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Michiels R, Gerrits N, Neyts E, Bogaerts A. Plasma Catalysis Modeling: How Ideal Is Atomic Hydrogen for Eley-Rideal? THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2024; 128:11196-11209. [PMID: 39015417 PMCID: PMC11247482 DOI: 10.1021/acs.jpcc.4c02193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 06/20/2024] [Accepted: 06/25/2024] [Indexed: 07/18/2024]
Abstract
Plasma catalysis is an emerging technology, but a lot of questions about the underlying surface mechanisms remain unanswered. One of these questions is how important Eley-Rideal (ER) reactions are, next to Langmuir-Hinshelwood reactions. Most plasma catalysis kinetic models predict ER reactions to be important and sometimes even vital for the surface chemistry. In this work, we take a critical look at how ER reactions involving H radicals are incorporated in kinetic models describing CO2 hydrogenation and NH3 synthesis. To this end, we construct potential energy surface (PES) intersections, similar to elbow plots constructed for dissociative chemisorption. The results of the PES intersections are in agreement with ab initio molecular dynamics (AIMD) findings in literature while being computationally much cheaper. We find that, for the reactions studied here, adsorption is more probable than a reaction via the hot atom (HA) mechanism, which in turn is more probable than a reaction via the ER mechanism. We also conclude that kinetic models of plasma-catalytic systems tend to overestimate the importance of ER reactions. Furthermore, as opposed to what is often assumed in kinetic models, the choice of catalyst will influence the ER reaction probability. Overall, the description of ER reactions is too much "ideal" in models. Based on our findings, we make a number of recommendations on how to incorporate ER reactions in kinetic models to avoid overestimation of their importance.
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Affiliation(s)
- Roel Michiels
- Research
group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, Wilrijk,Antwerp BE-2610, Belgium
| | - Nick Gerrits
- Research
group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, Wilrijk,Antwerp BE-2610, Belgium
- Leiden
Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, Leiden 2300 RA, The Netherlands
| | - Erik Neyts
- Research
group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, Wilrijk,Antwerp BE-2610, Belgium
| | - Annemie Bogaerts
- Research
group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, Wilrijk,Antwerp BE-2610, Belgium
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Lefferts L. Leveraging Expertise in Thermal Catalysis to Understand Plasma Catalysis. Angew Chem Int Ed Engl 2024; 63:e202305322. [PMID: 38279548 DOI: 10.1002/anie.202305322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Indexed: 01/28/2024]
Abstract
Best practices in testing heterogeneous catalysts are translated to plasma-catalytic experiments. Independent determination of plasma-catalytic and plasma-chemical contributions is essential. Non-porous catalyst particles are preferred because active sites inside sub-micron pores cannot contribute. Temperature variation is needed to determine kinetics, despite the complexity of thermal effects in plasma. Rigorous checks on catalyst deactivation and mass balance are needed. Plasma enhanced reversed reactions should be minimized by keeping conversion low and far from thermodynamic equilibrium, preventing underestimation of the rate of forward reaction. In contrast, plasma-catalytic studies often aim at conversions surpassing thermodynamic equilibrium, not obtaining any information on kinetics. Calculation of catalyst activity per active sites (turn-over-frequency) requires also appropriate characterization to determine the number of active sites. The relationship between kinetics and thermodynamics for plasma-catalysis is discussed using endothermic decomposition of CO2 and exothermic synthesis of ammonia from N2 and H2 as examples. Assuming Langmuir-Hinshelwood and Eley-Rideal mechanisms, the effect of excitation of reactant molecules on activation barriers and surface coverages are discussed, influencing reaction rates. The consequences of reversed reactions are considered. Plasma-catalysis with catalysts applied for thermal catalysis at much higher temperature should be avoided, as adsorbed species are bonded too strongly resulting in low rates.
