An official website of the United States government
Thermochemical splitting of carbon dioxide to carbon-containing fuels or value-added chemicals is a promising method to reduce greenhouse effects. In this study, we propose a novel process for synchronous promotion of chemical looping-based CO 2 splitting with biomass cascade utilization. The superiority of the process is reflected in (1) a biomass fast pyrolysis process is carried out for syngas, phenolic-rich bio-oil, and biochar co-production with oxygen carrier reduction; (2) the reduced oxygen carrier and the biomass-derived biochar were both applied for CO 2 splitting during the oxygen carrier oxidation stage with carbon monoxide production as well as oxygen carrier re-oxidation; (3) the redox looping of the oxygen carrier was found to synchronously promote the comprehensive utilization of biomass and CO 2 splitting to CO. Various characterizations e.g. HRTEM- and SEM-EDX mapping, H 2 -TPR, CO 2 -TPO, XRD, XPS, N 2 nitrogen adsorption and desorption isotherm tests, Mössbauer, etc. were employed to elucidate the aerogels' microstructures, phase compositions, redox activity, and cyclic stability. Results indicate that the Ca 2 Fe 2 O 5 aerogel is a promising initiator of the proposed chemical looping process from the perspectives of biomass utilization efficiency, redox activity, and cyclic durability.
more »
« less
CO2-Utilization Facilitated by Solid Reaction Mediums—A Review
Abstract This short review examines solid reaction mediums—specifically oxygen, CO2, and carbon carriers—within the framework of Chemical Looping (CL) to illuminate various CO2utilization pathways. The thermodynamic consideration for carrier selection is first discussed. This is followed by a summary of the key carrier types investigated to date, with an emphasis on elucidating the roles of compositional, structural, and surface properties of the various carriers toward their reactive performances. Besides assessing the performances of various oxygen carriers, their long-term performance, potential deactivation mechanism in the presence of CO2,and strategies for their reactivation are also discussed in the context of chemical looping dry reforming of methane (CLDRM). While relatively underexplored, the current status of development, advantages, and potential limitations of CO2carriers in sorbent looping dry reforming of methane (SLDRM) and carbon carriers in chemical looping methane cracking (CLMC) are also reviewed and discussed. Emerging topics such as combined carriers are also covered along with a perspective for future research directions. Overall, this review aims to offer insights into the sustainable use of CO2through chemical looping, emphasizing the potential of solid reaction mediums across different carriers and the challenges associated with these solid reaction mediums.
more »
« less
- Award ID(s):
- 1923468
- PAR ID:
- 10578647
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Korean Journal of Chemical Engineering
- ISSN:
- 0256-1115
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Over the past two decades, chemical looping combustion (CLC) has been extensively investigated as a promising means to produce electric power while generating a concentrated carbon dioxide stream for sequestration. We note that the chemical looping strategy can be extended well outside of combustion-based carbon capture. In fact, application of the chemical looping strategy in areas beyond combustion can result in somewhat unexpected energy and carbon dioxide savings without producing a concentrated CO2 stream at all. Furthermore, it allows the looping-based technologies to tap into applications such as chemical production – a $4 trillion per year industrial sector with high energy and carbon intensities. The key resides in the design of effective oxygen carriers, also known as redox catalysts in the context of selective chemical conversion through chemical looping catalysis (CLCa). This contribution focuses on the design and applications of mixed oxides as multi-function reaction media in CLCa. Since typical mixed oxide oxygen carriers tend to be nonselective for hydrocarbon conversion, the first part of this article presents generalized design principles for surface modification of mixed oxides to improve their selectivity and catalytic activity. Applications of these redox catalysts in chemical looping – oxidative dehydrogenation (CL-ODH) of a variety of light alkanes and alkyl-benzenes are presented. This is followed with a discussion of computation assisted mixed oxide design based upon thermodynamic criteria. Finally, a few new directions for the chemical looping technologies are introduced.more » « less
-
Dielectric barrier discharge (DBD) plasma is a promising technology for catalysis due to its low‐temperature operation, cost‐effectiveness, and silent operation. This review comprehensively analyzes the design and operational parameters of DBD plasma reactors for three key catalytic applications: CH4conversion, CO2splitting, and dry reforming of methane (DRM). While catalyst selection is crucial for achieving desired product selectivity, reactor design and reaction parameters such as discharge power, electrode gap, reactor length, frequency, dielectric material thickness, and feed gas flow rate, significantly influence discharge characteristics and reaction mechanisms. This review also explores the influence of less prominent factors, such as electrode shape and applied voltage waveforms. Additionally, this review addresses the challenges of DBD plasma catalysis, including heat loss, temperature effects on discharge characteristics, and strategies for enhancing overall efficiency.more » « less
-
null (Ed.)Chemical Looping Reaction is a key strategy to achieve both emission reduction and carbon utilization while producing various value-added chemicals, through redox reactions. Here we study the effect of nanoshape ceria supported Ru catalysts for plasma assisted Chemical Looping Reforming reduction step coupled with water splitting oxidation step reactions in the temperature range 150 ⁰C to 400 ⁰C at 1 atm pressure. The oxygen carrier/catalyst combination materials used are Ru/CeO2 nanorods (NR), Ru/CeO2 nanocubes (NC), Ru/SiO2 nanospheres (NS), and Ni-based perovskite mixed with CeO2. NRs and NCs showed the best catalytic performance followed by Ni-based perovskite and NS. Differences in the selectivity and reactivity for the NRs and NCs were noticed. The NCs showed slightly higher selectivity towards H2 formation during reduction step and lesser carbon deposition. From the analysis of data and literature, it is proposed that the spillover of species such as H adatoms and CHx radicals after activation at Ru sites into the CeO2 supports and lattice O mobility may be slightly faster in the case of NCs. During the oxidation step, the NR and NC materials showed increased H2 production by a factor of more than 4 when compared to Ni based perovskite material.more » « less
-
Cerium oxide (CeO2) photo/electrocatalysts for energy storage and environmental applications have attracted considerable interest because of stable crystal structure, low toxicity/cost, superior chemical stability, stable redox (Ce3+/Ce4+) pairs, abundant oxygen defects, and capablility for intense interaction with other materials. However, the wide bandgap and poor conductivity lower the CeO2photo/electrocatalytic and energy storage performances. To overcome these limitations, various modification strategies (tuning morphology, doping or loading of metal nanoparticles, and heterostructures) have been applied for the improvement of photocatalytic (removal of organic contaminants from water/wastewater and H2production and CO2reduction reactions) efficiency, electrocatalytic (hydrogen/oxygen evolution reactions and CO2reduction reactions), and energy storage performances (supercapacitor) of CeO2‐based materials. Herein, the recent progress of CeO2‐based materials for electro(photo)catalysis and energy storage applications has been discussed. The challenges and possible direction of CeO2‐based materials for electro(photo)catalysis and energy storage applications have been emphasized. Furthermore, this comprehensive review is expected to advance the design of CeO2‐based materials and their applications in electro(photo)catalysis and energy.more » « less
