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Dlamini N, Mukaya HE, Nkazi D. Carbon-based nanomaterials production from environmental pollutant byproducts: A Review. J CO2 UTIL 2022. [DOI: 10.1016/j.jcou.2022.101953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Sharma K, Park YK, Nadda AK, Banerjee P, Singh P, Raizada P, Banat F, Bharath G, Jeong SM, Lam SS. Emerging chemo-biocatalytic routes for valorization of major greenhouse gases (GHG) into industrial products: A comprehensive review. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2022.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Controlled Transition Metal Nucleated Growth of Carbon Nanotubes by Molten Electrolysis of CO2. Catalysts 2022. [DOI: 10.3390/catal12020137] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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 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).
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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 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.
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Key-Parameters in Chemical Stabilization of Soils with Multiwall Carbon Nanotubes. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11188754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Chemical stabilization is one of the most successful techniques that has been applied to improve the geomechanical behavior of soil. Several additives have been studied to be a sustainable alternative to traditional additives (Portland cement and lime) normally associated with high cost and carbon footprint. Nanomaterials are one of the most recent additives proposed. This work is focused on one type of nanomaterial, multiwall carbon nanotubes (MWCNTs) with unique characteristics, applied to chemical stabilization of soils and aiming to identify the key-parameters affecting the stabilization improvement. It was found that a surfactant should be added in order to oppose the natural tendency of MWCNTs to aggregate with the consequent loss of benefits. The surfactant choice is not so dependent on the charge of the surfactant but rather on the balance between the concentration and the hydrodynamic diameter/molecular weight due to their impact on the geomechanical compression behavior. As time evolves from 7 to 28 days, there is a decrease in the geomechanical benefits associated with the presence of MWCNTs explained by the development of the cementitious matrix. MWCNTs applied in a proper concentration and enriched with a specific surfactant type may be a short-time valid alternative to the partial replacement of traditional additives.
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Halilu A, Hayyan M, Aroua MK, Yusoff R, Hizaddin HF. Mechanistic insights into carbon dioxide utilization by superoxide ion generated electrochemically in ionic liquid electrolyte. Phys Chem Chem Phys 2021; 23:1114-1126. [PMID: 33346756 DOI: 10.1039/d0cp04903d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Understanding the reaction mechanism that controls the one-electron electrochemical reduction of oxygen is essential for sustainable use of the superoxide ion (O2˙-) during CO2 conversion. Here, stable generation of O2˙- in butyltrimethylammonium bis(trifluoromethylsulfonyl)imide [BMAmm+][TFSI-] ionic liquid (IL) was first detected at -0.823 V vs. Ag/AgCl using cyclic voltammetry (CV). The charge transfer coefficient associated with the process was ∼0.503. It was determined that [BMAmm+][TFSI-] is a task-specific IL with a large negative isovalue surface density accrued from the [BMAmm+] cation with negatively charged C(sp2) and C(sp3). Consequently, [BMAmm+][TFSI-] is less susceptible to the nucleophilic effect of O2˙- because only 8.4% O2˙- decay was recorded from 3 h long-term stability analysis. The CV analysis also detected that O2˙- mediated CO2 conversion in [BMAmm+][TFSI-] at -0.806 V vs. Ag/AgCl as seen by the disappearance of the oxidative faradaic current of O2˙-. Electrochemical impedance spectroscopy (EIS) detected the mechanism of O2˙- generation and CO2 conversion in [BMAmm+][TFSI-] for the first time. The EIS parameters in O2 saturated [BMAmm+][TFSI-] were different from those detected in O2/CO2 saturated [BMAmm+][TFSI-] or CO2 saturated [BMAmm+][TFSI-]. This was rationalized to be due to the formation of a [BMAmm+][TFSI-] film on the GC electrode, creating a 2.031 × 10-9 μF cm-2 double-layer capacitance (CDL). Therefore, during the O2˙- generation and CO2 utilization in [BMAmm+][TFSI-], the CDL increased to 5.897 μF cm-2 and 7.763 μF cm-2, respectively. The CO2 in [BMAmm+][TFSI-] was found to be highly unlikely to be electrochemically converted due to the high charge transfer resistance of 6.86 × 1018 kΩ. Subsequently, O2˙- directly mediated the CO2 conversion through a nucleophilic addition reaction pathway. These results offer new and sustainable opportunities for utilizing CO2 by reactive oxygen species in ionic liquid media.
