Relevant bibliographies by topics / Heterogeneous catalysts modification

Academic literature on the topic 'Heterogeneous catalysts modification'

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Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Heterogeneous catalysts modification"

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Mazaheri, Hoora, Hwai Chyuan Ong, Zeynab Amini, Haji Hassan Masjuki, M. Mofijur, Chia Hung Su, Irfan Anjum Badruddin, and T. M. Yunus Khan. "An Overview of Biodiesel Production via Calcium Oxide Based Catalysts: Current State and Perspective." Energies 14, no. 13 (July 1, 2021): 3950. http://dx.doi.org/10.3390/en14133950.

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Biodiesel is a clean, renewable, liquid fuel that can be used in existing diesel engines without modification as pure or blend. Transesterification (the primary process for biodiesel generation) via heterogeneous catalysis using low-cost waste feedstocks for catalyst synthesis improves the economics of biodiesel production. Heterogeneous catalysts are preferred for the industrial generation of biodiesel due to their robustness and low costs due to the easy separation and relatively higher reusability. Calcium oxides found in abundance in nature, e.g., in seashells and eggshells, are promising candidates for the synthesis of heterogeneous catalysts. However, process improvements are required to design productive calcium oxide-based catalysts at an industrial scale. The current work presents an overview of the biodiesel production advancements using calcium oxide-based catalysts (e.g., pure, supported, and mixed with metal oxides). The review discusses different factors involved in the synthesis of calcium oxide-based catalysts, and the effect of reaction parameters on the biodiesel yield of calcium oxide-based catalysis are studied. Further, the common reactor designs used for the heterogeneous catalysis using calcium oxide-based catalysts are explained. Moreover, the catalytic activity mechanism, challenges and prospects of the application of calcium oxide-based catalysts in biodiesel generation are discussed. The study of calcium oxide-based catalyst should continue to be evaluated for the potential of their application in the commercial sector as they remain the pivotal goal of these studies.
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Lemaire, Marc. "Heterogeneous asymmetric catalysis." Pure and Applied Chemistry 76, no. 3 (January 1, 2004): 679–88. http://dx.doi.org/10.1351/pac200476030679.

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Examples of enantioselective catalysts, including homogeneous supported catalysts and biphasic liquid/liquid, are described and compared. In the case of asymmetric hydride transfer, polythiourea was proven to be more efficient for ruthenium-catalyzed reduction of arylketones, although the iridium complexes gave rise to higher ee when using amino sulfonamide bound to a polystyrene matrix. In the case of asymmetric reduction, the modification of the binap allows the formation of a polymer that could be used as a catalyst precursor and exhibits enantioselectivities as high as observed in solution, but easier to separate and recycle. Bisoxazoline bound to silica particules could also be used in copper-catalyzed asymmetric Diels-Alder reaction and cyclopropanation with selectivities similar to that obtained in solution.
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Lokteva, Ekaterina S., Elena V. Golubina, Stanislav A. Kachevsky, Anara O. Turakulova, Valery V. Lunin, and Pietro Tundo. "Heterogeneous catalysts and process for reductive dechlorination of polychlorinated hydrocarbons." Pure and Applied Chemistry 79, no. 11 (January 1, 2007): 1905–14. http://dx.doi.org/10.1351/pac200779111905.

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The utilization and decomposition of chlorinated wastes without formation of dioxins are challenges of great environmental importance. In this work, the catalytic reductive methods of chlorinated organics processing are described, focusing on catalyst development. Pd-containing catalysts are improved by modification of supports [use of ultra dispersed diamond (UDD) or double oxides] or by dilution of Pd by not-noble metals (Fe, Ni, Cu). Both ways are effective for the processing of 1,3,5-trichlorobenzene (TCB) as a model of polychlorinated organics. The reasons for improvement of catalysts are discussed. The best catalysts were effectively used for hydrodechlorination (HDC) of hexachlorobenzene (HCB).
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Dobrescu, Gianina, Florica Papa, Razvan State, Monica Raciulete, Daniela Berger, Ioan Balint, and Niculae I. Ionescu. "Modified Catalysts and Their Fractal Properties." Catalysts 11, no. 12 (December 14, 2021): 1518. http://dx.doi.org/10.3390/catal11121518.

