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Wei L, Pan Z, Shi X, Esan OC, Li G, Qi H, Wu Q, An L. Solar-driven thermochemical conversion of H 2O and CO 2 into sustainable fuels. iScience 2023; 26:108127. [PMID: 37876816 PMCID: PMC10590985 DOI: 10.1016/j.isci.2023.108127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023] Open
Abstract
Solar-driven thermochemical conversion of H2O and CO2 into sustainable fuels, based on redox cycle, provides a promising path for alternative energy, as it employs the solar energy as high-temperature heat supply and adopts H2O and CO2 as initial feedstock. This review describes the sustainable fuels production system, including a series of physical and chemical processes for converting solar energy into chemical energy in the form of sustainable fuels. Detailed working principles, redox materials, and key devices are reviewed and discussed to provide systematic and in-depth understanding of thermochemical fuels production with the aid of concentrated solar power technology. In addition, limiting factors affecting the solar-to-fuel efficiency are analyzed; meanwhile, the improvement technologies (heat recovery concepts and designs) are summarized. This study therefore sets a pathway for future research works based on the current status and demand for further development of such technologies on a commercial scale.
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Affiliation(s)
- Linyang Wei
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
- School of Metallurgy, Northeastern University, Shenyang 110819, China
| | - Zhefei Pan
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Xingyi Shi
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Oladapo Christopher Esan
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Guojun Li
- School of Metallurgy, Northeastern University, Shenyang 110819, China
| | - Hong Qi
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
| | - Qixing Wu
- Shenzhen Key Laboratory of New Lithium-ion Batteries and Mesoporous Materials, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Liang An
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
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2
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He M. Kinetics and Performance Study of Continuous Isothermal CeO2-Based Thermochemical Cycling for CO Production. RUSS J APPL CHEM+ 2022. [DOI: 10.1134/s1070427222090166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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3
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Nishimura T, Kodama T, Genta S, Ishii T. Transition metals doped effects for the crystal stabilization of the cerium oxides with the first principle calculation. Sci Rep 2022; 12:10103. [PMID: 35710587 PMCID: PMC9203553 DOI: 10.1038/s41598-022-14180-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 06/02/2022] [Indexed: 11/09/2022] Open
Abstract
In recent years, hydrogen energy has been attracting attention, and the hydrogen gas production using solar thermal energy has been conducted. The studies of Kodama et al. were reported that the cyclic reaction can efficiently produce the hydrogen gas through a two-step thermal redox reaction with the cerium oxide. The transition metal doping into the cerium oxide improved the reaction efficiency. We considered the doping effect on the thermal two-step redox reaction. As a result of the calculation by the DV-Xα method, it was clarified that the doped cerium oxide becomes a strong bond, the large BOP value without changing the ceria crystal structure in the two-step thermal redox reaction. The theoretical calculation results corresponded to the reaction efficiency improvement of the thermal reaction in experimental results.
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Affiliation(s)
- Takaki Nishimura
- Department of Advanced Materials Science, Graduate School of Engineering, Kagawa University, 2217-20 Hayashi-cho, Takamatsu, Kagawa, 761-0396, Japan
| | - Tatsuya Kodama
- Department of Engineering, Niigata University, 8050 Igarashi 2no-cyo, Nishi-ku, Niigata, 950-2181, Japan
| | - Sakane Genta
- Department of Chemistry, Faculty of Science, Okayama University of Science, 1-1 Ridaicho, Kita-ku, Okayama, 700-0005, Japan
| | - Tomohiko Ishii
- Department of Advanced Materials Science, Graduate School of Engineering, Kagawa University, 2217-20 Hayashi-cho, Takamatsu, Kagawa, 761-0396, Japan.
