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New Trends in Catalysis for Sustainable CO2 Conversion
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New Trends in Catalysis for Sustainable CO2 Conversion

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Environmental Catalysis".

Deadline for manuscript submissions: closed (30 June 2022) | Viewed by 46296

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editors

Prof. Dr. Javier Ereña

E-Mail Website
Guest Editor
Department of Chemical Engineering, University of the Basque Country UPV/EHU, P.O. Box 644, 48080 Bilbao, Spain
Interests: CO2 valorization; alternative fuels; syngas; catalysts and catalytic reactions; kinetic modeling; synthesis of methanol, dimethyl ether (DME), and hydrocarbons
Special Issues, Collections and Topics in MDPI journals
Dr. Ainara Ateka

E-Mail Website
Guest Editor
Department of Chemical Engineering, University of the Basque Country UPV/EHU, P.O. Box 644, 48080 Bilbao, Spain
Interests: CO2 valorization; alternative fuels; syngas; catalysts and catalytic reactions; kinetic modeling; synthesis of methanol, dimethyl ether (DME), and hydrocarbons
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Over the past few decades, there have been many advances in the world, leading to the improvement of life quality. Due to demographic and industrial growth, consumption has increased, as well as the amount of wastes and contaminants. Today, global warming and climate change are mainly attributed to the emission of anthropogenic greenhouse gases, with carbon dioxide (CO2) being the most relevant one, due to the huge amount of emissions of this gas to the atmosphere (mainly derived from the consumption of fossil fuels).

Carbon capture and storage (CCS) is a physical process which consists of separating the CO2 (emitted by the industry and by the combustion processes for energy generation) and transporting it to a geological storage to isolate it from the atmosphere in the long term. However, the most promising routes for CO2 mitigation are those that use catalysts and chemical processes for valorization. By applying specific catalysts and suitable operating conditions, CO2 molecules react with other components to form longer chains (i.e., hydrocarbons). Accordingly, efforts should be made to catalytically valorize CO2 (alone or being co-fed with syngas), as an alternative way for reducing greenhouse gas emissions and obtaining high-value fuels and chemicals.

Carbon capture and utilization (CCU) is a developing field with significant demand for research in the following aspects:

  • Development of new catalysts, catalytic routes, and technologies for CO2 valorization;
  • Study of new processes for obtaining fuels and chemicals from CO2;
  • Optimization of the catalyst and the reaction conditions for the process;
  • Steps further on advanced processes for improving the amount of CO2 fed into the reactor (either alone or co-fed with syngas) and the yield of products.

Dr. Javier Ereña
Dr. Ainara Ateka Bilbao
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Catalysts is an international peer-reviewed open access monthly journal published by MDPI.

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

Keywords

  • catalytic processes for CO2 transformation
  • CO2 valorization
  • carbon capture and storage (CCS)
  • carbon capture and utilization (CCU)
  • climate change mitigation
  • synthesis of fuels and chemicals
  • syngas

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Published Papers (14 papers)

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Editorial

Jump to: Research, Review

4 pages, 195 KiB  
Editorial
New Trends in Catalysis for Sustainable CO2 Conversion
by Javier Ereña and Ainara Ateka
Catalysts 2022, 12(11), 1300; https://doi.org/10.3390/catal12111300 - 23 Oct 2022
Viewed by 1198
Abstract
Over the past few decades, there have been many advances in the world, leading to improvements in quality of life [...] Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)