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Obtaining high-area catalysts is in demand in heterogeneous catalysis as it influences the ratio between the number of active surface sites and the number of total surface sites of the catalysts. From this point of view, fractal theory seems to be a suitable instrument to characterize catalysts’ surfaces. Moreover, catalysts with higher fractal dimensions will perform better in catalytic reactions. Modifying catalysts to increase their fractal dimension is a constant concern in heterogeneous catalysis. In this paper, scientific results related to oxide catalysts, such as lanthanum cobaltites and ferrites with perovskite structure, and nanoparticle catalysts (such as Pt, Rh, Pt-Cu, etc.) will be reviewed, emphasizing their fractal properties and the influence of their modification on both fractal and catalytic properties. Some of the methods used to compute the fractal dimension of the catalysts (micrograph fractal analysis and the adsorption isotherm method) and the computed fractal dimensions will be presented and discussed.
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Feng, Xuefeng, Zhi Gao, Longhui Xiao, Zhenqin Lai, and Feng Luo. "A Ni/Fe complex incorporated into a covalent organic framework as a single-site heterogeneous catalyst for efficient oxygen evolution reaction." Inorganic Chemistry Frontiers 7, no. 20 (2020): 3925–31. http://dx.doi.org/10.1039/d0qi00620c.

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Padmanaban, Sudakar, and Sungho Yoon. "Surface Modification of a MOF-based Catalyst with Lewis Metal Salts for Improved Catalytic Activity in the Fixation of CO2 into Polymers." Catalysts 9, no. 11 (October 26, 2019): 892. http://dx.doi.org/10.3390/catal9110892.

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The catalyst zinc glutarate (ZnGA) is widely used in the industry for the alternating copolymerization of CO2 with epoxides. However, the activity of this heterogeneous catalyst is restricted to the outer surface of its particles. Consequently, in the current study, to increase the number of active surface metal centers, ZnGA was treated with diverse metal salts to form heterogeneous, surface-modified ZnGA-Metal chloride (ZnGA-M) composite catalysts. These catalysts were found to be highly active for the copolymerization of CO2 and propylene oxide. Among the different metal salts, the catalysts treated with ZnCl2 (ZnGA-Zn) and FeCl3 (ZnGA-Fe) exhibited ~38% and ~25% increased productivities, respectively, compared to untreated ZnGA catalysts. In addition, these surface-modified catalysts are capable of producing high-molecular-weight polymers; thus, this simple and industrially viable surface modification method is beneficial from an environmental and industrial perspective.
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Trifan, Bianca, Javier Lasobras, Jaime Soler, Javier Herguido, and Miguel Menéndez. "Modifications in the Composition of CuO/ZnO/Al2O3 Catalyst for the Synthesis of Methanol by CO2 Hydrogenation." Catalysts 11, no. 7 (June 25, 2021): 774. http://dx.doi.org/10.3390/catal11070774.

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Renewable methanol, obtained from CO2 and hydrogen provided from renewable energy, was proposed to close the CO2 loop. In industry, methanol synthesis using the catalyst CuO/ZnO/Al2O3 occurs at a high pressure. We intend to make certain modification on the traditional catalyst to work at lower pressure, maintaining high selectivity. Therefore, three heterogeneous catalysts were synthesized by coprecipitation to improve the activity and the selectivity to methanol under mild conditions of temperature and pressure. Certain modifications on the traditional catalyst Cu/Zn/Al2O3 were employed such as the modification of the synthesis time and the addition of Pd as a dopant agent. The most efficient catalyst among those tested was a palladium-doped catalyst, 5% Pd/Cu/Zn/Al2O3. This had a selectivity of 64% at 210 °C and 5 bar.
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Duan, Haonan, Zanyao Niu, and Xiaoqi Yang. "Physical Properties of Cyclic Esters and its Application in Heterogeneous Electrocatalysis." Journal of Physics: Conference Series 2083, no. 2 (November 1, 2021): 022083. http://dx.doi.org/10.1088/1742-6596/2083/2/022083.