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4
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A Comprehensive Review on Two-Step Thermochemical Water Splitting for Hydrogen Production in a Redox Cycle. ENERGIES 2022. [DOI: 10.3390/en15093044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The interest in and need for carbon-free fuels that do not rely on fossil fuels are constantly growing from both environmental and energetic perspectives. Green hydrogen production is at the core of the transition away from conventional fuels. Along with popularly investigated pathways for hydrogen production, thermochemical water splitting using redox materials is an interesting option for utilizing thermal energy, as this approach makes use of temperature looping over the material to produce hydrogen from water. Herein, two-step thermochemical water splitting processes are discussed and the key aspects are analyzed using the most relevant information present in the literature. Redox materials and their compositions, which have been proven to be efficient for this reaction, are reported. Attention is focused on non-volatile redox oxides, as the quenching step required for volatile redox materials is unnecessary. Reactors that could be used to conduct the reduction and oxidation reaction are discussed. The most promising materials are compared to each other using a multi-criteria analysis, providing a direction for future research. As evident, ferrite supported on yttrium-stabilized zirconia, ceria doped with zirconia or samarium and ferrite doped with nickel as the core and an yttrium (III) oxide shell are promising choices. Isothermal cycling and lowering of the reduction temperature are outlined as future directions towards increasing hydrogen yields and improving the cyclability.
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5
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Abstract
Aviation and shipping currently contribute approximately 8% of total anthropogenic CO2 emissions, with growth in tourism and global trade projected to increase this contribution further1-3. Carbon-neutral transportation is feasible with electric motors powered by rechargeable batteries, but is challenging, if not impossible, for long-haul commercial travel, particularly air travel4. A promising solution are drop-in fuels (synthetic alternatives for petroleum-derived liquid hydrocarbon fuels such as kerosene, gasoline or diesel) made from H2O and CO2 by solar-driven processes5-7. Among the many possible approaches, the thermochemical path using concentrated solar radiation as the source of high-temperature process heat offers potentially high production rates and efficiencies8, and can deliver truly carbon-neutral fuels if the required CO2 is obtained directly from atmospheric air9. If H2O is also extracted from air10, feedstock sourcing and fuel production can be colocated in desert regions with high solar irradiation and limited access to water resources. While individual steps of such a scheme have been implemented, here we demonstrate the operation of the entire thermochemical solar fuel production chain, from H2O and CO2 captured directly from ambient air to the synthesis of drop-in transportation fuels (for example, methanol and kerosene), with a modular 5 kWthermal pilot-scale solar system operated under field conditions. We further identify the research and development efforts and discuss the economic viability and policies required to bring these solar fuels to market.
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6
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Portarapillo M, Russo D, Landi G, Luciani G, Di Benedetto A. K-doped CeO 2-ZrO 2 for CO 2 thermochemical catalytic splitting. RSC Adv 2021; 11:39420-39427. [PMID: 35492484 PMCID: PMC9044484 DOI: 10.1039/d1ra08315e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 12/01/2021] [Indexed: 11/21/2022] Open
Abstract
Green syngas production is a sustainable energy-development goal. Thermochemical H2O/CO2 splitting is a very promising sustainable technology allowing the production of H2 and CO with only oxygen as the by-product. CeO2-ZrO2 systems are well known thermochemical splitting catalysts, since they combine stability at high temperature with rapid kinetics and redox cyclability. However, redox performances of these materials must be improved to allow their use in large scale plants. K-doped systems show good redox properties and repeatable performances. In this work, we studied the effect of potassium content on the performances of ceria-zirconia for CO2 splitting. A kinetic model was developed to get insight into the nature of the catalytic sites. Fitting results confirmed the hypothesis about the existence of two types of redox sites in the investigated catalytic systems and their role at different K contents. Moreover, the model was used to predict the influence of key parameters, such as the process conditions.
