查找使用阿拉丁产品的科研文献

Solubility and diffusion behavior of compressed CO2 in polyurethane oligomer

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.

Fabrication of Ag2S electrode for CO2 reduction in organic media

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.

CO2-philic WS2 laminated membranes with a nanoconfined ionic liquid

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.

Mechanochemical reactions of alkali borohydride with CO2 under ambient temperature

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.

CNT network crosslinked by metal Co2+ for stabilizing SnO2 anodes

Jingyi Zou,Xiaogang Sun,Rui Li,Qiang He

Porous carbon materials are considered potential replacements for metal carriers in Li–SnO 2 batteries. Here, a 3D hierarchical porous carbon nanotube (CNT) scaffold was used as a collector to host SnO 2 . The novel collector comprised Co 2+ -doped porous carbon (PC) slices and a CNT network. The new Co–PC/CNT electrode demonstrated a high loading capacity of SnO 2 , accommodated the volume expansion of SnO 2 , and prevented its aggregation. Co played an important role in improving the initial discharge capacity and coulombic efficiency of the electrode. The SnO 2 –Co–PC/CNT electrodes exhibited outstanding electrochemical performance. The first-discharge specific capacity reached 2067 mAh·g −1 , and the utilization rate of active materials reached 82.92% at a current density of 100 mAh·g −1 . After 100 cycles, the specific discharge capacity remained greater than 698 mAh·g −1 , with a coulombic efficiency of 99.53%.

CO2-switchable vesicles-network structure transition and drug release property

Wenmeng Duan,Xianwu Jing,Jiang Tan,Minmin Tao,Lu Wang,Hongsheng Lu

Carbonate shell regulates CuO surface reconstruction for enhanced CO2 electroreduction

Ma Xianhui,Yang Tong,He Dayin,Gao Xiaoping,Jiang Wei,Li Deming,Sun Yuanhua,Lin Xingen,Xu Jie,Wang Huijuan,Tai Xiaolin,Lin Yue,Yao Tao,Zhou Huang,Wu Yuen

The surface structure of catalysts greatly impacts the performance of the electrochemical CO 2 reduction reaction. However, the reconstruction caused by applied potential can affect the surface structure and is difficult to control. Here, inspired by drug capsules with extended-release structures, we construct a water-soluble carbonate shell on metal oxide catalysts. The shell acts as a protective coating, effectively slowing down the surface evolution process of the catalyst from high to low valence state under the applied electric field. Therefore, by tuning the shell thickness and dissolution rates, the surface reconstruction can be regulated, steering it towards the formation of an abundant low-coordinated structure. This strategy could promote the generation of Cu(0) with rich grain boundaries and small particles. The C 2+ Faradaic efficiency was 82.8 ± 2.2% with a current density of 2.0 A cm −2 , exceeding the performance of conventional CuO catalysts. Ex situ and in situ characterizations indicate that these generated surface structures enhance *CO intermediate stabilization and C–C coupling. Our approach for regulating surface reconstruction can be applied to other catalysts, such as ZnO, In 2 O 3 , SnO 2 and Bi 2 O 3 , elevating their selectivity towards CO and formate.

Carbonic Anhydrase Immobilized by ZnO Nanoparticles for Catalytic CO2 Conversion

Liu Lian,Wang Xin,Gao Zixin,Zhan Yue,Yao Mengqin,Bao Jia

Carbon capture, utilization, and storage (CCUS) has emerged as a critical strategy in combating climate change and global warming. Carbonic anhydrase (CA) exhibits exceptional potential as a biocatalyst for CCUS processes due to its remarkable ability to accelerate CO 2 hydration. In this study, CA was immobilized on ZnO nanocarriers of varying morphologies. The optimal immobilization conditions and enzymatic properties of the immobilized CA were investigated, followed by catalytic CO 2 uptake and mineralization experiments. The immobilization process resulted in several improvements: enhanced overall thermal stability, an elevated optimal reaction pH of 8.50 (compared to 8.00 for free CA), retention of 84.98% original activity after 30 days of storage at 4 °C, and preservation of 85.36% initial activity after five recycling cycles. While the affinity between immobilized CA and its substrate increased, a decrease in activity was observed. The Michaelis constant (Km) for immobilized and free CA were determined to be 17.22 mM and 34.92 mM, respectively, with corresponding catalytic efficiency (Kcat/Km) of 20.49 M −1 -S −1 and 148.91 M −1 -S −1 . The catalytic performance of immobilized CA was investigated by carrying out the CO 2 adsorption assay. Notably, the catalytic efficiency of immobilized CA in CO 2 absorption and mineralization under various conditions was significantly enhanced. Graphical

CO2 hydrogenation to methanol over the copper promoted In2O3 catalyst

Rui Zou,Chenyang Shen,Kaihang Sun,Xinbin Ma,Zhuoshi Li,Maoshuai Li,Chang-Jun Liu

The metal promoted In 2 O 3 catalysts for CO 2 hydrogenation to methanol have attracted wide attention because of their high activity with high methanol selectivity. However, there was still no experimental confirmation if copper could be a good promoter for In 2 O 3 . Herein, the Cu promoted In 2 O 3 catalyst was prepared using a deposition-precipitation method. Such prepared Cu/In 2 O 3 catalyst shows significantly higher CO 2 conversion and space time yield (STY) of methanol, compared to the un-promoted In 2 O 3 catalyst. The loading of Cu facilitates the activation of both H 2 and CO 2 with the interface between the Cu cluster and defective In 2 O 3 as the active site. The Cu/In 2 O 3 catalyst takes the CO hydrogenation pathway for methanol synthesis from CO 2 hydrogenation. It exhibits a unique size effect on the CO adsorption. At temperatures below 250 °C, CO adsorption on Cu/In 2 O 3 is stronger than that on In 2 O 3 , causing higher methanol selectivity. With increasing temperatures, the Cu catalyst aggregates, which leads to the formation of weak CO adsorption site and causes a decrease in the methanol selectivity. Compared with other metal promoted In 2 O 3 catalysts, it can be concluded that the catalyst with stronger CO adsorption possesses higher methanol selectivity.

