JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2020
·Vol. 31
·期 12
·9057-9064
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IF 2.22
Zhao Jingkui,Liu Xiansong,Kan Xucai,Chen Zuhua,Liu Chaocheng,Wang Wei,Lv Qingrong,Huang Jingwen,Shazeda Mudssir
In this study, novel Ni–Cu–Zn ferrites with the chemical formula [Ni 0.6 Zn 0.4 ][Cu 0.2 Co x Fe 1.8− x ]O 4 ( x = 0, 0.05, 0.10, 0.15, 0.20, 0.25) doped with Co 2+ ions were designed and manufactured by standard solid-state reaction method. The magnetic properties, surface characteristics, and ion occupancy of ferrites were studied by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM), and we explained the different mechanisms of the results and the relationship between magnetic properties and microstructures. For the obtained samples, cobalt ions entered the lattice, and all samples were characterized as spinel structures. As the doping amount of Co 2+ ions increases, the lattice constant and volume of the sample also increases. With an appropriate doping level, Co 2+ ions-doped Ni–Cu–Zn ferrites can maintain higher saturation magnetization, higher magnetic permeability, and lower hysteresis loss. When x ≤ 0.1, the saturation magnetization M s increases significantly as the doping amount of Co 2+ ions increases, but when x > 0.1, the value decreases. The experimental results show that the saturation magnetization value is 118.08 emu/g, the magnetic permeability value is 39.47 H/m, and the hysteresis loss is 1.192 mW/cm 3 at an optimum doping amount. Therefore, the sample achieves the best magnetic properties when the doping amount is 0.1.
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SEPARATION SCIENCE AND TECHNOLOGY
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2019
·
IF 1.354
Airong Li,Dan Luo,Lele Jiang,Jie Wang,Yi Zhou
A series of experiments on CO2 hydrate formation were carried out in the presence of titanium dioxide (TiO2), silicon dioxide (SiO2), multi-walled carbon nanotubes (MWNTs) nanoparticles. The effects of these nanoparticles on induction time, final gas consumption, and gas storage capacity have been investigated at the temperature of 274.15 K and the initial pressure of 5.0 MPa.g. The induction time of CO2 hydrate formation was remarkably shortened to 12.5 min in the presence of 0.005 wt% MWNTs nanoparticles. The high thermal conductivity and heat capacity of MWNTs nanoparticles presented better heat transfer, and large surface area provided more suitable sites for heterogeneous nucleation of CO2 hydrate.
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高影响因子
LANGMUIR
·
2019
·
IF 3.683
Zidong Zhang,Yuming Tu,Hui Yu,Weidong Liu,Zhiyong Zhou,Zhongqi Ren
Extraction is a common approach to separating aromatics and alkanes, but solvent recovery remains an issue. The polarity, hydrophobic/hydrophilic balance, and other properties of switchable solvents can be reversibly changed in the presence of various triggers, and taking advantage of this property can greatly simplify the process of solvent recovery. In this work, quaternation and anion exchange were used to prepare several switchable solvents by introducing OH– ions to derivatives of the amidine compound 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The resulting compounds exhibited reversible switching in response to exposure to CO2. Using toluene/n-heptane as a model hydrocarbon mixture, a reversible phase change extraction process was established. Among the four switchable solvents prepared, [C2DBU]OH showed the highest selectivity value and so was used to investigate the effect of various parameters on hydrocarbon separation. The extraction process was found to rapidly reach equilibrium when a two-phase system was generated by bubbling CO2 through the extraction mixture. Increasing the proportion of the solvent increased the selectivity for toluene, while a 1:1 ratio between the solvent and the toluene/n-heptane mixture enhanced the extraction. Increasing the initial toluene concentration reduced the selectivity for toluene, with a value of 5.97 at a toluene concentration of 20%. The switchable solvent recovered its initial state when heated at 60 °C for 1 h. Upon being reused after removal of CO2, the solvent exhibited poor separation characteristics, although the selectivity coefficient remained constant at approximately 3.1 during 10 regenerations. Finally, the mechanism of the switchable solvent effect and modeling of experimental data were investigated.