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Affiliation(s)
- Maria Portarapillo
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II Naples 80125 Italy
| | - Danilo Russo
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II Naples 80125 Italy
| | - Gianluca Landi
- Istituto di Scienze e Tecnologie per l'Energia e la Mobilità Sostenibili STEMS-CNR Naples 80125 Italy
| | - Giuseppina Luciani
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II Naples 80125 Italy
| | - Almerinda Di Benedetto
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II Naples 80125 Italy
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7
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Coker EN, Ambrosini A, Miller JE. Compositional and operational impacts on the thermochemical reduction of CO 2 to CO by iron oxide/yttria-stabilized zirconia. RSC Adv 2021; 11:1493-1502. [PMID: 35424107 PMCID: PMC8693632 DOI: 10.1039/d0ra08589h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/15/2020] [Indexed: 11/21/2022] Open
Abstract
Ferrites have potential for use as active materials in solar-thermochemical cycles because of their versatile redox chemistry. Such cycles utilize solar-thermal energy for the production of hydrogen from water and carbon monoxide from carbon dioxide. Although ferrites offer the potential for deep levels of reduction (e.g., stoichiometric conversion of magnetite to wüstite) and correspondingly large per-cycle product yields, in practice reactions are limited to surface regions made smaller by rapid sintering and agglomeration. Combining ferrites with zirconia or yttria-stabilized zirconia (YSZ) greatly improves the cyclability of the ferrites and enables a move away from powder to monolithic systems. We have studied the behavior of iron oxides composited with YSZ using thermogravimetric analysis under operando conditions. Samples in which the iron was fully dissolved within the YSZ matrix showed greater overall extent of thermochemical redox and higher rate of reaction than samples with equal iron loading but in which the iron was only partially dissolved, with the rest existing as agglomerates of iron oxide within the ceramic matrix. Varying the yttria content of the YSZ revealed a maximum thermochemical capacity (yield per cycle) for 6 mol% Y2O3 in YSZ. The first thermochemical redox cycle performed for each sample resulted in a net mass loss that was proportional to the iron oxide loading in the material and was stoichiometrically consistent with complete reduction of Fe2O3 to Fe3O4 and further partial reduction of the Fe3O4 to FeO. Mass gains upon reaction with CO2 were consistent with re-oxidation of the FeO fraction back to Fe3O4. The Fe dissolved in the YSZ matrix, however, is capable of cycling stoichiometrically between Fe3+ and Fe2+. Varying the re-oxidation temperature between 1000 and 1200 °C highlighted the trade-off between re-oxidation rate and equilibrium limitations.
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Affiliation(s)
- Eric N Coker
- Sandia National Laboratories P.O. Box 5800 Albuquerque NM 87185-1411 USA
| | - Andrea Ambrosini
- Sandia National Laboratories P.O. Box 5800 Albuquerque NM 87185-1411 USA
| | - James E Miller
- LightWorks®, Arizona State University Tempe AZ 85281 USA
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8
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Ali S, Humayun M, Pi W, Yuan Y, Wang M, Khan A, Yue P, Shu L, Zheng Z, Fu Q, Luo W. Fabrication of BiFeO 3-g-C 3N 4-WO 3 Z-scheme heterojunction as highly efficient visible-light photocatalyst for water reduction and 2,4-dichlorophenol degradation: Insight mechanism. JOURNAL OF HAZARDOUS MATERIALS 2020; 397:122708. [PMID: 32361672 DOI: 10.1016/j.jhazmat.2020.122708] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 03/31/2020] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
In this work, a Z-scheme BiFeO3-g-C3N4-WO3 (BFO-CN-WO) photocatalyst has been synthesized via a wet chemical method and utilized in photocatalysis for hydrogen generation and 2,4-dichlorophenol (2,4-DCP) degradation under visible light irradiation. The resultant photocatalyst showed 90 μmol·h-1 g-1 H2 evolution activity and 63% 2,4-DCP degradation performance, which is 12 and 4.2 times higher than the pristine g-C3N4 respectively. The fascinating photocatalytic performance is attributed to the strong interfacial contact between g-C3N4 and the coupled BiFeO3 and WO3 component, which greatly improved the visible light absorption and charge carriers' separation. The designed Z-scheme heterojunction is a successful strategy for enhancing the separation efficiency of photo-induced charge carriers at the interface while retaining outstanding redox ability. During 2,4-DCP degradation, LC/MS technique was used to detect the reaction intermediates. According to the LC/MS results, several new intermediates such as 2,3-dichloro-6-(2,4-dichlorophenoxy)phenol (m/z = 306), 2,4-dichlorophenyl hydrogen carbonate (m/z = 207), 2,4-dichlorobenzen-1,3-diol (m/z = 177) and phenyl hydrogen carbonate (m/z = 137) were detected. Based on these intermediates, 2,4-DCP degradation pathway is proposed. The fluorescence (FL) and electron paramagnetic resonance (EPR) results reveal that the •OH plays an important role in the 2,4-DCP degradation. The fabricated photocatalyst can be utilized in the field of photocatalysis for practical applications.