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Affiliation(s)
- Ahmed Halilu
- Department of Chemical Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia. and University of Malaya Centre for Ionic Liquids (UMCiL), University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Maan Hayyan
- University of Malaya Centre for Ionic Liquids (UMCiL), University of Malaya, Kuala Lumpur 50603, Malaysia. and Chemical Engineering Program, Faculty of Engineering and Technology, Muscat University, P. O. Box 550, Muscat, P.C. 130, Oman
| | - Mohamed Kheireddine Aroua
- Centre for Carbon Dioxide Capture and Utilization (CCDCU), School of Engineering and Technology, Sunway University, Bandar Sunway, 47500 Petaling Jaya, Malaysia. and Department of Engineering, Lancaster University, Lancaster, LA1 4YW, UK
| | - Rozita Yusoff
- Department of Chemical Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia.
| | - Hanee F Hizaddin
- Department of Chemical Engineering, University of Malaya, Kuala Lumpur, 50603, Malaysia. and University of Malaya Centre for Ionic Liquids (UMCiL), University of Malaya, Kuala Lumpur 50603, Malaysia.
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One pot facile transformation of CO 2 to an unusual 3-D nano-scaffold morphology of carbon. Sci Rep 2020; 10:21518. [PMID: 33298989 PMCID: PMC7726567 DOI: 10.1038/s41598-020-78258-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 11/18/2020] [Indexed: 11/08/2022] Open
Abstract
An electrosynthesis is presented to transform CO2 into an unusual nano and micron dimensioned morphology of carbon, termed Carbon Nano-Scaffold (CNS) with wide a range of high surface area graphene potential usages including batteries, supercapacitors, compression devices, electromagnetic wave shielding and sensors. Current CNS value is over $323 per milligram. The morphology consists of a series of asymmetric 20 to 100 nm thick flat multilayer graphene platelets 2 to 20 µm long orthogonally oriented in a 3D neoplasticism-like geometry, and appears distinct from the honeycomb, foam, or balsa wood cell structures previously attributed to carbon scaffolds. The CNS synthesis splits CO2 by electrolysis in molten carbonate and has a carbon negative footprint. It is observed that transition metal nucleated, high yield growth of carbon nanotubes (CNTs) is inhibited in electrolytes containing over 50 wt% of sodium or 30 wt% of potassium carbonate, or at electrolysis temperatures less than 700 °C. Here, it is found that a lower temperature of synthesis, lower concentrations of lithium carbonate, and higher current density promotes CNS growth while suppressing CNT growth. Electrolyte conditions of 50 wt% sodium carbonate relative to lithium carbonate at an electrolysis temperature of 670 °C produced over 80% of the CNS desired product at 85% faradaic efficiency with a Muntz brass cathode and an Inconel anode.
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Calcium metaborate induced thin walled carbon nanotube syntheses from CO 2 by molten carbonate electrolysis. Sci Rep 2020; 10:15146. [PMID: 32934276 PMCID: PMC7493996 DOI: 10.1038/s41598-020-71644-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 08/17/2020] [Indexed: 11/18/2022] Open
Abstract
An electrosynthesis is presented to transform the greenhouse gas CO2 into an unusually thin walled, smaller diameter morphology of Carbon Nanotubes (CNTs). The transformation occurs at high yield and coulombic efficiency of the 4-electron CO2 reduction in a molten carbonate electrolyte. The electrosynthesis is driven by an unexpected synergy between calcium and metaborate. In a pure molten lithium carbonate electrolyte, thicker walled CNTs (100–160 nm diameter) are synthesized during a 4 h CO2 electrolysis at 0.1 A cm−2. At this low current density, CO2 without pre-concentration is directly absorbed by the air (direct air capture) to renew and sustain the carbonate electrolyte. The addition of 2 wt% Li2O to the electrolyte produces thinner, highly uniform (50–80 nm diameter) walled CNTs, consisting of ~ 75 concentric, cylindrical graphene walls. The product is produced at high yield (the cathode product consists of > 98% CNTs). It had previously been demonstrated that the addition of 5–10 wt% lithium metaborate to the lithium carbonate electrolyte boron dopes the CNTs increasing their electrical conductivity tenfold, and that the addition of calcium carbonate to a molten lithium carbonate supports the electrosynthesis of thinner walled CNTs, but at low yield (only ~ 15% of the product are CNTs). Here it is shown that the same electrolysis conditions, but with the addition of 7.7 wt% calcium metaborate to lithium carbonate, produces unusually thin walled CNTs uniform (22–42 nm diameter) CNTs consisting of ~ 25 concentric, cylindrical graphene walls at a high yield of > 90% CNTs.
