Energy & Environmental Science
·
2019
·Vol. 12
·期 8
·2455-2462
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IF 33.25
Zhenglei Yin,Hanqing Peng,Xing Wei,Huan Zhou,Jun Gong,Mingming Huai,Li Xiao,Gongwei Wang,Juntao Lu,Lin Zhuang
The electrochemical conversion of CO2 to fuels or chemicals is an attractive approach that can combine sustainable energy utilization and carbon recycling, but its practicability is still vague, because the CO2 reduction reaction (CO2RR) has hitherto been mostly studied in electrolyte solutions, with small current densities limited by the solubility of CO2. An important and urgent task is thus to develop CO2 electrolyzers that can demonstrate the feasibility of the large-scale conversion of CO2, in particular analogs of water electrolyzers using polymer electrolyte based gas-diffusion electrodes. Here we report a high-performance CO2 electrolyzer making use of alkaline polymer electrolytes (APEs). A highly conductive and stable APE, quaternary ammonia poly(N-methyl-piperidine-co-p-terphenyl) (QAPPT), was applied both as the membrane separator and the ionomer impregnating the gas-diffusion electrodes. Dry CO2 was fed into the Au cathode, with a faradaic efficiency of CO production (COFE) over 85%, and the oxygen evolution reaction (OER) occurred at the IrO2 anode fed with pure water. The cell was operated at temperatures up to 80 °C, and the current density reached 0.5 A cm−2 at 3 V at 60 °C. The stability of this electrolyzer was tested under 0.1 A cm−2, and the cell voltage remained stable at 2.25 V over 100 h, with the COFE staying at 90–95%.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2019
·
IF 7.149
Chenyu Xu,Jiahui Cai,Zhihua Wang,Mingjiang Ni,Kefa Cen,Yanwei Zhang
In this work, to achieve both clean energy production and carbon emission reduction, a united conversion to couple CO2 mineralization with thermochemical hydrogen production is proposed. Natural magnesium silicate minerals are used to fix CO2 in the form of carbonate minerals, whereas H2O is dissociated to produce H2 in the thermochemical cycle. The integration provides a new solution to the challenges of the high energy consumption and poor economic value of conventional CO2 mineralization processes, and the technical feasibility has been proven. Moreover, the energy economy and CO2 conversion capacity were investigated. Hydrolyzation and carbonation experiments were performed in a homemade reactor, and it was found that an optimal MgI2 hydrolyzation rate of 75% could be achieved without alkali consumption. A detailed simulation of the whole system was also developed. The optimal energy conversion efficiency of the cycle reached 47.6%, which is higher than most of the published theoretical energy efficiency values for sulfur–iodine thermochemical cycles. A modified calculation of the net energy requirement for CO2 mineralization was carried out. Finally, a comparison and an evaluation of the energy efficiencies were made based on the calculation. In the optimal case, the modified net energy requirement is 1.4 MJ/kg CO2, which means that this method is competitive compared to those of previous works.
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JOURNAL OF ELECTRONIC MATERIALS
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2019
·Vol. 48
·期 7
·4653-4659
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IF 1.676
Lei Dongling,Ma Shiyu,Lu Youcai,Liu Qingchao,Li Zhongjun
A rechargeable Li-CO 2 battery has been considered to be a promising battery system due to its high-energy density and the utilization of carbon dioxide (CO 2 ). However, the high overvoltage caused by the discharge product Li 2 CO 3 hinders the development of Li-CO 2 batteries. In this work, α-MnO 2 nanowires obtained via a redox reaction have been employed as the cathode catalyst in the Li-CO 2 battery, which can provide sufficient catalytic sites for CO 2 evolution and tune the cathode structure for the uniform distribution of Li 2 CO 3 and C on the cathode. The Li-CO 2 battery with an MnO 2 /carbon nanotube (CNT) cathode exhibits significantly reduced overpotential, and could be operated for 50 cycles with a fixed capacity of 1000 mAh g −1 and 6 cycles of full discharge–charge tests at a current density of 100 mA g −1 .
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JOURNAL OF APPLIED POLYMER SCIENCE
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2019
·Vol. 136
·期 32
·47844
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IF 2.188
Jingqian Deng,Zuolong Liu,Zhongjie Du,Wei Zou,Chen Zhang
A polymer foam material with both the open-cell porous structure and the polyethylenemine (PEI)-grafted inner face was constructed for CO 2 capture. The porous poly(tert-butyl acrylate) foam was first prepared via a concentrated emulsion polymerization, and then the carboxyl groups were introduced on the interface of porous polymer after the hydrolysis reaction. Subsequently, the surface of the foam was grafted with PEI, and finally the PEI-grafted porous polymer foam designed as a CO 2 capture material was obtained. The structures of the foams were characterized by infrared spectroscopy, EDS, and SEM. The CO 2 adsorption properties were measured by adsorption/desorption cycles. As a result, the polymer foam contained a large number of amine groups (13.9 wt % N), and therefore possessed a high CO 2 adsorption capacity (5.91 mmol g −1 at 40°C and 100 kPa). In addition, they also exhibited high CO 2 adsorption rate, good selectivity for CO 2 -N 2 separation, and good stability according to CO 2 cyclic adsorption/desorption test. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47844.