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Affiliation(s)
- Sher Ali
- Engineering Research Center for Functional Ceramics of the Ministry of Education, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Muhammad Humayun
- Engineering Research Center for Functional Ceramics of the Ministry of Education, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China; China-EU Institute for Clean and Renewable Energy, HuazhongUniversity of Science and Technology, Wuhan 430074, PR China
| | - Wenbo Pi
- Engineering Research Center for Functional Ceramics of the Ministry of Education, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Yang Yuan
- Engineering Research Center for Functional Ceramics of the Ministry of Education, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Mei Wang
- Engineering Research Center for Functional Ceramics of the Ministry of Education, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Abbas Khan
- Department of Chemistry, Abdul Wali Khan University Mardan, Mardan 23200, Khyber Pakhtunkhwa, Pakistan
| | - Pang Yue
- College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, PR China
| | - Lang Shu
- Engineering Research Center for Functional Ceramics of the Ministry of Education, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Zhiping Zheng
- Engineering Research Center for Functional Ceramics of the Ministry of Education, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Qiuyun Fu
- Engineering Research Center for Functional Ceramics of the Ministry of Education, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Wei Luo
- Engineering Research Center for Functional Ceramics of the Ministry of Education, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, PR China; China-EU Institute for Clean and Renewable Energy, HuazhongUniversity of Science and Technology, Wuhan 430074, PR China.
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9
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CO production from CO2 and H2 via the rWGS reaction by thermochemical redox cycling in interconnected fluidized beds. J CO2 UTIL 2020. [DOI: 10.1016/j.jcou.2020.101191] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Haribal VP, He F, Mishra A, Li F. Iron-Doped BaMnO 3 for Hybrid Water Splitting and Syngas Generation. CHEMSUSCHEM 2017; 10:3402-3408. [PMID: 28782914 DOI: 10.1002/cssc.201700699] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Indexed: 06/07/2023]
Abstract
A rationalized strategy to optimize transition-metal-oxide-based redox catalysts for water splitting and syngas generation through a hybrid solar-redox process is proposed and validated. Monometallic transition metal oxides do not possess desirable properties for water splitting; however, density functional theory calculations indicate that the redox properties of perovskite-structured BaMnx Fe1-x O3-δ can be varied by changing the B-site cation compositions. Specifically, BaMn0.5 Fe0.5 O3-δ is projected to be suitable for the hybrid solar-redox process. Experimental studies confirm such predictions, demonstrating 90 % steam-to-hydrogen conversion in water splitting and over 90 % syngas yield in the methane partial-oxidation step after repeated redox cycles. Compared to state-of-the-art solar-thermal water-splitting catalysts, the rationally designed redox catalyst reported is capable of splitting water at a significantly lower temperature and with ten-fold increase in steam-to-hydrogen conversion. Process simulations indicate the potential to operate the hybrid solar-redox process at a higher efficiency than state-of-the-art hydrogen and liquid-fuel production processes with 70 % lower CO2 emissions for hydrogen production.
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Affiliation(s)
- Vasudev Pralhad Haribal
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC, 27695-7905, USA
| | - Feng He
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC, 27695-7905, USA
| | - Amit Mishra
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC, 27695-7905, USA
| | - Fanxing Li
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC, 27695-7905, USA
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11
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Rothensteiner M, Jenni J, Emerich H, Bonk A, Vogt UF, van Bokhoven JA. In situ flow cell for combined X-ray absorption spectroscopy, X-ray diffraction, and mass spectrometry at high photon energies under solar thermochemical looping conditions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:083116. [PMID: 28863639 DOI: 10.1063/1.4994890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
An in situ/operando flow cell for transmission mode X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), and combined XAS/XRD measurements in a single experiment under the extreme conditions of two-step solar thermochemical looping for the dissociation of water and/or carbon dioxide was developed. The apparatus exposes materials to relevant conditions of both the auto-reduction and the oxidation sub-steps of the thermochemical cycle at ambient temperature up to 1773 K and enables determination of the composition of the effluent gases by online quadrupole mass spectrometry. The cell is based on a tube-in-tube design and is heated by means of a focusing infrared furnace. It was tested successfully for carbon dioxide splitting. In combined XAS/XRD experiments with an unfocused beam, XAS measurements were performed at the Ce K edge (40.4 keV) and XRD measurements at 64.8 keV and 55.9 keV. Furthermore, XRD measurements with a focused beam at 41.5 keV were carried out. Equimolar ceria-hafnia was auto-reduced in a flow of argon and chemically reduced in a flow of hydrogen/helium. Under reducing conditions, all cerium(iv) was converted to cerium(iii) and a cation-ordered pyrochlore-type structure was formed, which was not stable upon oxidation in a flow of carbon dioxide.