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Abstract Oxygen reduction is a key reaction in many energy conversion devices. Phosphorus-containing porous organic polymers not only have developed pores and surface structure, but also have strong adjustable modification and modification, so they have a wide application prospect in heterogeneous catalysis. At present, the preparation of phosphorus-containing porous organic polymers and their applications in heterogeneous catalysis have not been reviewed. in this paper, the research progress in this field in the past decade is summarized and reviewed. The synthetic methods of phosphorus-containing porous organic polymers are developing rapidly, including coupling Polycondensation, lithium salt-mediated Polycondensation, Friedel-Crafts Polycondensation, solvothermal olefin polymerization, Scholl Polycondensation, phenolic polymerization, aldehyde-amine condensation, phosphorization of polypyran salts and multistage polymerization. At the same time of briefly describing the mechanism of oxygen reduction reaction, combined with the research results of my own team, this paper focuses on the application of new porous materials (metal-organic framework MOF, conjugated microporous polymer CMP, etc.) in electrocatalysis. In view of the problems existing in the current electrocatalysts, the future research ideas are pointed out, including the use of advanced technical means to characterize the active sites of the catalysts in situ, based on the fact that there are a large number of phosphine ligands in the framework, phosphorus-containing porous organic polymers can be loaded with a series of metal compounds to make supported metal nanoparticles catalysts, or even monoatomic or unit point metal catalysts. The optimal structure of the catalyst was inversely calculated from the high active sites, and the preparation conditions of the materials were optimized. Under the guidance of theory and practice, a new type of electrocatalyst with high efficiency, stability, economy and environmental protection was developed on the premise of in-depth understanding of the mechanism of oxygen reduction reaction. Then an example is given to introduce the use of POPs to solve the basic scientific problems related to biomimetic catalysis, and show its great application potential. Finally, the challenges and opportunities in this emerging field are summarized and put forward.
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Kumar, Vijyendra, Titikshya Mohapatra, Sandeep Dharmadhikari, and Prabir Ghosh. "A Review Paper on Heterogeneous Fenton Catalyst: Types of Preparation, Modification Techniques, Factors Affecting the Synthesis, Characterization, and Application in the Wastewater Treatment." Bulletin of Chemical Reaction Engineering & Catalysis 15, no. 1 (September 10, 2019): 1–34. http://dx.doi.org/10.9767/bcrec.15.1.4374.1-34.

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This comprehensive review focuses on the different factors, modification in the synthesis method, characterization and application of heterogeneous catalyst in the wastewater treatment based on the Fenton process. The present review highlights the different catalyst preparation methods like wet impregnation method, hydrothermal method, sol-gel method, precipitation method and their application to treat different recalcitrant organic chemicals. Major heterogeneous catalyst synthesis methods were discussed with their excellent workability. The importance of modification through physical and chemical method was also reported. Different catalyst, pollutants and optimum parametric conditions available in the literature along with some relevant studies are summarized. The effect of factors like pH, calcination and some other modifiers on the synthesis and their efficiency in the wastewater treatment has been described. The important characterization of synthesized catalysts explaining their working efficiency has also been discussed. In the final section, the application of heterogeneous catalyst synthesized by different methods in the wastewater/effluent treatment has been investigated. The main aim of this review is to find out the influence of process parameters and catalytic method on degradation/decolorization of organic compounds present in industrial or synthetic wastewater. Copyright © 2020 BCREC Group. All rights reserved
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Wu, Bowen, Jian Chen, and Linping Qian. "Recent Advances in Heterogeneous Electroreduction of CO2 on Copper-Based Catalysts." Catalysts 12, no. 8 (August 4, 2022): 860. http://dx.doi.org/10.3390/catal12080860.

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Facing greenhouse effects and the rapid exhaustion of fossil fuel, CO2 electrochemical reduction presents a promising method of environmental protection and energy transformation. Low onset potential, large current density, high faradaic efficiency (FE), and long-time stability are required for industrial production, due to economic costs and energy consumption. This minireview showcases the recent progress in catalyst design and engineering technology in CO2 reduction reaction (CO2RR) on copper based-catalysts. We focus on strategies optimizing the performance of copper-based catalysts, such as single-atom catalysts, doping, surface modification, crystal facet engineering, etc., and reactor design including gas diffusion layer, membrane electrode assembly, etc., in enhancing target electroreduction products including methane, methanol, ethylene, and C2+ oxygenates. The determination of the correlation and the developed technology might be helpful for future applications in the industry.
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Dissertations / Theses on the topic "Heterogeneous catalysts modification"

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Griffiths, Stephen Paul. "Modification chemistry for chiral heterogeneous catalysts." Thesis, University of Hull, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390370.

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Ellis, Ieuan. "Interstitial modification of palladium for partial hydrogenation reactions." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:7c8c294c-0583-4a61-98e5-4c32d76cbf89.