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CATALYSIS TODAY
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2018
·
IF 4.667
Pan Li,Shuang Zhu,Haifeng Hu,Lingju Guo,Tao He
Photocatalytic conversion of CO 2 into hydrocarbons by utilization of the solar energy is considered a promising approach to mitigate energy crisis and the environmental issues. Since the defects in a catalyst play an important role in CO 2 reduction, herein, the porous ZnO nanoplates with vacancy defects are synthesized by annealing ZnS(en) 0.5 precursor in air at different temperature. The defect amount in ZnO changes with the annealing temperature, resulting in different photocatalytic activity for CO 2 reduction. The related mechanism has been studied both experimentally and theoretically. Raman spectra and chemical composition of the obtained catalysts are used to determine the defects. Transient techniques are used to investigate the separation of photogenerated charge carriers. CO 2 adsorption capacity for different catalysts is also measured. First-principles calculation is used to study the adsorption and activation of CO 2 on the ZnO surface. We envision that this work may afford an efficient approach to develop the semiconductor photocatalysts with superior activity via defects engineering.
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MACROMOLECULAR CHEMISTRY AND PHYSICS
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2019
·Vol. 220
·期 12
·1900071
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IF 2.622
Diwei Yan,Sa Liu,Yong-Guang Jia,Lina Mo,Dawei Qi,Jin Wang,Yunhua Chen,Li Ren
Realizing the reversible transformation of the supramolecular hydrogels is essential for their application as smart materials. The reversible sol-gel transition of the polypseudorotaxane (PPR) hydrogels is achieved through adding a CO 2 -switchable guest molecule into the PPR hydrogel of poly(ethylene glycol) (PEG) and α-cyclodextrins (α-CDs). Alternating treatments with CO 2 and heating drive such reversible transition due to the competitive complexation as evidenced by 2D NOESY 1 H NMR and isothermal titration calorimetry as well as X-ray diffraction. The present work describes a straightforward way to obtain switchable PPR hydrogels triggered by a compatible stimulus of CO 2 . These stimuli-responsive PPR hydrogels have potential applications as biomaterials.
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Polymers
·
2019
·Vol. 11
·期 6
·994
·
IF 3.164
Longming Jin,Jianyun Gan,Gang Hu,Long Cai,Zaiquan Li,Lihua Zhang,Qiang Zheng,Haibo Xie
Cellulose films are regarded as sustainable materials having wide applications in food packaging, separation, etc. Their preparation substantially relies on sufficient dissolution. Herein, various celluloses adequately dissolved in a new solvent system of carbon dioxide,1, 8-diazabicyclo [5.4.0] undec-7-ene and dimethyl sulfoxide (CO2/DBU/DMSO) were made in to films using different regeneration reagents. The films regenerated from ethanol and methanol presented homogeneous and smooth surfaces, while those from 5 wt % NaOH (aq.) and 5 wt % H2SO4(aq.) showed rough surfaces, as analyzed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The films regenerated from 5 wt % NaOH (aq.) and 5 wt % H2SO4(aq.) rendered cellulose II structures, while those regenerated from alcohols had amorphous structures as evidenced using fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) results. The films made of microcrystalline cellulose had a good light transmittance of about 90% at 800 nm with a tensile strength of 55 MPa and an elongation break of 6.5%, while those from wood pulp cellulose demonstrated satisfactory flexibility with a tensile strength of 91 MPa and an elongation break of 9.0%. This research reports a simple, environmental, and sustainable method to prepare cellulose films of good mechanical properties.Keywords:CO2;cellulose dissolution;cellulose films;regeneration
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JOURNAL OF POROUS MATERIALS
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2019
·Vol. 26
·期 6
·1831-1838
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IF 1.947
Mutyala Suresh,Yu Ya-Dong,Jin Wei-Guang,Wang Zhi-Shuo,Zheng Deng-Yue,Ye Chun-Rong,Luo Binbin
Composite material, tetraethylenepentamine (TEPA) incorporated UiO-66 was prepared by impregnation method to study CO 2 capture in a fixed bed reactor, atmospheric pressure. All synthesized adsorbents were characterized using PXRD, N 2 adsorption–desorption isotherms, FT-IR, TGA, SEM, and Elemental analysis. Characterization results have revealed that incorporated TEPA was present within pores of UiO-66. CO 2 adsorption was higher on TEPA incorporated UiO-66 compared to UiO-66. It was due to the chemical interaction between –NH 2 and CO 2 . High CO 2 adsorption capacity 3.70 mmol g −1 was obtained on 30TEPA/UiO-66 at 75 °C, 1 bar. Because of more flexibility and high dispersive nature of TEPA at this temperature. The same CO 2 adsorption capacity was obtained in each adsorption cycle without decomposition of the amine on 30TEPA/UiO-66. Avrami adsorption kinetic model has suggested adsorption of CO 2 on composite material was chemical adsorption and deactivation model suggested an initial rate of adsorption was higher on TEPA incorporated UiO-66.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2018
·Vol. 136
·期 8
·47100
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IF 1.901
D. Hu,L. Yan,T. Liu,Z. Xu,L. Zhao
In CO 2 -assisted polyurethane (PU) foaming, the solubility and diffusion coefficient of CO 2 is vitally important to the cell nucleation and growth. This work is aimed at the effect of molecular weights ( M n ) and crosslinking densities ( V e ) on the solubility and diffusion coefficient of CO 2 in PU oligomers. A series of PU oligomers with different M n and V e were synthesized. The solubility and diffusivity of CO 2 in PU oligomers were measured experimentally in the temperature from 80 to 140 °C and with pressures up to 15 MPa. It was shown that the solubility and diffusion coefficients of CO 2 was decreased 20.5 and 21.0%, respectively, with the M n increasing from 5864 to 153,754 g mol −1 at 80 °C, 15 MPa. The solubility and the diffusion coefficient also decreased 11.1 and 38.0% as the V e was increased from 64 to 1493 mol m −3 . Furthermore, the diffusion mechanism of CO 2 in PU oligomers was explored via molecular dynamics simulations. The results indicated that the calculated diffusivity of CO 2 showed the same changing trend as the experimental values, and the smaller M n or crosslinking degree contributed to an increase in fractional free volume and stronger polymer–CO 2 interactions. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47100.