Research

Jump to: Editorial, Review

14 pages, 2937 KiB  
Article
The Conversion of Waste Biomass into Carbon-Supported Iron Catalyst for Syngas to Clean Liquid Fuel Production
by Muhammad Amin, Saleem Munir, Naseem Iqbal, Saikh Mohammad Wabaidur and Amjad Iqbal
Catalysts 2022, 12(10), 1234; https://doi.org/10.3390/catal12101234 - 14 Oct 2022
Cited by 11 | Viewed by 2006
Abstract
Syngas has been utilized in the production of chemicals and fuels, as well as in the creation of electricity. Feedstock impurities, such as nitrogen, sulfur, chlorine, and ash, in syngas have a negative impact on downstream processes. Fischer–Tropsch synthesis is a process that [...] Read more.
Syngas has been utilized in the production of chemicals and fuels, as well as in the creation of electricity. Feedstock impurities, such as nitrogen, sulfur, chlorine, and ash, in syngas have a negative impact on downstream processes. Fischer–Tropsch synthesis is a process that relies heavily on temperature to increase the production of liquid fuels (FTS). In this study, waste biomass converted into activated carbon and then a carbon-supported iron-based catalyst was prepared. The catalyst at 200 °C and 350 °C was used to investigate the influence of temperature on the subsequent application of syngas to liquid fuels. Potassium (K) was used as a structural promoter in the Fe-C catalyst to boost catalyst activity and structural stability (Fe-C-K). Low temperatures (200 °C) cause 60% and 80% of diesel generation, respectively, without and with potassium promoter. At high temperatures (350 °C), the amount of gasoline produced is 36% without potassium promoter, and 72% with promoter. Iron carbon-supported catalysts with potassium promoter increase gasoline conversion from 36.4% (Fe-C) to 72.5% (Fe-C-K), and diesel conversion from 60.8% (Fe-C) to 80.0% (Fe-C-K). As seen by SEM pictures, iron particles with potassium promoter were found to be equally distributed on the surface of activated carbon. Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)
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13 pages, 6918 KiB  
Article
Hydrogenation of CO2 on Nanostructured Cu/FeOx Catalysts: The Effect of Morphology and Cu Load on Selectivity
by Karolína Simkovičová, Muhammad I. Qadir, Naděžda Žilková, Joanna E. Olszówka, Pavel Sialini, Libor Kvítek and Štefan Vajda
Catalysts 2022, 12(5), 516; https://doi.org/10.3390/catal12050516 - 04 May 2022
Cited by 3 | Viewed by 2383
Abstract
The aim of this work was to study the influence of copper content and particle morphology on the performance of Cu/FeOx catalysts in the gas-phase conversion of CO2 with hydrogen. All four investigated catalysts with a copper content between 0 and [...] Read more.
The aim of this work was to study the influence of copper content and particle morphology on the performance of Cu/FeOx catalysts in the gas-phase conversion of CO2 with hydrogen. All four investigated catalysts with a copper content between 0 and 5 wt% were found highly efficient, with CO2 conversion reaching 36.8%, and their selectivity towards C1 versus C2-C4, C2-C4=, and C5+ products was dependent on catalyst composition, morphology, and temperature. The observed range of products is different from those observed for catalysts with similar composition but synthesized using other precursors and chemistries, which yield different morphologies. The findings presented in this paper indicate potential new ways of tuning the morphology and composition of iron-oxide-based particles, ultimately yielding catalyst compositions and morphologies with variable catalytic performances. Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)
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21 pages, 11233 KiB  
Article
Controlled Transition Metal Nucleated Growth of Carbon Nanotubes by Molten Electrolysis of CO2
by Xinye Liu, Gad Licht, Xirui Wang and Stuart Licht
Catalysts 2022, 12(2), 137; https://doi.org/10.3390/catal12020137 - 22 Jan 2022
Cited by 9 | Viewed by 5074
Abstract