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Heterogeneous catalysis is a key industrial process involved in the synthesis of nearly all chemicals currently produced. The environmental impact of these processes is huge so improvements must be made to current catalysts. Should a new material provide better yields at lower energy cost the benefits to both the industry and the planet are significant. There are many ways to change the behaviour of a catalyst, the addition of dopants, the selective blocking of active sites, and changing the strength of the support interaction to name a few. One technique that has become increasingly investigated is interstitial modification, the insertion of a light element into a metal lattice to change the metal's catalytic properties. The work presented in this thesis devises greener synthetic routes to the known Pd-interstitialB/C catalyst and investigates potential routes to a novel interstitial material, Pd-interstitialLi/C. Initially, successful verification of interstitial modification comes from the characteristic increase in palladium lattice parameter from 3.89 to 4.00 Å and the blocking of the β-hydride formation. Initial catalytic screening determines the synthetic route which yields the most active catalyst which subsequently undergoes thorough characterisation. The wealth of evidence generated confirms the interstitial location of lithium within the palladium lattice, as well as adding to the current understanding of the Pd-interstitialB/C material. EELS analysis on Pd-interstitialB is the closest to direct observation of boron within the palladium lattice to date. PDF on Pd-interstitialLi shows 13.7 % of the palladium octahedral interstitial sites are occupied by lithium. This is the first report of interstitial lithium within palladium to date. The effect of the interstitial modification on catalytic hydrogenation by two elements that have opposite effects on the surface electronics of the host palladium gives intriguing results. The effect on catalysis varies depending on the conditions investigated. This bank of hydrogenation data allows an informed choice as to which interstitial material would be best suited to the gas or liquid phase catalytic hydrogenation under investigation.
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Kolpin, Amy Louise. "A fundamental perspective on the effects of sulfur modification for transition metal nanocatalysts." Thesis, University of Oxford, 2014. https://ora.ox.ac.uk/objects/uuid:41d587f5-9704-4a3a-bb34-71bd0e91862b.

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The application of heterogeneous catalysts to industrial processes is a key factor in the synthesis of nearly all chemicals currently produced, however billions of pounds are lost every year due to unplanned reactor shutdowns and catalyst replacement as a result of catalytic deactivation processes. Poisoning of heterogeneous catalysts by sulfur compounds is a particularly prominent class of deactivation processes, affecting a wide range of catalytic materials and catalytic reactions, including the industrially-prominent Haber-Bosch process for the synthesis of ammonia and steam reforming of methane for the synthesis of hydrogen. However, while the effects of sulfur adsorption on catalytic behaviour are often unmistakably apparent, the fundamental interactions leading to these effects are not yet well understood. The work presented in this thesis uses a combination of models systems, novel and traditional characterization techniques, and methods of modifying catalyst geometric and electronic structure to approach the topic of sulfur poisoning from a fundamental perspective. Particular focus is placed on using selective decoration of active sites to develop a system of model hydrogenation reactions to relate changes in catalytic behaviour to changes in geometric and electronic structure. Application of these model reactions to investigate the sensitivities of palladium- and ruthenium-based catalytic systems to modification by sulfur shows contrasting effects for the two metals. While both systems exhibit similar geometric effects of modification, the palladium-based catalysts are far more sensitive than the ruthenium-based catalysts to modification of electronic structure. Additionally, controlled variation in particle size for the palladium-based catalysts demonstrates that catalytic behaviour is dominated by electronic structure for small nanoparticles and geometric structure for large nanoparticles. This leads small nanoparticles to show increased sensitivity to electronic modification effects resulting from sulfur adsorption. Ultimately, the research presented within this thesis provides a basis for the intelligent design of heterogeneous catalysts for improving tolerance for sulfur poisoning, and for utilizing the effects of sulfur modification to optimize catalytic activity and selectivity for the synthesis of fine chemicals.
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McKendry, Ian George. "THE SYNTHESIS AND MODIFICATION OF 2D MATERIALS FOR APPLICATION IN WATER OXIDATION CATALYSIS." Diss., Temple University Libraries, 2017. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/439189.

