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Drosou C, Nikolaraki E, Georgakopoulou T, Fanourgiakis S, Zaspalis VT, Yentekakis IV. Methane Catalytic Combustion under Lean Conditions over Pristine and Ir-Loaded La 1-xSr xMnO 3 Perovskites: Efficiency, Hysteresis, and Time-on-Stream and Thermal Aging Stabilities. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2271. [PMID: 37570587 PMCID: PMC10420673 DOI: 10.3390/nano13152271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/02/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023]
Abstract
The increasing use of natural gas as an efficient, reliable, affordable, and cleaner energy source, compared with other fossil fuels, has brought the catalytic CH4 complete oxidation reaction into the spotlight as a simple and economic way to control the amount of unconverted methane escaping into the atmosphere. CH4 emissions are a major contributor to the 'greenhouse effect', and therefore, they need to be effectively reduced. Catalytic CH4 oxidation is a promising method that can be used for this purpose. Detailed studies of the activity, oxidative thermal aging, and the time-on-stream (TOS) stability of pristine La1-xSrxMnO3 perovskites (LSXM; X = % substitution of La with Sr = 0, 30, 50 and 70%) and iridium-loaded Ir/La1-xSrxMnO3 (Ir/LSXM) perovskite catalysts were conducted in a temperature range of 400-970 °C to achieve complete methane oxidation under excess oxygen (lean) conditions. The effect of X on the properties of the perovskites, and thus, their catalytic performance during heating/cooling cycles, was studied using samples that were subjected to various pretreatment conditions in order to gain an in-depth understanding of the structure-activity/stability correlations. Large (up to ca. 300 °C in terms of T50) inverted volcano-type differences in catalytic activity were found as a function of X, with the most active catalysts being those where X = 0%, and the least active were those where X = 50%. Inverse hysteresis phenomena (steady-state rate multiplicities) were revealed in heating/cooling cycles under reaction conditions, the occurrence of which was found to depend strongly on the employed catalyst pre-treatment (pre-reduction or pre-oxidation), while their shape and the loop amplitude were found to depend on X and the presence of Ir. All findings were consistently interpreted, which involved a two-term mechanistic model that utilized the synergy of Eley-Rideal and Mars-van Krevelen kinetics.
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Affiliation(s)
- Catherine Drosou
- Laboratory of Physical Chemistry and Chemical Processes, School of Chemical and Environmental Engineering, Technical University of Crete, 731 00 Chania, Crete, Greece; (E.N.); (T.G.); (S.F.)
| | - Ersi Nikolaraki
- Laboratory of Physical Chemistry and Chemical Processes, School of Chemical and Environmental Engineering, Technical University of Crete, 731 00 Chania, Crete, Greece; (E.N.); (T.G.); (S.F.)
| | - Theodora Georgakopoulou
- Laboratory of Physical Chemistry and Chemical Processes, School of Chemical and Environmental Engineering, Technical University of Crete, 731 00 Chania, Crete, Greece; (E.N.); (T.G.); (S.F.)
| | - Sotiris Fanourgiakis
- Laboratory of Physical Chemistry and Chemical Processes, School of Chemical and Environmental Engineering, Technical University of Crete, 731 00 Chania, Crete, Greece; (E.N.); (T.G.); (S.F.)
| | - Vassilios T. Zaspalis
- Department of Chemical Engineering, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece;
- Chemical Process and Energy Resources Institute, Center for Research and Technology Hellas (CPERI/CERTH), 570 01 Thermi, Thessaloniki, Greece
| | - Ioannis V. Yentekakis
- Laboratory of Physical Chemistry and Chemical Processes, School of Chemical and Environmental Engineering, Technical University of Crete, 731 00 Chania, Crete, Greece; (E.N.); (T.G.); (S.F.)