The electrolysis of CO2 in molten carbonate has been introduced as an alternative mechanism to synthesize carbon nanomaterials inexpensively at high yield. Until recently, CO2 was thought to be unreactive, making its removal a challenge. CO2 is the main cause [...] Read more.
The electrolysis of CO2 in molten carbonate has been introduced as an alternative mechanism to synthesize carbon nanomaterials inexpensively at high yield. Until recently, CO2 was thought to be unreactive, making its removal a challenge. CO2 is the main cause of anthropogenic global warming and its utilization and transformation into a stable, valuable material provides an incentivized pathway to mitigate climate change. This study focuses on controlled electrochemical conditions in molten lithium carbonate to split CO2 absorbed from the atmosphere into carbon nanotubes (CNTs), and into various macroscopic assemblies of CNTs, which may be useful for nano-filtration. Different CNT morphologies were prepared electrochemically by variation of the anode and cathode composition and architecture, variation of the electrolyte composition pre-electrolysis processing, and variation of the current application and current density. Individual CNT morphologies’ structures and the CNT molten carbonate growth mechanisms are explored using SEM (scanning electron microscopy), TEM (transmission electron micrsocopy), HAADF (high angle annular dark field), EDX (energy dispersive xray), X-ray diffraction), and Raman methods. The principle commercial technology for CNT production had been chemical vapor deposition, which is an order of magnitude more expensive, generally requires metallo-organics, rather than CO2 as reactants, and can be highly energy and CO2 emission intensive (carries a high carbon positive, rather than negative, footprint). Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)
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28 pages, 18351 KiB  
Article
Controlled Growth of Unusual Nanocarbon Allotropes by Molten Electrolysis of CO2
by Xinye Liu, Gad Licht, Xirui Wang and Stuart Licht
Catalysts 2022, 12(2), 125; https://doi.org/10.3390/catal12020125 - 21 Jan 2022
Cited by 12 | Viewed by 3164
Abstract
This study describes a world of new carbon “fullerene” allotropes that may be synthesized by molten carbonate electrolysis using greenhouse CO2 as the reactant. Beyond the world of conventional diamond, graphite and buckyballs, a vast array of unique nanocarbon structures exist. Until [...] Read more.
This study describes a world of new carbon “fullerene” allotropes that may be synthesized by molten carbonate electrolysis using greenhouse CO2 as the reactant. Beyond the world of conventional diamond, graphite and buckyballs, a vast array of unique nanocarbon structures exist. Until recently, CO2 was thought to be unreactive. Here, we show that CO2 can be transformed into distinct nano-bamboo, nano-pearl, nano-dragon, solid and hollow nano-onion, nano-tree, nano-rod, nano-belt and nano-flower morphologies of carbon. The capability to produce these allotropes at high purity by a straightforward electrolysis, analogous to aluminum production splitting of aluminum oxide, but instead nanocarbon production by splitting CO2, opens an array of inexpensive unique materials with exciting new high strength, electrical and thermal conductivity, flexibility, charge storage, lubricant and robustness properties. Commercial production technology of nanocarbons had been chemical vapor deposition, which is ten-fold more expensive, generally requires metallo-organics reactants and has a highly carbon-positive rather than carbon-negative footprint. Different nanocarbon structures were prepared electrochemically by variation of anode and cathode composition and architecture, electrolyte composition, pre-electrolysis processing and current ramping and current density. Individual allotrope structures and initial growth mechanisms are explored by SEM, TEM, HAADF EDX, XRD and Raman spectroscopy. Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)