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Affiliation(s)
- Leon Lefferts
- Catalytic Processes & Materials, MESA+ Institute, Faculty of Science and Technology, University of Twente, Drienerlolaan 5, 7522 NB, Enschede, The Netherlands
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Malahlela HK, Belay ZA, Mphahlele RR, Sigge GO, Caleb OJ. Recent advances in activated water systems for the postharvest management of quality and safety of fresh fruits and vegetables. Compr Rev Food Sci Food Saf 2024; 23:e13317. [PMID: 38477217 DOI: 10.1111/1541-4337.13317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 01/28/2024] [Accepted: 02/18/2024] [Indexed: 03/14/2024]
Abstract
Over the last three decades, decontamination management of fresh fruits and vegetables (FFVs) in the packhouses and along the supply chains has been heavily dependent on chemical-based wash. This has resulted in the emergence of resistant foodborne pathogens and often the deposition of disinfectant byproducts on FFVs, rendering them unacceptable to consumers. The management of foodborne pathogens, microbial contaminants, and quality of FFVs are a major concern for the horticultural industries and public health. Activated water systems (AWS), such as electrolyzed water, plasma-activated water, and micro-nano bubbles, have gained significant attention from researchers over the last decade due to their nonthermal and nontoxic mode of action for microbial inactivation and preservation of FFVs quality. The aim of this review is to provide a comprehensive summary of recent progress on the application of AWS and their effects on quality attributes and microbial safety of FFVs. An overview of the different types of AWS and their properties is provided. Furthermore, the review highlights the chemistry behind generation of reactive species and the impact of AWS on the quality attributes of FFVs and on the inactivation/reduction of spoilage and pathogenic microbes (in vivo or in vitro). The mechanisms of action of microorganism inactivation are discussed. Finally, this work highlights challenges and limitations for commercialization and safety and regulation issues of AWS. The synergistic prospect on combining AWS for maximum microorganism inactivation effectiveness is also considered. AWS offers a potential alternative as nonchemical interventions to maintain quality attributes, inactivate spoilage and pathogenic microorganisms, and extend the shelf-life for FFVs.
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Affiliation(s)
- Harold K Malahlela
- Department of Food Science, Faculty of AgriSciences, Stellenbosch University, Stellenbosch, South Africa
- AgriFood BioSystems and Technovation Research Group, Africa Institute for Postharvest Technology, Faculty of AgriSciences, Stellenbosch University, Stellenbosch, South Africa
| | - Zinash A Belay
- Post-Harvest and Agro-Processing Technologies (PHATs), Agricultural Research Council (ARC) Infruitec-Nietvoorbij, Stellenbosch, South Africa
| | | | - Gunnar O Sigge
- Department of Food Science, Faculty of AgriSciences, Stellenbosch University, Stellenbosch, South Africa
| | - Oluwafemi J Caleb
- Department of Food Science, Faculty of AgriSciences, Stellenbosch University, Stellenbosch, South Africa
- AgriFood BioSystems and Technovation Research Group, Africa Institute for Postharvest Technology, Faculty of AgriSciences, Stellenbosch University, Stellenbosch, South Africa
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Liang WP, Zhang XM, Bai PW, Zhang Z, Chen JH, Liu W, Sun ZH, Feng Y, Yang G, Tong HM, Xie T. Cascade N 2 Reduction Process with DBD Plasma Oxidation and Electrocatalytic Reduction for Continuous Ammonia Synthesis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:14558-14568. [PMID: 37728882 DOI: 10.1021/acs.est.3c05443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
Due to the extremely high bond energy of N≡N (∼941 kJ/mol), the traditional Haber-Bosch process of ammonia synthesis is known as an energy-intensive and high CO2-emission industry. In this paper, a cascade N2 reduction process with dielectric barrier discharge (DBD) plasma oxidation and electrocatalytic reduction as an alternative route is first proposed. N2 is oxidized to be reactive nitrogen species (RNS) by nonthermal plasma, which would then be absorbed by KOH solution and electroreduced to NH4+. It is found that the production of NOx is a function of discharge length, discharge power, and gas flow rate. Afterward, the cobalt catalyst is used in the process of electrocatalytic reduction of ammonia, which shows high selectivity (Faradic efficiency (FE) above 90%) and high yield of ammonia (45.45 mg/h). Finally, the cascade plasma oxidation and electrocatalytic reduction for ammonia synthesis is performed. Also, the performance of the reaction system is evaluated. It is worth mentioning that a stable and sustainable ammonia production efficiency of 16.21 mg/h is achieved, and 22.16% of NOx obtained by air activation is converted into NH4+. This work provides a demonstration for further industrial application of ammonia production with DBD plasma oxidation and electrocatalytic reduction techniques.