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PubMed
高影响因子
ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Fajun Li
Metals have proved to be cracking catalysts for electrochemical reduction of CO 2 to formate (ERCO 2 F), but they suffer from a high overpotential caused by weak adsorption of CO 2 . As far as we know, N-containing polymers, with N atoms lowering the activation energy through efficient trapping of CO 2 , can make contributes to ERCO 2 F. Here, a composite electrode of metal and N-containing conjugated polymer at the interface was used for CO 2 reduction. It exhibited superior Faradaic efficiency (94% ± 1%) and space time yield (306 ± 14 μmol h −1 cm −2 ) at the electrolytic potential of −1.70 V for electrochemical reduction of CO 2 to formate. Polyaniline film was obtained by potentiostatic reduction of pre-completed polyaniline nanowires from polymerizing aniline on Ni foam. Then the spontaneous oxidation of base polyaniline was used to promote the reduction of tin deposition on its surface.
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ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Yunfei Chen,Mingyong Wang,Songle Lu,Jiguo Tu,Shuqiang Jiao
s Electrochemical conversion of CO 2 to carbon in molten salts is a promising route for the high-value utilization of greenhouse gases . Low graphitization degree of carbon materials is the limiting issue for potential applications. In the past, catalytic effect for the electrochemical conversion of CO 2 was not achieved in molten salts due to carbon coverage on heterogeneous solid electrode. A novel and feasible homogeneous catalytic strategy by soluble NaVO 3 in carbonate molten salt was proposed for the enhanced electrochemical conversion of CO 2 to carbon with high graphitization degree. It was found that graphite consisting of carbon nanotubes and sheets were more easily produced by adding NaVO 3 into molten salt. The graphitization degree of carbon products was obviously improved and I D / I G value was only 0.428. During CO 2 electrolysis, vanadate in the form of V 2 O 7 4− will be co-electroreduced to V 2 O 3 . Meanwhile, V 2 O 7 4− ions can be regenerated by the spontaneous reaction between the newly-formed V 2 O 3 and carbonate, which also accelerates the production of graphite. Therefore, a continuous homogeneous in-situ catalytic cycle was achieved for the enhanced graphitization conversion of CO 2 . It provides a novel and effective way to prepare carbon materials with high graphitization degree from CO 2 .
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ACS Sustainable Chemistry & Engineering
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2019
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IF 6.97
Jinsong Shi,Nanfu Yan,Hongmin Cui,Jianguo Xu,Yuewei Liu,Shaowei Zhang
Because of their high stability, low cost, and tunable porosity, porous carbons are of great interest as CO2 adsorbents. The influences of porosity and heteroatom doping on CO2 adsorption depend on the specific adsorption conditions. In the current work, nitrogen and sulfur co-doped carbons were prepared with the assistance of an NaCl template, and the effects of different physicochemical parameters on CO2 adsorption at 20 bar were investigated. The co-doped carbons were synthesized with sodium lignosulfonate as the starting material and urea as the nitrogen source. The material showed a high specific surface area and pore volume of 973 m2/g and 0.50 cm3/g, respectively. Sulfur-doped carbons were also prepared without the addition of urea. Sulfur doping demonstrated positive effects on CO2 adsorption at a low pressure. The sulfur-doped carbons showed adsorption properties similar to those of the co-doped carbons. The CO2 uptake at 298 K and 20 bar was in the range of 4.3–7.5 mmol/g. The experiment results also revealed that the uptake at 20 bar correlated to the specific surface area of the carbon, while the doped heteroatoms only had secondary influences.