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16 pages, 7707 KiB  
Article
CO2 Reduction to Valuable Chemicals on TiO2-Carbon Photocatalysts Deposited on Silica Cloth
by Antoni Waldemar Morawski, Katarzyna Ćmielewska, Kordian Witkowski, Ewelina Kusiak-Nejman, Iwona Pełech, Piotr Staciwa, Ewa Ekiert, Daniel Sibera, Agnieszka Wanag, Marcin Gano and Urszula Narkiewicz
Catalysts 2022, 12(1), 31; https://doi.org/10.3390/catal12010031 - 28 Dec 2021
Cited by 8 | Viewed by 1939
Abstract
A new photocatalyst for CO2 reduction has been presented. The photocatalyst was prepared from a combination of a commercial P25 with a mesopore structure and carbon spheres with a microporous structure with high CO2 adsorption capacity. Then, the obtained hybrid TiO [...] Read more.
A new photocatalyst for CO2 reduction has been presented. The photocatalyst was prepared from a combination of a commercial P25 with a mesopore structure and carbon spheres with a microporous structure with high CO2 adsorption capacity. Then, the obtained hybrid TiO2-carbon sphere photocatalysts were deposited on a glass fiber fabric. The combined TiO2-carbon spheres/silica cloth photocatalysts showed higher efficiency in the two-electron CO2 reduction towards CO than in the eight-electron reaction to methane. The 0.5 g graphitic carbon spheres combined with 1 g of TiO2 P25 resulted in almost 100% selectivity to CO. From a practical point of view, this is promising as it economically eliminates the need to separate CO from the gas mixture after the reaction, which also contains CH4 and H2. Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)
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14 pages, 5141 KiB  
Article
The Effect of Si on CO2 Methanation over Ni-xSi/ZrO2 Catalysts at Low Temperature
by Li Li, Ye Wang, Qing Zhao and Changwei Hu
Catalysts 2021, 11(1), 67; https://doi.org/10.3390/catal11010067 - 05 Jan 2021
Cited by 7 | Viewed by 2148
Abstract
A series of Ni-xSi/ZrO2 (x = 0, 0.1, 0.5, 1 wt%, the controlled contents of Si) catalysts with a controlled nickel content of 10 wt% were prepared by the co-impregnation method with ZrO2 as support and Si as a promoter. The [...] Read more.
A series of Ni-xSi/ZrO2 (x = 0, 0.1, 0.5, 1 wt%, the controlled contents of Si) catalysts with a controlled nickel content of 10 wt% were prepared by the co-impregnation method with ZrO2 as support and Si as a promoter. The effect of different amounts of Si on the catalytic performance was investigated for CO2 methanation with the stoichiometric H2/CO2 molar ratio (4/1). The catalysts were characterized by BET, XRF, H2-TPR, H2-TPD, H2-chemisorption, CO2-TPD, XRD, TEM, XPS, and TG-DSC. It was found that adding the appropriate amount of Si could improve the catalytic performance of Ni/ZrO2 catalyst at a low reaction temperature (250 °C). Among all the catalysts studied, the Ni-0.1Si/ZrO2 catalyst showed the highest catalytic activity, with H2 and CO2 conversion of 73.4% and 72.5%, respectively and the yield of CH4 was 72.2%. Meanwhile, the catalyst showed high stability and no deactivation within a 10 h test. Adding the appropriate amount of Si could enhance the interaction between Ni and ZrO2, and increase the Ni dispersion, the amounts of active sites including surface Ni0, oxygen vacancies, and strong basic sites on the catalyst surface. These might be the reasons for the high activity and selectivity of the Ni-0.1Si/ZrO2 catalyst. Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)
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13 pages, 2693 KiB  
Article
Enhanced Carbon Dioxide Decomposition Using Activated SrFeO3−δ
by Jaeyong Sim, Sang-Hyeok Kim, Jin-Yong Kim, Ki Bong Lee, Sung-Chan Nam and Chan Young Park
Catalysts 2020, 10(11), 1278; https://doi.org/10.3390/catal10111278 - 03 Nov 2020
Cited by 3 | Viewed by 2458
Abstract
Today, climate change caused by global warming has become a worldwide problem with increasing greenhouse gas (GHG) emissions. Carbon capture and storage technologies have been developed to capture carbon dioxide (CO2); however, CO2 storage and utilization technologies are relatively less [...] Read more.