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Affiliation(s)
- Matthäus Rothensteiner
- Institute for Chemical and Bioengineering, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Joel Jenni
- Institute for Chemical and Bioengineering, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Hermann Emerich
- European Synchrotron Radiation Facility, 6 Rue Jules Horowitz BP 220, F-38043 Grenoble Cedex, France
| | - Alexander Bonk
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory of Materials for Energy Conversion, 8600 Dübendorf, Switzerland
| | - Ulrich F Vogt
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory of Materials for Energy Conversion, 8600 Dübendorf, Switzerland
| | - Jeroen A van Bokhoven
- Institute for Chemical and Bioengineering, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
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12
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Abstract
Solar photochemical means of splitting water (artificial photosynthesis) to generate hydrogen is emerging as a viable process. The solar thermochemical route also promises to be an attractive means of achieving this objective. In this paper we present different types of thermochemical cycles that one can use for the purpose. These include the low-temperature multistep process as well as the high-temperature two-step process. It is noteworthy that the multistep process based on the Mn(II)/Mn(III) oxide system can be carried out at 700 °C or 750 °C. The two-step process has been achieved at 1,300 °C/900 °C by using yttrium-based rare earth manganites. It seems possible to render this high-temperature process as an isothermal process. Thermodynamics and kinetics of H2O splitting are largely controlled by the inherent redox properties of the materials. Interestingly, under the conditions of H2O splitting in the high-temperature process CO2 can also be decomposed to CO, providing a feasible method for generating the industrially important syngas (CO+H2). Although carbonate formation can be addressed as a hurdle during CO2 splitting, the problem can be avoided by a suitable choice of experimental conditions. The choice of the solar reactor holds the key for the commercialization of thermochemical fuel production.
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13
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Wenzel M, Rihko-Struckmann L, Sundmacher K. Thermodynamic analysis and optimization of RWGS processes for solar syngas production from CO2. AIChE J 2016. [DOI: 10.1002/aic.15445] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Marcus Wenzel
- Max Planck Institute for Dynamics of Complex Technical Systems; Sandtorstr. 1 Magdeburg 39106 Germany
| | - Liisa Rihko-Struckmann
- Max Planck Institute for Dynamics of Complex Technical Systems; Sandtorstr. 1 Magdeburg 39106 Germany
| | - Kai Sundmacher
- Max Planck Institute for Dynamics of Complex Technical Systems; Sandtorstr. 1 Magdeburg 39106 Germany
- Otto-von-Guericke-University Magdeburg; Universitätsplatz 2 Magdeburg 39106 Germany
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14
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Takacs M, Scheffe JR, Steinfeld A. Oxygen nonstoichiometry and thermodynamic characterization of Zr doped ceria in the 1573-1773 K temperature range. Phys Chem Chem Phys 2015; 17:7813-22. [PMID: 25714616 PMCID: PMC4766580 DOI: 10.1039/c4cp04916k] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The thermodynamics and defect chemistry of Zr4+-doped ceria is investigated and discussed in regards to the efficiency of solar thermochemical redox cycles.
This work encompasses the thermodynamic characterization and critical evaluation of Zr4+ doped ceria, a promising redox material for the two-step solar thermochemical splitting of H2O and CO2 to H2 and CO. As a case study, we experimentally examine 5 mol% Zr4+ doped ceria and present oxygen nonstoichiometry measurements at elevated temperatures ranging from 1573 K to 1773 K and oxygen partial pressures ranging from 4.50 × 10–3 atm to 2.3 × 10–4 atm, yielding higher reduction extents compared to those of pure ceria under all conditions investigated, especially at the lower temperature range and at higher pO2. In contrast to pure ceria, a simple ideal solution model accounting for the formation of isolated oxygen vacancies and localized electrons accurately describes the defect chemistry. Thermodynamic properties are determined, namely: partial molar enthalpy, entropy, and Gibbs free energy. In general, partial molar enthalpy and entropy values of Zr4+ doped ceria are lower. The equilibrium hydrogen yields are subsequently extracted as a function of the redox conditions for dopant concentrations as high as 20%. Although reduction extents increase greatly with dopant concentration, the oxidation of Zr4+ doped ceria is thermodynamically less favorable compared to pure ceria. This leads to substantially larger temperature swings between reduction and oxidation steps, ultimately resulting in lower theoretical solar energy conversion efficiencies compared to ceria under most conditions. In effect, these results point to the importance of considering oxidation thermodynamics in addition to reduction when screening potential redox materials.