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Chemistry
Ph.D.
The unifying goal of this work is the design of a heterogeneous catalyst that can facilitate the energy intensive oxygen evolution reaction (OER) in water splitting, considered one of the ‘holy grails’ in catalytic science. In order for this process to be industrially feasible, an efficient catalyst composed of first row transition metal based materials must be used. To accomplish this, existing systems must be studied in order to determine which properties are important and subsequent creation and modification of new systems based on lessons learned must be employed. Birnessite, a 2D layered manganese dioxide, comprises the majority of the effort. In the studies leading to this work, this material was primarily studied by mineralogists with the majority focusing on structural characterization. However, the material’s moderate activity toward performing the OER has revived interest. In this work, we look to determine important species, the role dopants play in activity, and the function of the interlayer and surface chemistry. From these findings, an enhanced, earth abundant OER catalyst will be designed. We determine that Mn3+ in the system plays and important role in producing a catalytic species with large oxygen production capabilities. By increasing the amount of Mn3+ in the system via a simple comproportionation reaction by exposing the Mn4+ to Mn2+ ion, we increase the total turnover of birnessite 50-fold. Additionally, the addition of dopants to the system , both within and between the sheets, has a positive effect on the activity of birnessite. In particular, incorporation of cobalt into the lattice of birnessite brings the activity level on par to that of precious metal oxide catalysts due to the cobalt offering a deeper electron acceptor than in birnessite alone. In conjunction with these studies, the role of the interlayer species and catalyst confinement has demonstrated the ability to greatly enhance a catalyst’s ability to perform the OER by ordering and orienting the water around the active confined catalyst. Combining confinement effects with the cobalt-doped birnessite sheets resulted in further enhancement in the material’s OER capabilities. This system mimics that of an enzyme where the cobalt-doped birnessite sheets facilitate greater electron-hole transfer to the interlayer active site, where the confinement effects enhance electron transfer kinetics and water organization for O-O bond formation. Additionally, metal chalcogenide OER catalysts were explored with mattagamite phase cobalt pertelluride. Through the work, we determine the formation of a Te-Co-O heterostructure as the catalytically active phase, where the metallic nature of the cobalt pertelluride facilitates charge mobility between the electrode and catalyst’s cobalt oxide surface functioning as the active OER species.
Temple University--Theses
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Carson, Fabian. "Development of Metal–Organic Frameworks for Catalysis : Designing Functional and Porous Crystals." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-115819.

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Metal–organic frameworks, or MOFs, have emerged as a new class of porous materials made by linking metal and organic units. The easy preparation, structural and functional tunability, ultrahigh porosity, and enormous surface areas of MOFs have led to them becoming one of the fastest growing fields in chemistry. MOFs have potential applications in numerous areas such as clean energy, adsorption and separation processes, biomedicine, and sensing. One of the most promising areas of research with MOFs is heterogeneous catalysis. This thesis describes the design and synthesis of new, carboxylate-based MOFs for use as catalysts. These materials have been characterized using diffraction, spectroscopy, adsorption, and imaging techniques. The thesis has focused on preparing highly-stable MOFs for catalysis, using post-synthetic methods to modify the properties of these crystals, and applying a combination of characterization techniques to probe these complex materials. In the first part of this thesis, several new vanadium MOFs have been presented. The synthesis of MIL-88B(V), MIL-101(V), and MIL-47 were studied using ex situ techniques to gain insight into the synthesis–structure relationships. The properties of these materials have also been studied. In the second part, the use of MOFs as supports for metallic nanoparticles has been investigated. These materials, Pd@MIL-101–NH2(Cr) and Pd@MIL-88B–NH2(Cr), were used as catalysts for Suzuki–Miyaura and oxidation reactions, respectively. The effect of the base on the catalytic activity, crystallinity, porosity, and palladium distribution of Pd@MIL-101–NH2(Cr) was studied. In the final part, the introduction of transition-metal complexes into MOFs through different synthesis routes has been described. A ruthenium complex was grafted onto an aluminium MOF, MOF-253, and an iridium metallolinker was introduced into a zirconium MOF, UiO-68–2CH3. These materials were used as catalysts for alcohol oxidation and allylic alcohol isomerization, respectively.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 5: Manuscript.

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Jones, Simon Philip. "Influence of modifiers on Palladium based nanoparticles for room temperature formic acid decomposition." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:873277f2-c4f7-45b7-a16d-bba064e24bee.