Today, climate change caused by global warming has become a worldwide problem with increasing greenhouse gas (GHG) emissions. Carbon capture and storage technologies have been developed to capture carbon dioxide (CO2); however, CO2 storage and utilization technologies are relatively less developed. In this light, we have reported efficient CO2 decomposition results using a nonperovskite metal oxide, SrFeCo0.5Ox, in a continuous-flow system. In this study, we report enhanced efficiency, reliability under isothermal conditions, and catalytic reproducibility through cyclic tests using SrFeO3−δ. This ferrite needs an activation process, and 3.5 vol% H2/N2 was used in this experiment. Activated oxygen-deficient SrFeO3−δ can decompose CO2 into carbon monoxide (CO) and carbon (C). Although SrFeO3−δ is a well-known material in different fields, no studies have reported its use in CO2 decomposition applications. The efficiency of CO2 decomposition using SrFeO3−δ reached ≥90%, and decomposition (≥80%) lasted for approximately 170 min. We also describe isothermal and cyclic experimental data for realizing commercial applications. We expect that these results will contribute to the mitigation of GHG emissions. Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)
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14 pages, 1768 KiB  
Article
Efficient Electrochemical Reduction of CO2 to CO in Ionic Liquid/Propylene Carbonate Electrolyte on Ag Electrode
by Fengyang Ju, Jinjin Zhang and Weiwei Lu
Catalysts 2020, 10(10), 1102; https://doi.org/10.3390/catal10101102 - 24 Sep 2020
Cited by 7 | Viewed by 3416
Abstract
The electrochemical reduction of CO2 is a promising way to recycle it to produce value-added chemicals and fuels. However, the requirement of high overpotential and the low solubility of CO2 in water severely limit their efficient conversion. To overcome these problems, [...] Read more.
The electrochemical reduction of CO2 is a promising way to recycle it to produce value-added chemicals and fuels. However, the requirement of high overpotential and the low solubility of CO2 in water severely limit their efficient conversion. To overcome these problems, in this work, a new type of electrolyte solution constituted by ionic liquids and propylene carbonate was used as the cathodic solution, to study the conversion of CO2 on an Ag electrode. The linear sweep voltammetry (LSV), Tafel characterization and electrochemical impedance spectroscopy (EIS) were used to study the catalytic effect and the mechanism of ionic liquids in electrochemical reduction of CO2. The LSV and Tafel characterization indicated that the chain length of 1-alkyl-3-methyl imidazolium cation had strong influences on the catalytic performance for CO2 conversion. The EIS analysis showed that the imidazolium cation that absorbed on the Ag electrode surface could stabilize the anion radical (CO2•−), leading to the enhanced efficiency of CO2 conversion. At last, the catalytic performance was also evaluated, and the results showed that Faradaic efficiency for CO as high as 98.5% and current density of 8.2 mA/cm2 could be achieved at −1.9 V (vs. Fc/Fc+). Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)
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20 pages, 4938 KiB  
Article
Synthesis and Characterization of p-n Junction Ternary Mixed Oxides for Photocatalytic Coprocessing of CO2 and H2O
by Davide M. S. Marcolongo, Francesco Nocito, Nicoletta Ditaranto, Michele Aresta and Angela Dibenedetto
Catalysts 2020, 10(9), 980; https://doi.org/10.3390/catal10090980 - 31 Aug 2020
Cited by 7 | Viewed by 2625
Abstract
In the present paper, we report the synthesis and characterization of both binary (Cu2O, Fe2O3, and In2O3) and ternary (Cu2O-Fe2O3 and Cu2O-In2O3) [...] Read more.