A Hydrogel Electrolyte-Based Zn−CO2 Battery with Improved Life

Xinyi Sun,Zhang Wen,Yiwen Liu,Min Zhang,Wei Li,Chuanchao Sheng,Sixie Yang,Haoshen Zhou,Ping He

Environmental-friendly aqueous Zn−CO 2 batteries present bifunctional potentials of achieving carbon neutrality and energy storage. Nonetheless, anode corrosions derived from H 2 O molecules and high risks of volatilization and leakage hinder the advancement of Zn−CO 2 batteries. In this work, polyvinyl alcohol (PVA)-based hydrogel electrolyte with fast ion diffusion kinetics, high mechanical strength, and flexibility is developed to replace liquid electrolyte. Since hydroxyl radicals in the polymer chain can interact with H 2 O and Zn 2+ , electrode corrosion from free H 2 O and active H 2 O around Zn 2+ is significantly inhibited, facilitating the uniform deposition of Zn 2+ cations. The introduction of an ionic liquid plasticizer further enhances the interaction between Zn 2+ and polymer backbone, as well as amorphous extent of the electrolyte. The hydrogel electrolyte possesses adequate self-healing ability, whose ionic conductivity reaches 7.95 × 10 −3 S cm −1 . The symmetric Zn metal batteries containing the electrolyte remain steady for >2000 h under different current densities. Furthermore, the Zn−CO 2 battery based on Ru nanoparticles cathode and hydrogel electrolyte realizes a discharge capacity of 6028 mAh g −1 and stable cyclicity for 90 times. The reaction path of hydrogel electrolyte-based Zn−CO 2 battery is that CO 2 is reduced to ZnCO 3 and C species followed by reversible decomposition of discharge products on recharge.

CO2-Assisted Back-Extraction Method for Ionic Liquid Biphasic Systems

Zhenkang Li,Zhiping Wang,Qiwei Yang,Zhiguo Zhang,Yiwen Yang,Qilong Ren,Huabin Xing

Ionic liquid (IL)-mediated extraction methods have drawn much attention due to their reduced environmental impact and improved extraction efficiencies compared to traditional separation methods. However, one long-standing challenge in the application of IL-based extraction processes is the difficulty in recovering high-boiling solutes from the IL phase due to the negligible vapor pressure of ILs and the strong interaction between solutes and ILs. In this study, a new CO2-assisted back-extraction method was developed for the recovery of high-boiling solutes from the IL phase based on the reversible chemical absorption and/or strong physical interaction of CO2 with ILs. We found the distribution coefficient (D) of the typical solute δ-tocopherol in the [P4444][Pro]/DMSO–hexane biphasic system significantly decreased from 10.38 to 2.42 after the introduction of CO2, which greatly reduced the required solvent consumption and the number of back-extractions required for tocopherol recovery. For example, the number of back-extractions required for the recovery of 90% of the tocopherols from the [P4444][Pro]/DMSO–hexane biphasic phase decreased from 24 to 5 with the aid of CO2 absorption, along with a decrease in solvent consumption by approximately 80%. The effects of the structure of the IL, the loading of CO2, the type of cosolvents, and the temperature of the CO2-assisted back-extraction processes were investigated in this study. This proof-of-concept study demonstrates the great potential of CO2-assisted back-extraction as a green method for the efficient recovery of high-boiling solutes from the IL phase.

Pebax–polydopamine microsphere mixed-matrix membranes for efficient CO2 separation

Yuanyuan Liu,Xueqin Li,Yun Qin,Ruili Guo,Jianshu Zhang

Novel facilitated-transport mixed-matrix membrane (MMM) were prepared through the incorporation of polydopamine (PDA) microspheres into a poly(amide- b -ethylene oxide) (Pebax MH 1657) matrix to separate CO 2 –CH 4 gas mixtures. The Pebax–PDA microsphere MMMs were characterized by Fourier transform infrared spectroscopy, scanning electron microcopy, X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The PDA microspheres acted as an adhesive filler and generated strong interfacial interactions with the polymer matrix; this generated a polymer chain rigidification region near the polymer–filler interface. Polymer chain rigidification usually results in a larger resistance to the transport of gas with a larger molecular diameter and a higher CO 2 –CH 4 selectivity. In addition, the surface of PDA microspheres contained larger numbers of amine, imine, and catechol groups; these were beneficial to the improvement of the CO 2 separation performance. Compared with the pristine Pebax membrane, the MMM with a 5 wt % PDA microsphere loading displayed a higher gas permeability and selectivity; their CO 2 permeability and CO 2 –CH 4 selectivity were increased by 61 and 60%, respectively, and surpassed the 2008 Robeson upper bound line. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44564.