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NEW JOURNAL OF CHEMISTRY
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2019
·Vol. 43
·期 44
·17267-17274
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IF 3.069
Pengcheng Su,Xu Zhang,Zehai Xu,Guoliang Zhang,Chong Shen,Qin Meng
Recently, great improvements have been achieved in the fabrication of adsorbents. However, designing adsorbents with high adsorption capacity and superior selectivity still remains a big challenge. In the present study, a novel cost effective NH2-HCP adsorbent for toxic dyes and CO2/N2 separation was facilely synthesized through the one-step Friedel–Crafts alkylation reaction of m-phenylenediamine (MPD). The adsorption process under different adsorption parameters, namely, contact time and initial dye concentration were investigated in detail to explore the adsorption characteristics of the NH2-HCPs. Moreover, the experimental results demonstrated that the equilibrium adsorption isotherm and adsorption kinetics for anionic dye adsorption onto the NH2-HCPs fitted well with the Langmuir model and pseudo-second-order model, respectively. With a mesoporous structure and a high density of active amino groups, the amino-functionalized hypercrosslinked polymers (NH2-HCPs) not only showed an unprecedented adsorption capacity of 3290 mg g−1 for the anionic dye X-3B and almost no adsorption toward the cationic dye, but also possessed an excellent CO2/N2 selectivity of 122.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2019
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IF 5.107
Meidi Wang,Kaidong Quan,Xiaohong Zheng,Yu Cao,Xiangyu Cui,Ming Xue,Fusheng Pan
Two-dimensional (2D) covalent organic nanosheets (CONs) present versatile 2D materials, which hold great promise in mixed matrix membranes. The facile synthesis of CONs for the fabrication of mixed matrix membranes represents the development trend. Herein, mixed matrix membranes with facilitated transport ability were prepared based on self-exfoliated covalent organic nanosheets (CONs) and poly(ether-block-amide) (Pebax® MH 1657) matrix. The self-exfoliated TpDT CONs were facilely synthesized via Schiff base condensation reaction between 1,3,5-Triformylphloroglucinol (Tp) and 3, 5-diamino-1,2,4-triazole (DT). Abundant amine groups on TpDT CONs skeleton served as facilitated transport carriers to promote the transport of CO 2 by reversible nucleophilic addition reactions. And the highly ordered channels of TpDT CONs allowed the rapid transportation of CO 2 molecules to reach the facilitated transport carriers. Moreover, the incorporated TpDT CONs disturbed the packing of the Pebax chains by the intervention effects and increased the chain mobility. The facilitated transport carriers from TpDT CONs and the optimized structure endowed the as-prepared membranes with elevated permeance and selectivity. Specially, the Pebax-TpDT/PVDF membranes with 1 wt% TpDT CONs achieved an optimum CO 2 /CH 4 separation performance with a separation factor of 36.0 and a CO 2 permeance of 142.3 GPU, which were increased by 68% and 131%, respectively, compared with the pristine Pebax membrane.
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MICROPOROUS AND MESOPOROUS MATERIALS
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2019
·
IF 4.182
Yinpeng Wang,Junqi Nie,Cuifen Lu,Feiyi Wang,Chao Ma,Zuxing Chen,Guichun Yang
Polyimidazolium salts are a class of important catalysts for CO 2 cycloaddition with epoxides. However, initiator like azoisobutyronitrile or metal catalyst is often required to promote their synthetic process. Therefore, developing a clean route to synthesize polyimidazolium salts is still highly desirable. In this study, three crosslinked polymers PIM1, PIM2 and PIM3 containing imidazolium unit were constructed via nucleophilic substitution reaction of 1,3,5,7-tetrakis (4-(imidazole-1-yl)phenyl)adamantane and benzyl bromides. The structure and composition of the polymers were characterized by CP/MAS 13 C NMR, FT-IR and XPS. Different porosities were observed for PIMs, and PIM2 has a larger BET surface are than that of PIM1 and PIM3. Accordingly, the polymeric imidazolium salt PIM2 shows superior activity for catalyzing cyclic addition of CO 2 with a variety of epoxides without any solvent or cocatalyst, giving the cyclic carbonates in excellent yields. In addition, PIM2 shows high stability and easy recyclability.