In the present paper, we report the synthesis and characterization of both binary (Cu2O, Fe2O3, and In2O3) and ternary (Cu2O-Fe2O3 and Cu2O-In2O3) transition metal mixed-oxides that may find application as photocatalysts for solar driven CO2 conversion into energy rich species. Two different preparation techniques (High Energy Milling (HEM) and Co-Precipitation (CP)) are compared and materials properties are studied by means of a variety of characterization and analytical techniques UV-Visible Diffuse Reflectance Spectroscopy (UV-VIS DRS), X-ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Energy Dispersive X-Ray spectrometry (EDX). Appropriate data elaboration methods are used to extract materials bandgap for Cu2O@Fe2O3 and Cu2O@In2O3 prepared by HEM and CP, and foresee whether the newly prepared semiconductor mixed oxides pairs are useful for application in CO2-H2O coprocessing. The experimental results show that the synthetic technique influences the photoactivity of the materials that can correctly be foreseen on the basis of bandgap experimentally derived. Of the mixed oxides prepared and described in this work, only Cu2O@In2O3 shows positive results in CO2-H2O photo-co-processing. Preliminary results show that the composition and synthetic methodologies of mixed-oxides, the reactor geometry, the way of dispersing the photocatalyst sample, play a key role in the light driven reaction of CO2–H2O. This work is a rare case of full characterization of photo-materials, using UV-Visible DRS, XPS, XRD, TEM, EDX for the surface and bulk analytical characterization. Surface composition may not be the same of the bulk composition and plays a key role in photocatalysts behavior. We show that a full material knowledge is necessary for the correct forecast of their photocatalytic behavior, inferred from experimentally determined bandgaps. Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)
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14 pages, 6565 KiB  
Article
Evaluation of CO2 Hydrogenation in a Modular Fixed-Bed Reactor Prototype
by Heather D. Willauer, Matthew J. Bradley, Jeffrey W. Baldwin, Joseph J. Hartvigsen, Lyman Frost, James R. Morse, Felice DiMascio, Dennis R. Hardy and David J. Hasler
Catalysts 2020, 10(9), 970; https://doi.org/10.3390/catal10090970 - 26 Aug 2020
Cited by 6 | Viewed by 3087
Abstract
Low-cost iron-based CO2 hydrogenation catalysts have shown promise as a viable route to the production of value-added hydrocarbon building blocks. It is envisioned that these hydrocarbons will be used to augment industrial chemical processes and produce drop-in replacement operational fuel. To this [...] Read more.
Low-cost iron-based CO2 hydrogenation catalysts have shown promise as a viable route to the production of value-added hydrocarbon building blocks. It is envisioned that these hydrocarbons will be used to augment industrial chemical processes and produce drop-in replacement operational fuel. To this end, the U.S. Naval Research Laboratory (NRL) has been designing, testing, modeling, and evaluating CO2 hydrogenation catalysts in a laboratory-scale fixed-bed environment. To transition from the laboratory to a commercial process, the catalyst viability and performance must be evaluated at scale. The performance of a Macrolite®-supported iron-based catalyst in a commercial-scale fixed-bed modular reactor prototype was evaluated under different reactor feed rates and product recycling conditions. CO2 conversion increased from 26% to as high as 69% by recycling a portion of the product stream and CO selectivity was greatly reduced from 45% to 9% in favor of hydrocarbon production. In addition, the catalyst was successfully regenerated for optimum performance. Catalyst characterization by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), along with modeling and kinetic analysis, highlighted the potential challenges and benefits associated with scaling-up catalyst materials and processes for industrial implementation. Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)
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Review