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Heterogeneous catalysts form a highly important part of everyday life, ranging from the production of fertiliser enabling the growth of crops that sustain much of the world's population to the production of synthetic fuels. They constitute a key part of the chemical industry and contribute towards substantial economic and environmental benefits. Heterogeneous catalysts are also believed to have an important role to play in a future hydrogen economy, reducing our requirements for fossil fuels. To this end, formic acid has been proposed as a potential hydrogen storage material for small portable devices. Additionally, formic acid has historically been used as a probe molecule to study catalyst materials and recent developments in the knowledge of its decomposition pathways and the preferred sites of these reactions, establish a good foundation for further study. This work explores a range of novel modification techniques that alter the activity of Pd nanoparticles to decompose formic acid to H2 and CO2. The methods used are the addition of polymers, attaching various functional groups to the surface of the catalyst support and decoration of nanoparticles with sub-monolayer coverages of another metal. Using a range of characterisation methods including FTIR of an adsorbed CO probe, XRD and XPS coupled with computational modelling, it is found that these methods result in some significant electronic and/or geometric alterations to the Pd nanoparticles. For polymer modification, the nature of the pendent group is highly important in determining the effects of the polymer on the Pd particles, with all the tested polymers resulting in varying degrees of electronic donation to the Pd surface. The geometric modifications caused by the polymers also varied with pendent groups; with amine containing pendent groups found to selectively block low coordinate sites, preventing the undesired dehydration of formic acid which results in poisoning of the Pd catalyst by the resulting CO. Attachment of amine groups to the surface of metal oxide catalyst supports, is demonstrated to result in dramatic electronic promotional effects to the supported Pd nanoparticles, and when an amine polymer is attached to the support surface the geometric modification is again observed. Finally decoration of Pd nanoparticles with a sub-monolayer coverage of a second metal is examined, resulting in some similar electronic and geometric effects on Pd nanoparticle surfaces to those observed with polymer modification with corresponding changes in formic acid decomposition activity. Overall, a number of methods are displayed to tune the catalytic activity and selectivity of Pd nanoparticles for formic acid decomposition, resulting in catalysts with some of the highest reported TOF's at room temperature. These modification methods are believed to be potentially applicable to a wide range of other catalytic reactions that operate under mild conditions.
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Xu, Chao. "Imine/azo-linked microporous organic polymers : Design, synthesis and applications." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-121209.

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Microporous organic polymers (MOPs) are porous materials. Owing to their high surface area, tunable pore sizes and high physicochemical stability, they are studied for applications including gas capture and separation and heterogeneous catalysis. In this thesis, a series of imine/azo-linked MOPs were synthesized. The MOPs were examined as potential CO2 sorbents and as supports for heterogeneous catalysis. The MOPs were synthesized by Schiff base polycondensations and oxidative couplings. The porosities of the imine-linked MOPs were tunable and affected by a range of factors, such as the synthesis conditions, monomer lengths, monomer ratios. All the MOPs had ultramicropores and displayed relatively high CO2 uptakes and CO2-over-N2 selectivities at the CO2 concentrations relevant for post-combustion capture of CO2. Moreover, the ketimine-linked MOPs were moderately hydrophobic, which might increase their efficiency for CO2 capture and separation. The diverse synthesis routes and rich functionalities of MOPs allowed further post-modification to improve their performance in CO2 capture. A micro-/mesoporous polymer PP1-2, rich in aldehyde end groups, was post-synthetically modified by the alkyl amine tris(2-aminoethyl)amine (tren). The tethered amine moieties induced chemisorption of CO2 on the polymer, which was confirmed by the study of in situ infrared (IR) and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. As a result, the modified polymer PP1-2-tren had a large CO2 capacity and very high CO2-over-N2 selectivity at low partial pressures of CO2. Pd(II) species were incorporated in the selected MOPs by means of complexation or chemical bonding with the imine or azo groups. The Pd(II)-rich MOPs were tested as heterogeneous catalysts for various organic reactions. The porous Pd(II)-polyimine (Pd2+/PP-1) was an excellent co-catalyst in combination with chiral amine for cooperatively catalyzed and enantioselective cascade reactions. In addition, the cyclopalladated azo-linked MOP (Pd(II)/PP-2) catalyzed Suzuki and Heck coupling reactions highly efficiently.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Accepted. Paper 7: Manuscript.

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Yu, Bin. "Development of silver nanocatalyst for propylene selective oxidation reaction." Thesis, University of Oxford, 2018. http://ora.ox.ac.uk/objects/uuid:0f3f0556-bff1-4af1-bfe0-0e62b0425bff.