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Affiliation(s)
- Wen Peng Liang
- Institute of Industrial Catalysis, School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Xiao-Ming Zhang
- Xi'an Aerospace Yuan Dongli Engineering Co.,Ltd., Xi'an, Shaanxi 710100, P. R. China
| | - Pan-Wei Bai
- Institute of Industrial Catalysis, School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Zhenyu Zhang
- Institute of Industrial Catalysis, School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Jia-He Chen
- Institute of Industrial Catalysis, School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Wei Liu
- Institute of Industrial Catalysis, School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Zi-Han Sun
- Institute of High Voltage Physics and Engineering, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Yue Feng
- State Key Laboratory of Electrical Insulation and Power Equipment, Centre for Plasma Biomedicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Guidong Yang
- Institute of Industrial Catalysis, School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Hui-Min Tong
- Instrument Analysis Center of Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Tao Xie
- Institute of Industrial Catalysis, School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
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Hosseini H. Dielectric barrier discharge plasma catalysis as an alternative approach for the synthesis of ammonia: a review. RSC Adv 2023; 13:28211-28223. [PMID: 37753400 PMCID: PMC10519190 DOI: 10.1039/d3ra05580a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 09/14/2023] [Indexed: 09/28/2023] Open
Abstract
Numerous researchers have attempted to provide mild reactions and environmentally-friendly methods for NH3 synthesis. Research on non-thermal plasma-assisted ammonia synthesis, notably the atmospheric-pressure nonthermal plasma synthesis of ammonia over catalysts, has recently gained attention in the academic literature. Since non-thermal plasma technology circumvents the existing crises and harsh conditions of the Haber-Bosch process, it can be considered as a promising alternative for clean synthesis of ammonia. Non-thermal dielectric barrier discharge (DBD) plasma has been extensively employed in the synthesis of ammonia due to its particular advantages such as the simple construction of DBD reactors, atmospheric operation at ambient temperature, and low cost. The combination of this plasma and catalytic materials can remarkably affect ammonia formation, energy efficiency, and the generation of by-products. The present article reviews plasma-catalysis ammonia synthesis in a dielectric barrier discharge reactor and the parameters affecting this synthesis system. The proposed mechanisms of ammonia production by this plasma catalysis system are discussed as well.
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Affiliation(s)
- Hamideh Hosseini
- Chemistry and Chemical Engineering Research Center of Iran (CCERCI) PO Box 14335-186 Teheran Iran
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Navascués P, Garrido-García J, Cotrino J, González-Elipe AR, Gómez-Ramírez A. Incorporation of a Metal Catalyst for the Ammonia Synthesis in a Ferroelectric Packed-Bed Plasma Reactor: Does It Really Matter? ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2023; 11:3621-3632. [PMID: 36911874 PMCID: PMC9993574 DOI: 10.1021/acssuschemeng.2c05877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 02/02/2023] [Indexed: 06/18/2023]
Abstract
Plasma-catalysis has been proposed as a potential alternative for the synthesis of ammonia. Studies in this area focus on the reaction mechanisms and the apparent synergy existing between processes occurring in the plasma phase and on the surface of the catalytic material. In the present study, we approach this problem using a parallel-plate packed-bed reactor with the gap between the electrodes filled with pellets of lead zirconate titanate (PZT), with this ferroelectric material modified with a coating layer of alumina (i.e., Al2O3/PZT) and the same alumina layer incorporating ruthenium nanoparticles (i.e., Ru-Al2O3/PZT). At ambient temperature, the electrical behavior of the ferroelectric packed-bed reactor differed for these three types of barriers, with the plasma current reaching a maximum when using Ru-Al2O3/PZT pellets. A systematic analysis of the reaction yield and energy efficiency for the ammonia synthesis reaction, at ambient temperature and at 190 °C and various electrical operating conditions, has demonstrated that the yield and the energy efficiency for the ammonia synthesis do not significantly improve when including ruthenium particles, even at temperatures at which an incipient catalytic activity could be inferred. Besides disregarding a net plasma-catalysis effect, reaction results highlight the positive role of the ferroelectric PZT as moderator of the discharge, that of Ru particles as plasma hot points, and that of the Al2O3 coating as a plasma cooling dielectric layer.
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Affiliation(s)
- Paula Navascués
- Laboratory
of Nanotechnology on Surfaces and Plasma. Instituto de Ciencia de Materiales de Sevilla (CSIC-Universidad de
Sevilla), Avda. Américo Vespucio 49, E-41092 Seville, Spain
| | - Juan Garrido-García
- Laboratory
of Nanotechnology on Surfaces and Plasma. Instituto de Ciencia de Materiales de Sevilla (CSIC-Universidad de
Sevilla), Avda. Américo Vespucio 49, E-41092 Seville, Spain
| | - José Cotrino
- Laboratory
of Nanotechnology on Surfaces and Plasma. Instituto de Ciencia de Materiales de Sevilla (CSIC-Universidad de
Sevilla), Avda. Américo Vespucio 49, E-41092 Seville, Spain
- Departamento
de Física Atómica, Molecular y Nuclear, Universidad de Sevilla, Avda. Reina Mercedes, E-41012 Seville, Spain
| | - Agustín R. González-Elipe
- Laboratory
of Nanotechnology on Surfaces and Plasma. Instituto de Ciencia de Materiales de Sevilla (CSIC-Universidad de
Sevilla), Avda. Américo Vespucio 49, E-41092 Seville, Spain
| | - Ana Gómez-Ramírez
- Laboratory
of Nanotechnology on Surfaces and Plasma. Instituto de Ciencia de Materiales de Sevilla (CSIC-Universidad de
Sevilla), Avda. Américo Vespucio 49, E-41092 Seville, Spain
- Departamento
de Física Atómica, Molecular y Nuclear, Universidad de Sevilla, Avda. Reina Mercedes, E-41012 Seville, Spain
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