Jump to: Editorial, Research

41 pages, 9623 KiB  
Review
Utilization of CO2-Available Organocatalysts for Reactions with Industrially Important Epoxides
by Tomáš Weidlich and Barbora Kamenická
Catalysts 2022, 12(3), 298; https://doi.org/10.3390/catal12030298 - 06 Mar 2022
Cited by 16 | Viewed by 4086
Abstract
Recent knowledge in chemistry has enabled the material utilization of greenhouse gas (CO2) for the production of organic carbonates using mild reaction conditions. Organic carbonates, especially cyclic carbonates, are applicable as green solvents, electrolytes in batteries, feedstock for fine chemicals and [...] Read more.
Recent knowledge in chemistry has enabled the material utilization of greenhouse gas (CO2) for the production of organic carbonates using mild reaction conditions. Organic carbonates, especially cyclic carbonates, are applicable as green solvents, electrolytes in batteries, feedstock for fine chemicals and monomers for polycarbonate production. This review summarizes new developments in the ring opening of epoxides with subsequent CO2-based formation of cyclic carbonates. The review highlights recent and major developments for sustainable CO2 conversion from 2000 to the end of 2021 abstracted by Web of Science. The syntheses of epoxides, especially from bio-based raw materials, will be summarized, such as the types of raw material (vegetable oils or their esters) and the reaction conditions. The aim of this review is also to summarize and to compare the types of homogeneous non-metallic catalysts. The three reaction mechanisms for cyclic carbonate formation are presented, namely activation of the epoxide ring, CO2 activation and dual activation. Usually most effective catalysts described in the literature consist of powerful sources of nucleophile such as onium salt, of hydrogen bond donors and of tertiary amines used to combine epoxide activation for facile epoxide ring opening and CO2 activation for the subsequent smooth addition reaction and ring closure. The most active catalytic systems are capable of activating even internal epoxides such as epoxidized unsaturated fatty acid derivatives for the cycloaddition of CO2 under relatively mild conditions. In case of terminal epoxides such as epichlorohydrin, the effective utilization of diluted sources of CO2 such as flue gas is possible using the most active organocatalysts even at ambient pressure. Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)
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39 pages, 18470 KiB  
Review
Recent Advances in the Mitigation of the Catalyst Deactivation of CO2 Hydrogenation to Light Olefins
by Daniel Weber, Tina He, Matthew Wong, Christian Moon, Axel Zhang, Nicole Foley, Nicholas J. Ramer and Cheng Zhang
Catalysts 2021, 11(12), 1447; https://doi.org/10.3390/catal11121447 - 28 Nov 2021
Cited by 14 | Viewed by 4070
Abstract
The catalytic conversion of CO2 to value-added chemicals and fuels has been long regarded as a promising approach to the mitigation of CO2 emissions if green hydrogen is used. Light olefins, particularly ethylene and propylene, as building blocks for polymers and [...] Read more.
The catalytic conversion of CO2 to value-added chemicals and fuels has been long regarded as a promising approach to the mitigation of CO2 emissions if green hydrogen is used. Light olefins, particularly ethylene and propylene, as building blocks for polymers and plastics, are currently produced primarily from CO2-generating fossil resources. The identification of highly efficient catalysts with selective pathways for light olefin production from CO2 is a high-reward goal, but it has serious technical challenges, such as low selectivity and catalyst deactivation. In this review, we first provide a brief summary of the two dominant reaction pathways (CO2-Fischer-Tropsch and MeOH-mediated pathways), mechanistic insights, and catalytic materials for CO2 hydrogenation to light olefins. Then, we list the main deactivation mechanisms caused by carbon deposition, water formation, phase transformation and metal sintering/agglomeration. Finally, we detail the recent progress on catalyst development for enhanced olefin yields and catalyst stability by the following catalyst functionalities: (1) the promoter effect, (2) the support effect, (3) the bifunctional composite catalyst effect, and (4) the structure effect. The main focus of this review is to provide a useful resource for researchers to correlate catalyst deactivation and the recent research effort on catalyst development for enhanced olefin yields and catalyst stability. Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)
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25 pages, 7145 KiB  
Review
The Role of CO2 as a Mild Oxidant in Oxidation and Dehydrogenation over Catalysts: A Review
by Sheikh Tareq Rahman, Jang-Rak Choi, Jong-Hoon Lee and Soo-Jin Park
Catalysts 2020, 10(9), 1075; https://doi.org/10.3390/catal10091075 - 17 Sep 2020
Cited by 14 | Viewed by 6268
Abstract
Carbon dioxide (CO2) is widely used as an enhancer for industrial applications, enabling the economical and energy-efficient synthesis of a wide variety of chemicals and reducing the CO2 levels in the environment. CO2 has been used as an enhancer [...] Read more.
Carbon dioxide (CO2) is widely used as an enhancer for industrial applications, enabling the economical and energy-efficient synthesis of a wide variety of chemicals and reducing the CO2 levels in the environment. CO2 has been used as an enhancer in a catalytic system which has revived the exploitation of energy-extensive reactions and carry chemical products. CO2 oxidative dehydrogenation is a greener alternative to the classical dehydrogenation method. The availability, cost, safety, and soft oxidizing properties of CO2, with the assistance of appropriate catalysts at an industrial scale, can lead to breakthroughs in the pharmaceutical, polymer, and fuel industries. Thus, in this review, we focus on several applications of CO2 in oxidation and oxidative dehydrogenation systems. These processes and catalytic technologies can reduce the cost of utilizing CO2 in chemical and fuel production, which may lead to commercial applications in the imminent future. Full article
(This article belongs to the Special Issue New Trends in Catalysis for Sustainable CO2 Conversion)
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