- Institute of GeoEnergy, Foundation for Research and Technology-Hellas (FORTH/IG), 731 00 Chania, Greece
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Drosou C, Nikolaraki E, Nikolaou V, Koilia E, Artemakis G, Stratakis A, Evdou A, Charisiou ND, Goula MA, Zaspalis V, Yentekakis IV. Activity and Thermal Aging Stability of La 1-xSr xMnO 3 (x = 0.0, 0.3, 0.5, 0.7) and Ir/La 1-xSr xMnO 3 Catalysts for CO Oxidation with Excess O 2. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:663. [PMID: 36839034 PMCID: PMC9964921 DOI: 10.3390/nano13040663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/05/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
The catalytic oxidation of CO is probably the most investigated reaction in the literature, for decades, because of its extended environmental and fundamental importance. In this paper, the oxidation of CO on La1-xSrxMnO3 perovskites (LSMx), either unloaded or loaded with dispersed Ir nanoparticles (Ir/LSMx), was studied in the temperature range 100-450 °C under excess O2 conditions (1% CO + 5% O2). The perovskites, of the type La1-xSrxMnO3 (x = 0.0, 0.3, 0.5 and 0.7), were prepared by the coprecipitation method. The physicochemical and structural properties of both the LSMx and the homologous Ir/LSMx catalysts were evaluated by various techniques (XRD, N2 sorption-desorption by BET-BJH, H2-TPR and H2-Chem), in order to better understand the structure-activity-stability correlations. The effect of preoxidation/prereduction/aging of the catalysts on their activity and stability was also investigated. Results revealed that both LSMx and Ir/LSMx are effective for CO oxidation, with the latter being superior to the former. In both series of materials, increasing the substitution of La by Sr in the composition of the perovskite resulted to a gradual suppression of their CO oxidation activity when these were prereduced; the opposite was true for preoxidized samples. Inverse hysteresis phenomena in activity were observed during heating/cooling cycles on the prereduced Ir/LSMx catalysts with the loop amplitude narrowing with increasing Sr-content in LSMx. Oxidative thermal sintering experiments at high temperatures revealed excellent antisintering behavior of Ir nanoparticles supported on LSMx, resulting from perovskite's favorable antisintering properties of high oxygen storage capacity and surface oxygen vacancies.
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Affiliation(s)
- Catherine Drosou
- Laboratory of Physical Chemistry & Chemical Processes, School of Chemical and Environmental Engineering, Technical University of Crete, 73100 Chania, Crete, Greece
| | - Ersi Nikolaraki
- Laboratory of Physical Chemistry & Chemical Processes, School of Chemical and Environmental Engineering, Technical University of Crete, 73100 Chania, Crete, Greece
| | - Vasilios Nikolaou
- Laboratory of Physical Chemistry & Chemical Processes, School of Chemical and Environmental Engineering, Technical University of Crete, 73100 Chania, Crete, Greece
| | - Evangelia Koilia
- Laboratory of Physical Chemistry & Chemical Processes, School of Chemical and Environmental Engineering, Technical University of Crete, 73100 Chania, Crete, Greece
| | - Georgios Artemakis
- Laboratory of Physical Chemistry & Chemical Processes, School of Chemical and Environmental Engineering, Technical University of Crete, 73100 Chania, Crete, Greece
| | - Antonios Stratakis
- School of Mineral Resources Engineering, Technical University of Crete, 73100 Chania, Crete, Greece
| | - Antigoni Evdou
- Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
- Chemical Process & Energy Resources Institute/Center for Research & Technology Hellas (CPERI/CERTH), 6th km Harilaou-Thermis, Thermi, 57001 Thessaloniki, Greece
| | - Nikolaos D. Charisiou
- Department of Chemical Engineering, University of Western Macedonia, 50100 Koila, Kozani, Greece
| | - Maria A. Goula
- Department of Chemical Engineering, University of Western Macedonia, 50100 Koila, Kozani, Greece
| | - Vasilios Zaspalis
- Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
- Chemical Process & Energy Resources Institute/Center for Research & Technology Hellas (CPERI/CERTH), 6th km Harilaou-Thermis, Thermi, 57001 Thessaloniki, Greece
| | - Ioannis V. Yentekakis
- Laboratory of Physical Chemistry & Chemical Processes, School of Chemical and Environmental Engineering, Technical University of Crete, 73100 Chania, Crete, Greece