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IONICS
·
2018
·Vol. 25
·期 4
·1921-1927
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IF 2.347
Shen Feng-xia,Shi Jin,Shi Feng,Chen Tian-you,Li Yun-fei,Li Qing-yuan,Dai Yong-nian,Yang Bin,Qu Tao
Electro-reduction of carbon dioxide (CO 2 ) to carbon monoxide (CO) has been extensively studied on metal and alloy electrodes for many decades. However, owing to their disadvantages of low current density and high over-potential, the practical application of these electrodes has been limited. Hence, it is highly desirable to explore new and high efficient electrode for CO 2 reduction to CO. Ag 2 S has been widely studied as electrode material in electrochemistry due to its unique properties, such as high conductivity, chemical stability, and easy to be prepared. In this work, we have fabricated an Ag 2 S electrode via electro-oxidation of Ag in aqueous solution. X-ray diffraction (XRD) and scanning electron microscope (SEM) confirm that Ag 2 S has been modified on Ag foil, which made the electrode surface roughness. And then, we have evaluated the performance of Ag 2 S electrode as the cathode for CO 2 reduction in propylene carbonate/tetrabutylammonium perchlorate. The cathodic current density reaches to 9.85 mA/cm 2 , with the faradic efficiency for CO formation remaining stable at 92% during 4 h long-term electrolysis.
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Journal of Materials Chemistry A
·
2018
·Vol. 6
·期 34
·16566-16573
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IF 9.931
Danke Chen,Wensen Wang,Wen Ying,Yi Guo,Donghui Meng,Youguo Yan,Rongxin Yan,Xinsheng Peng
The modern global climate change and global warming of Earth make it an urgent need to develop emerging CO2 capture and storage techniques. Herein, we first reported the use of WS2 nanosheets to construct laminated membranes for CO2 separation. However, the WS2 membrane showed poor CO2 separation performance with Knudsen selectivities for N2/CO2 (1.28), CH4/CO2 (1.72) and H2/CO2 (4.96). To improve the performance, an ionic liquid (IL) 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM][BF4]) with high CO2 solubility and practically no vapour pressure was used for filling the nanochannels of the WS2 membrane. Compared to the bulk IL, the nanoconfined IL exhibits higher freezing temperature, shift of vibration bands and higher interaction energy between CO2 and ILs. Besides, the prepared WS2 laminated membrane with the nanoconfined ionic liquid shows excellent selectivities for CO2/N2 (153.21), CO2/CH4 (68.81) and CO2/H2 (13.56) in single gas measurements as well as good CO2 permeance due to the nanoconfinement of the IL. The simulation results further confirmed and explained the CO2 separation mechanism. It indicates that the nanoconfinement of ILs into the nanochannels of two-dimensional materials is a novel way to achieve CO2-philic membranes to efficiently separate CO2 from other light gases.
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JOURNAL OF SOLID STATE CHEMISTRY
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2019
·
IF 2.291
Wei Zhu,Juan Zhao,Lu Wang,Yun-Lei Teng,Bao-Xia Dong
Many efforts have been made to study the reactions of the borohydride with CO 2 in solution. However, it is scarce to achieve the hydrogenation of CO 2 using borohydrides as hydrogen source by the solid-gas direct reaction in the condition of ball milling under ambient temperature. Herein, we investigated the solid-gas noncatalytic reaction of ABH 4 (A = Li or Na) with CO 2 under mechanochemical conditions for the first time. It is found that hydrogen and trimethylborane are formed in the gas phase, as well as borate , formate, and methoxy species are formed in the solid phase.
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