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Magnetic carbon nanotubes: Carbide nucleated electrochemical growth of ferromagnetic CNTs from CO2. J CO2 UTIL 2020. [DOI: 10.1016/j.jcou.2020.101218] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Wang X, Liu X, Licht G, Wang B, Licht S. Exploration of alkali cation variation on the synthesis of carbon nanotubes by electrolysis of CO2 in molten carbonates. J CO2 UTIL 2019. [DOI: 10.1016/j.jcou.2019.07.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Toward electrochemical synthesis of cement-An electrolyzer-based process for decarbonating CaCO 3 while producing useful gas streams. Proc Natl Acad Sci U S A 2019; 117:12584-12591. [PMID: 31527245 DOI: 10.1073/pnas.1821673116] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cement production is currently the largest single industrial emitter of CO2, accounting for ∼8% (2.8 Gtons/y) of global CO2 emissions. Deep decarbonization of cement manufacturing will require remediation of both the CO2 emissions due to the decomposition of CaCO3 to CaO and that due to combustion of fossil fuels (primarily coal) in calcining (∼900 °C) and sintering (∼1,450 °C). Here, we demonstrate an electrochemical process that uses neutral water electrolysis to produce a pH gradient in which CaCO3 is decarbonated at low pH and Ca(OH)2 is precipitated at high pH, concurrently producing a high-purity O2/CO2 gas mixture (1:2 molar ratio at stoichiometric operation) at the anode and H2 at the cathode. We show that the solid Ca(OH)2 product readily decomposes and reacts with SiO2 to form alite, the majority cementitious phase in Portland cement. Electrochemical calcination produces concentrated gas streams from which CO2 may be readily separated and sequestered, H2 and/or O2 may be used to generate electric power via fuel cells or combustors, O2 may be used as a component of oxyfuel in the cement kiln to improve efficiency and lower CO2 emissions, or the output gases may be used for other value-added processes such as liquid fuel production. Analysis shows that if the hydrogen produced by the reactor were combusted to heat the high-temperature kiln, the electrochemical cement process could be powered solely by renewable electricity.
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Liu X, Li F, Peng P, Licht G, Licht S. Efficient Electrocatalytic Synthesis of Ammonia from Water and Air in a Membrane‐Free Cell: Confining the Iron Oxide Catalyst to the Cathode. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900667] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Xinye Liu
- Department of Chemistry The George Washington University Washington DC 20052 USA
| | - Fang‐Fang Li
- Department of Chemistry The George Washington University Washington DC 20052 USA
| | - Ping Peng
- Department of Chemistry The George Washington University Washington DC 20052 USA
| | - Gad Licht
- Department of Chemistry The George Washington University Washington DC 20052 USA
| | - Stuart Licht
- Department of Chemistry The George Washington University Washington DC 20052 USA
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Gao M, Deng B, Chen Z, Tao M, Wang D. Cathodic reaction kinetics for CO2 capture and utilization in molten carbonates at mild temperatures. Electrochem commun 2018. [DOI: 10.1016/j.elecom.2018.02.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Johnson M, Ren J, Lefler M, Licht G, Vicini J, Licht S. Data on SEM, TEM and Raman Spectra of doped, and wool carbon nanotubes made directly from CO 2 by molten electrolysis. Data Brief 2017; 14:592-606. [PMID: 28879217 PMCID: PMC5573802 DOI: 10.1016/j.dib.2017.08.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 08/09/2017] [Accepted: 08/15/2017] [Indexed: 11/25/2022] Open
Abstract
This SEM, TEM and Raman Spectra and economic calculations data provides a benchmark for carbon nanotubes synthesized via molten electrolyte via the carbon dioxide to carbon nanotube (C2CNT) process useful for comparison to other data on longer length C2CNT wools; specifically: (I) C2CNT electrosynthesis with bare (uncoated) cathodes and without pre-electrolysis low current activation. (II) C2CNT Intermediate length CNTs with intermediate integrated electrolysis charge transfer. (III) C2CNT Admixing of sulfur, nitrogen and phosphorous (in addition to boron) to carbon nanotubes, and (IV) Scalability of the C2CNT process. This data presented in this article are related to the research article entitled “Carbon Nanotube Wools Made Directly from CO2 by Molten Electrolysis: Value Driven Pathways to Carbon Dioxide Greenhouse Gas Mitigation” (Johnson et al., 2017) [1].
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Affiliation(s)
- M Johnson
- Dept. of Chemistry, George Washington University, Washington, D.C. 20052, United States
| | - J Ren
- Dept. of Chemistry, George Washington University, Washington, D.C. 20052, United States
| | - M Lefler
- Dept. of Chemistry, George Washington University, Washington, D.C. 20052, United States
| | - G Licht
- Dept. of Chemistry, George Washington University, Washington, D.C. 20052, United States
| | - J Vicini
- Dept. of Chemistry, George Washington University, Washington, D.C. 20052, United States
| | - S Licht
- Dept. of Chemistry, George Washington University, Washington, D.C. 20052, United States
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