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JOURNAL OF CATALYSIS
·
2022
·
IF 8.047
Jing Huang,Jiawei Dai,Jiannan Zhu,Rong Chen,Xiaoqi Fu,Hongfang Liu,Guangfang Li
Electrocatalytic reduction of CO 2 (CO 2 RR) represents a promising approach to reduce CO 2 emission and generate value-added chemicals. Herein, we developed bimetallic Au-Cu gradient alloy nanostructures (AuCu-g) comprising of ultrathin Cu-rich alloy surface and Au-rich alloy core as electrocatalyst via a facial solvothermal method. Impressively, the AuCu-g can stably generate a considerable amount of C 2 H 4 with faradaic efficiency (FE) ∼20 % at a low limiting potential of −0.4 V versus reversible hydrogen electrode (RHE) due to its unique gradient structure and multi-component tandem effect. The potential-dependent in situ Raman spectrum indicated an enhanced *CO adsorption strength and a remarkable CO intermediate generation over Au-Cu gradient alloy at low overpotentials during CO 2 reduction process. This work shines a light for developing mutilmetallics toward efficient CO 2 RR.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2022
·
IF 9.136
Chaohui He,Peng Zhang,Yong Wang,Yujuan Zhang,Tuoping Hu,Libo Li,Jinping Li
The selective removal of carbon dioxide (CO 2 ) from acetylene (C 2 H 2 ) is an important separation process in the petrochemical industry, but is challenging due to the similar physicochemical properties of the two gases. Using CO 2 -selective adsorbents that have preferential affinity for CO 2 over C 2 H 2 in pressure swing adsorption was deemed a promising separation method for the separation of CO 2 /C 2 H 2 mixtures. Herein, we report an ultramicroporous metal-organic framework, Y-bptc, to achieve efficient separation of CO 2 /C 2 H 2 through thermodynamic and kinetic synergetic effects. The unique cage-type structure interconnected by small windows exhibits high adsorption capacity for CO 2 while efficiently impeding adsorption diffusion of C 2 H 2 , which was proved by the single-component equilibrium and kinetic adsorption curves. Grand canonical Monte Carlo (GCMC) molecular calculations further show that the µ 3 -OH − of the framework have a stronger adsorption affinity for CO 2 through forming hydrogen bonds. Breakthrough experiments using Y-bptc as a CO 2 -selective adsorbent proved that high-purity C 2 H 2 (>99%) could be directly produced from one-step separation of CO 2 /C 2 H 2 (1/1, v/v) mixtures, which greatly reduced the separation process and energy consumption. In addition, the structure of Y-bptc due to the high charge density of the Y6 cluster has high stability under humid and high-temperature conditions adding to the application possibility in industry.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2022
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IF 9.136
Lihua Han,Jian Mao,An-Quan Xie,Yunzheng Liang,Liangliang Zhu,Su Chen
Energy and freshwater, as natural and important strategic resources, are the lifeblood and basic security of economic and social development. Freshwater production consumes vast energy, and vice versa. It is rare and still a significant challenge in the rational design of implementation for efficient clean water and chemical fuel production via solar-thermal technology, reconciling the water-energy contradiction. Herein, we demonstrated a new double-stage solar catalytic membrane distillation (DSCMD) system, integrating photocatalyst into the photothermic electrospun film that is imparted with the water feeding, photothermic conversion and photocatalysis functions, which simultaneously realized the stable freshwater and enhanced clean fuels production. The photothermal/catalytic materials synergistically harvest photons for localized heat generation, which also acts on catalytically active sites to enhance the yield of vapor and CO, so as to maximize the utilization of solar energy. As a result, the overall freshwater collection rate of 1.45 kg m -2 h −1 with the solar-to-water efficiency of up to 90.6 % and enhanced CO evolution rate of 21.29 μmol g cat −1 h −1 from CO 2 photoreduction are achieved by more effective vapor transportation and latent heat recovery, superior to the traditional photothermal membrane distillation systems, providing an alternative opportunity for sustainably alleviating the freshwater and energy shortage.
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