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Gao X, Cai P, Wang Z, Lv X, Kawi S. Surface Acidity/Basicity and Oxygen Defects of Metal Oxide: Impacts on Catalytic Performances of CO2 Reforming and Hydrogenation Reactions. Top Catal 2022. [DOI: 10.1007/s11244-022-01708-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Baharudin L, Rahmat N, Othman NH, Shah N, Syed-Hassan SSA. Formation, control, and elimination of carbon on Ni-based catalyst during CO2 and CH4 conversion via dry reforming process: A review. J CO2 UTIL 2022. [DOI: 10.1016/j.jcou.2022.102050] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Yentekakis IV, Georgiadis AG, Drosou C, Charisiou ND, Goula MA. Selective Catalytic Reduction of NO x over Perovskite-Based Catalysts Using C xH y(O z), H 2 and CO as Reducing Agents-A Review of the Latest Developments. NANOMATERIALS 2022; 12:nano12071042. [PMID: 35407160 PMCID: PMC9000253 DOI: 10.3390/nano12071042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/16/2022] [Accepted: 03/18/2022] [Indexed: 12/04/2022]
Abstract
Selective catalytic reduction (SCR) is probably the most widespread process for limiting NOx emissions under lean conditions (O2 excess) and, in addition to the currently used NH3 or urea as a reducing agent, many other alternative reductants could be more promising, such as CxHy/CxHyOz, H2 and CO. Different catalysts have been used thus far for NOx abatement from mobile (automotive) and stationary (fossil fuel combustion plants) sources, however, perovskites demand considerable attention, partly due to their versatility to combine and incorporate various chemical elements in their lattice that favor deNOx catalysis. In this work, the CxHy/CxHyOz−, H2−, and CO-SCR of NOx on perovskite-based catalysts is reviewed, with particular emphasis on the role of the reducing agent nature and perovskite composition. An effort has also been made to further discuss the correlation between the physicochemical properties of the perovskite-based catalysts and their deNOx activity. Proposed kinetic models are presented as well, that delve deeper into deNOx mechanisms over perovskite-based catalysts and potentially pave the way for further improving their deNOx efficiency.
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Affiliation(s)
- Ioannis V. Yentekakis
- Laboratory of Physical Chemistry & Chemical Processes, School of Chemical & Environmental Engineering, Technical University of Crete, 73100 Chania, Greece;
- Foundation for Research and Technology—Hellas/Institute of Geoenergy (FORTH/IG), Technical University of Crete, Building M1, University Campus, 73100 Chania, Greece
- Correspondence: (I.V.Y.); (M.A.G.); Tel.: +30-28210-37752 (I.V.Y.); +30-24610-68296 (M.A.G.)
| | - Amvrosios G. Georgiadis
- Laboratory of Alternative Fuels and Environmental Catalysis (LAFEC), Department of Chemical Engineering, University of Western Macedonia, Koila, 50100 Kozani, Greece; (A.G.G.); (N.D.C.)
| | - Catherine Drosou
- Laboratory of Physical Chemistry & Chemical Processes, School of Chemical & Environmental Engineering, Technical University of Crete, 73100 Chania, Greece;
| | - Nikolaos D. Charisiou
- Laboratory of Alternative Fuels and Environmental Catalysis (LAFEC), Department of Chemical Engineering, University of Western Macedonia, Koila, 50100 Kozani, Greece; (A.G.G.); (N.D.C.)
| | - Maria A. Goula
- Laboratory of Alternative Fuels and Environmental Catalysis (LAFEC), Department of Chemical Engineering, University of Western Macedonia, Koila, 50100 Kozani, Greece; (A.G.G.); (N.D.C.)
- Correspondence: (I.V.Y.); (M.A.G.); Tel.: +30-28210-37752 (I.V.Y.); +30-24610-68296 (M.A.G.)
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Yentekakis IV. The 10th Anniversary of Nanomaterials-Recent Advances in Environmental Nanoscience and Nanotechnology. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:915. [PMID: 35335728 PMCID: PMC8951245 DOI: 10.3390/nano12060915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 03/02/2022] [Indexed: 01/27/2023]
Abstract
As a result of the rapid growth of nanoscience and nanotechnology, including advanced methods of fabrication and characterization of nanostructured materials, great progress has been made in many fields of science, not least in environmental catalysis, energy production and sustainability [...].
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Affiliation(s)
- Ioannis V. Yentekakis
- Laboratory of Physical Chemistry & Chemical Processes, School of Chemical and Environmental Engineering, Technical University of Crete (TUC), 73100 Chania, Crete, Greece; ; Tel.: +30-28210-37752
- Foundation for Research and Technology—Hellas/Institute of Geoenergy (FORTH/IG), Technical University of Crete, Building M1, University Campus, Acrotiri, 73100 Chania, Crete, Greece
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