst preparation, more life span, abundance, and product yields. With novel and creative uses in organic and peptide synthesis, polymer chemistry, material sciences, nanotechnology, and biological processes, the usage of microwave energy has rapidly increased during the past 20 years. This article covers multicomponent reactions involving construction of chromenes, pyridines, pyrroles, triazoles, pyrazoles, tetrazoles, trans and cis julolidines using heterogeneous catalysts under microwave. It provides an overview of contemporary microwave-assisted heterogeneous catalytic reactions. Microwave chemistry is now an established technology with several advantages regarding reaction rate and production yield, improving energy savings as confirmed by many applications. Due to the widespread curiosity in medicinal chemistry, the heterogeneously catalysed construction of heterocycles under microwave irradiation is explored to reduce time and energy. By considering various aspects of economy, eco-friendly, and user-friendly factors, this review focuses on recent advances in the multi-component construction of heterocycles using heterogeneous catalysts under microwave irradiation. This review also discusses the benefits and limitations of reaction conditions and yields from the literature reports for the past five years.

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Palma, Vincenzo, Daniela Barba, Marta Cortese, Marco Martino, Simona Renda i Eugenio Meloni. "Microwaves and Heterogeneous Catalysis: A Review on Selected Catalytic Processes". Catalysts 10, nr 2 (18.02.2020): 246. http://dx.doi.org/10.3390/catal10020246.

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Since the late 1980s, the scientific community has been attracted to microwave energy as an alternative method of heating, due to the advantages that this technology offers over conventional heating technologies. In fact, differently from these, the microwave heating mechanism is a volumetric process in which heat is generated within the material itself, and, consequently, it can be very rapid and selective. In this way, the microwave-susceptible material can absorb the energy embodied in the microwaves. Application of the microwave heating technique to a chemical process can lead to both a reduction in processing time as well as an increase in the production rate, which is obtained by enhancing the chemical reactions and results in energy saving. The synthesis and sintering of materials by means of microwave radiation has been used for more than 20 years, while, future challenges will be, among others, the development of processes that achieve lower greenhouse gas (e.g., CO2) emissions and discover novel energy-saving catalyzed reactions. A natural choice in such efforts would be the combination of catalysis and microwave radiation. The main aim of this review is to give an overview of microwave applications in the heterogeneous catalysis, including the preparation of catalysts, as well as explore some selected microwave assisted catalytic reactions. The review is divided into three principal topics: (i) introduction to microwave chemistry and microwave materials processing; (ii) description of the loss mechanisms and microwave-specific effects in heterogeneous catalysis; and (iii) applications of microwaves in some selected chemical processes, including the preparation of heterogeneous catalysts.

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Bencivenni, Grazia, Nathalie Saraiva Rosa, Paolo Grieco, Malachi W. Gillick-Healy, Brian G. Kelly, Brendan Twamley i Mauro F. A. Adamo. "Quaternary Ammonium Salts Interact with Enolates and Sulfonates via Formation of Multiple +N-C-H Hydrogen Bonding Interactions". Catalysts 12, nr 7 (21.07.2022): 803. http://dx.doi.org/10.3390/catal12070803.

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We report herein sharp physical evidence, i.e., single-crystal X-ray diffraction and 1H-NMR spectral data, confirming that quaternary ammonium species interact with anions via a set of directional ion–dipole cooperative +N-C-H unusual H-bonding interactions and not via pure non-directional ionic electrostatic interactions. This finding, which has been often invoked by calculations, is herein substantiated by the preparation of two model compounds and an analysis of their X-ray crystal structures in the solid state and 1H-NMR spectra in solution. These observations are particularly pertinent for the rational design of novel catalyses and catalysts and providing guidance to an understanding of these species in solution and during asymmetric enantioselective catalysis.

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Hsueh, C. L., Y. H. Huang, C. C. Wang i C. Y. Chen. "Photooxidation of azo dye Reactive Black 5 using a novel supported iron oxide: heterogeneous and homogeneous approach". Water Science and Technology 53, nr 6 (1.03.2006): 195–201. http://dx.doi.org/10.2166/wst.2006.197.

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Photooxidation of azo dye Reactive Black 5 (RB5) by H2O2 was performed with a novel supported iron oxide in a batch reactor in the range of pH 2.5–6.0. The iron oxide was prepared through a fluidized-bed reactor (FBR) and much cheaper than the Nafion-based catalysts. Experimental results indicate that the iron oxide can significantly accelerate the degradation of RB5 under the irradiation of UVA light (λ=365 nm). An advantage of the catalyst is its long-term stability, which was confirmed through using the catalyst for multiple runs in the degradation of RB5. In addition, this study focused mainly on determining the proportions of homogeneous catalysis and heterogeneous catalysis in the batch reactor. Conclusively, although heterogeneous catalysis contributes primarily to the oxidation of RB5 during pH 4.5-6.0, the homogeneous catalysis is of increasing importance below pH 4.0 because of the Fe ions leaching from the catalyst to solution.

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