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Propylene is the second most important starting chemical in the petrochemical industry after ethylene. Unlike ethylene, propylene readily undergoes substitution reactions including polymerisation, oxidation, halogenation, hydrohalogenation, alkylation, hydration, oligomerization and hydroformylation, which lead to a wide variety of important downstream products. One of the principal uses of propylene is to produce key chemicals from selective oxidation. In 2016, the world annual production of propylene is about 94 million tonnes, and the global proportion used to produce selective oxidation product is over 18%. They constitute a key part of the chemical industry and contribute towards substantial economic benefits. The application of Ag based heterogeneous catalysts to selective propylene oxidation is a key factor in the synthesis of nearly all downstream chemicals, however billions of pounds are lost every year due to unplanned reactor shutdown, safety control and environment unfriendly emission control as a results of inefficiency catalytic selectivity and activity. Despite, both theoretical and experimental research works have been intensively involved, the fundamental reason leading to these effects are not yet well understood. The work presented in this thesis explores a range of novel modification techniques that alter the activity of Ag nanocatalysts for selective propylene oxidation, especially in propylene epoxidation. Particular focus is placed on developing surface modified Ag catalysts through morphology control, surface architecture engineering with another sublayer metal. Using a combination of modelling, novel and traditional materials characterisation methods, it is found that these modification result in some significant electronic and/or geometric alterations to the Ag nanoparticles surface. The Ag-Ag bond distance can be dramatically enlarged by exposing a high-index Ag surface or a core-shell structure with monolayer Ag shell. When interacting with molecular oxygen, the molecular oxygen adsorption and dissociation behaviour is sensitive to the geometric changes in Ag surface. This leads to an enhanced selectivity toward propylene epoxidation than combustion resulting from preventing a C-H bond cleavage. Finally, be creating atomically dispersed Ag on zeolite, a completely different interaction between molecular oxygen and single atom Ag were discovered comparing to on a extensive silver surface. This leads to the observation of an excitingly new propylene oxidation reaction producing ethanol and CO2 resulting from C=C bond cleavage. Overall, the research presented within this thesis demonstrated a number of methods for the intelligent design of novel heterogeneous Ag catalysts with remarkable activity and selectivity toward specific selective propylene oxidation. These modification methods are believed to be potentially applicable to a wide range of other catalytic reactions.
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Yildiz, Ceylan [Verfasser], and W. [Akademischer Betreuer] Kleist. "Post-synthetic modification of mixed-linker metal-organic frameworks for the design of heterogeneous single-site catalyst materials and their application in liquid phase oxidation reactions / Ceylan Yildiz ; Betreuer: W. Kleist." Karlsruhe : KIT-Bibliothek, 2020. http://d-nb.info/1209199149/34.

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FarisaRizki and 法芮莎. "Porously Composite Oxide with Sulfate Ions Modification as Heterogeneous Catalyst for Biodiesel Production via Esterification of Oleic Acid." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/02904429580633276689.

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Book chapters on the topic "Heterogeneous catalysts modification"

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Webb, Geoffrey. "Modification of Supported and Unsupported Nickel Catalysts by α-Amino and α-Hydroxy Acids for Chiral Reactions." In Chiral Reactions in Heterogeneous Catalysis, 61–74. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-1909-6_6.

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Margitfalvi, J. L., S. Göbölös, M. Hegedüs, and E. Talas. "Modification of NI/Al2O3 Hydrogenation Catalysts with Lead by Using controlled surface reactions." In Heterogeneous Catalysis and Fine Chemicals, Proceedings of an International Symposium, 145–52. Elsevier, 1988. http://dx.doi.org/10.1016/s0167-2991(09)60809-0.

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Kucherov, A. V., and A. A. Slinkin. "Zeolite modification by in-situ formed reactive gas-phase species. Preparation and properties of Mo-containing zeolites." In Preparation of Catalysts VII, Proceedings of the 7th International Symposium on Scientific Bases for the Preparation of Heterogeneous Catalysts, 567–76. Elsevier, 1998. http://dx.doi.org/10.1016/s0167-2991(98)80223-1.

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Sutormina, E. F., L. A. Isupova, N. A. Kulikovskaya, A. V. Kuznetsova, and E. I. Vovk. "The effect of 3d-cation modification on the properties of cordierite-like catalysts." In Scientific Bases for the Preparation of Heterogeneous Catalysts - Proceedings of the 10th International Symposium, Louvain-la-Neuve, Belgium, July 11-15, 2010, 343–46. Elsevier, 2010. http://dx.doi.org/10.1016/s0167-2991(10)75056-4.

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Holz, Laura I. V., Francisco J. A. Loureiro, Vanessa C. D. Graça, Allan J. M. Araújo, Diogo Mendes, Adélio Mendes, and Duncan P. Fagg. "Non-faradaic electrochemical modification of catalytic activity: A current overview." In Heterogeneous Catalysis, 515–30. Elsevier, 2022. http://dx.doi.org/10.1016/b978-0-323-85612-6.00019-x.