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Affiliation(s)
- M Takacs
- Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
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15
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16
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Rothensteiner M, Sala S, Bonk A, Vogt U, Emerich H, van Bokhoven JA. Ce K edge XAS of ceria-based redox materials under realistic conditions for the two-step solar thermochemical dissociation of water and/or CO2. Phys Chem Chem Phys 2015; 17:26988-96. [DOI: 10.1039/c5cp03179f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
X-ray absorption spectroscopy was used to characterise ceria-based materials under realistic conditions present in a reactor for solar thermochemical two-step water and carbon dioxide splitting.
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Affiliation(s)
- Matthäus Rothensteiner
- Paul Scherrer Institut
- 5232 Villigen PSI
- Switzerland
- Institute for Chemical and Bioengineering
- ETH Zürich
| | - Simone Sala
- Paul Scherrer Institut
- 5232 Villigen PSI
- Switzerland
| | | | | | | | - Jeroen A. van Bokhoven
- Paul Scherrer Institut
- 5232 Villigen PSI
- Switzerland
- Institute for Chemical and Bioengineering
- ETH Zürich
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17
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Navarrete A, Muñoz S, Sanz-Moral LM, Brandner JJ, Pfeifer P, Martín Á, Dittmeyer R, Cocero MJ. Novel windows for “solar commodities”: a device for CO2 reduction using plasmonic catalyst activation. Faraday Discuss 2015; 183:249-59. [DOI: 10.1039/c5fd00109a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel plasmonic reactor concept is proposed and tested to work as a visible energy harvesting device while allowing reactions to transform CO2 to be carried out. Particularly the reverse water gas shift (RWGS) reaction has been tested as a means to introduce renewable energy into the economy. The development of the new reactor concept involved the synthesis of a new composite capable of plasmonic activation with light, the development of an impregnation method to create a single catalyst reactor entity, and finally the assembly of a reaction system to test the reaction. The composite developed was based on a Cu/ZnO catalyst dispersed into transparent aerogels. This allows efficient light transmission and a high surface area for the catalyst. An effective yet simple impregnation method was developed that allowed introduction of the composites into glass microchannels. The activation of the reaction was made using LEDs that covered all the sides of the reactor allowing a high power delivery. The results of the reaction show a stable process capable of low temperature transformations.
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Affiliation(s)
- Alexander Navarrete
- University of Valladolid
- Department of Chemical Engineering and Environmental
- Technology
- High Pressure Processes Group
- 47005 Valladolid
| | - Sergio Muñoz
- University of Valladolid
- Department of Chemical Engineering and Environmental
- Technology
- High Pressure Processes Group
- 47005 Valladolid
| | - Luis M. Sanz-Moral
- University of Valladolid
- Department of Chemical Engineering and Environmental
- Technology
- High Pressure Processes Group
- 47005 Valladolid
| | - Juergen J. Brandner
- Institute for Micro Process Engineering
- Karlsruhe Institute for Technology
- Germany
| | - Peter Pfeifer
- Institute for Micro Process Engineering
- Karlsruhe Institute for Technology
- Germany
| | - Ángel Martín
- University of Valladolid
- Department of Chemical Engineering and Environmental
- Technology
- High Pressure Processes Group
- 47005 Valladolid
| | - Roland Dittmeyer
- Institute for Micro Process Engineering
- Karlsruhe Institute for Technology
- Germany
| | - María J. Cocero
- University of Valladolid
- Department of Chemical Engineering and Environmental
- Technology
- High Pressure Processes Group
- 47005 Valladolid
| |
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