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Herry, S., O. Chassard, P. Blanchard, N. Frizi, P. Baranek, C. Lancelot, E. Payen, S. van Donk, J. P. Dath, and M. Rebeilleau. "Preparation of highly active gas oil HDS catalyst by modification of conventional oxidic precursor with 1,5-pentanediol." In Scientific Bases for the Preparation of Heterogeneous Catalysts - Proceedings of the 10th International Symposium, Louvain-la-Neuve, Belgium, July 11-15, 2010, 567–70. Elsevier, 2010. http://dx.doi.org/10.1016/s0167-2991(10)75110-7.

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Liotta, L. F., G. Di Carlo, F. Puleo, G. Pantaleo, and G. Deganello. "Mesoporous SBA-15 silica modified with cerium oxide: Effect of ceria loading on support modification." In Scientific Bases for the Preparation of Heterogeneous Catalysts - Proceedings of the 10th International Symposium, Louvain-la-Neuve, Belgium, July 11-15, 2010, 401–4. Elsevier, 2010. http://dx.doi.org/10.1016/s0167-2991(10)75070-9.

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Thakur, Abhinay, Shveta Sharma, and Ashish Kumar. "Preparation of Composite Metal-Organic Frameworks." In Emerging Applications and Implementations of Metal-Organic Frameworks, 1–12. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4760-1.ch001.

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Abstract:
In recent years, metal-organic frameworks (MOFs)-derived composites have emanated as a significant class of substantial materials with specific functional characteristics such as flexibility, high porosity, and diverse composition. Specific chemical modifications can also endow MOFs with specific functionality by offering the possibility of manufacturing all new generation of sensing devices. As on comparison with pure MOFs, the mix up of MOFs with matrix materials(e.g., metal nanoparticles, quantum dots, molecular species, enzymes, silica, and polymers) or functional species not only exhibits enhanced properties, but also widens its applications to modern field of heterogeneous catalysis, gas separation, potential hydrogen storage material and many others due to its high adsorption nature and excellent reversibility kinetics as in result reveals its various undefined attributes, such as reproducible syntheses, amenability to scale-up and chemical modification due to interactions of the functional matrix or species with the MOFs structures.
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Ye, Z. S. "40.1.8 Product Subclass 8: Piperazines." In Knowledge Updates 2021/2. Stuttgart: Georg Thieme Verlag KG, 2021. http://dx.doi.org/10.1055/sos-sd-140-00314.

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AbstractThe piperazine unit is widely distributed in natural products and life-saving small-molecule pharmaceuticals. It is the third most common nitrogen heterocycle occurring in pharmaceuticals approved by the U. S. Food and Drug Administration. This chapter covers strategies for the synthesis and transformations of piperazines, with both classical methods and recent developments reviewed. A major focus is on cyclization reactions such as intramolecular hydroaminations, multicomponent approaches, and routes from ethane-1,2-diamine substrates. Also discussed are approaches based on hydrogenation of (hydro)pyrazines by heterogeneous catalysis and by (asymmetric) homogeneous catalysis. Finally, a variety of transformations involving modification of a substituent on a piperazine ring are surveyed, including arylations, alkylations, and oxidations.
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Mateos-Pedrero, C., M. A. Soria, I. Rodríguez-Ramos, and A. Guerrero-Ruiz. "Modifications of porous stainless steel previous to the synthesis of Pd membranes." In Scientific Bases for the Preparation of Heterogeneous Catalysts - Proceedings of the 10th International Symposium, Louvain-la-Neuve, Belgium, July 11-15, 2010, 779–83. Elsevier, 2010. http://dx.doi.org/10.1016/s0167-2991(10)75159-4.

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Conference papers on the topic "Heterogeneous catalysts modification"

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Hartono, R., B. Mulia, M. Sahlan, T. S. Utami, Anondho Wijanarko, and Heri Hermansyah. "The modification of ion exchange heterogeneous catalysts for biodiesel synthesis." In RENEWABLE ENERGY TECHNOLOGY AND INNOVATION FOR SUSTAINABLE DEVELOPMENT: Proceedings of the International Tropical Renewable Energy Conference (i-TREC) 2016. Author(s), 2017. http://dx.doi.org/10.1063/1.4979236.

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Alshahidy, Balqees A., and Ammar S. Abbas. "Preparation and modification of 13X zeolite as a heterogeneous catalyst for esterification of oleic acid." In 2ND INTERNATIONAL CONFERENCE ON MATERIALS ENGINEERING & SCIENCE (IConMEAS 2019). AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0000171.

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You might also be interested in the extended bibliographies on the topic 'Heterogeneous catalysts modification' for particular source types:
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