ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Haiyang Zhang,Ruili Guo,Jinli Zhang,Xueqin Li
Mixed matrix membranes (MMMs) have exhibited advantages in overcoming the trade-off effect, although it is still intensively demanded in the design of multifunctional fillers to improve CO2 separation performance. At present, MMMs with transport channels present an effective strategy to obtain ultrahigh CO2 permselectivity. In this work, Pebax-based MMMs was fabricated by incorporating nanocapsules (NCs), whose exterior, interior and transverse shell surfaces contained abundant carboxylic acid groups. NCs, similar to vesicles in cells, provide favorable physical and chemical microenvironments to the constructed CO2 transport channels, enhancing the CO2 permselectivity via both a facilitated transport mechanism and a solution-diffusion mechanism. CO2 permselectivity of MMMs doped with 20 wt % NCs surpassed the 2008 Robeson limit; an increase in CO2 permeability was up to 1431 ± 35 Barrer for pure gas, which was a 362% enhancement from the pure membrane, and an increase of the CO2/CH4 and CO2/N2 ideal selectivities to 46 ± 1.4 and 69 ± 2.7, corresponding to 44% and 23% enhancements from the pure membrane, respectively. This study provides an ingenious strategy to enhance the gas permselectivity of MMMs.
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PubMed
高影响因子
NANO
·
2019
·
IF 1.293
Hongning Wang,Chao Xu,Yongsheng Zhou,Wenpu Zhao,Jing Zhong,Weiqiu Huang,Ruoyu Chen
Hierarchical N-doped carbon nanotubes (NCTs) with controllable aspect ratios were developed for CO 2 adsorption. In this work, NCTs were synthesized by coating different amounts of 3-aminophenol/formaldehyde resin (APF) on the outer layer of silica nanotubes, carbonizing in N 2 at 700 ∘ C and removing the silica and Ni template by hydrofluoric acid etching. The obtained NCTs were activated by K 2 CO 3 . After activation, micropores on the activated N-doped carbon nanotubes (ANCTs) were enriched, the micro-surface area and pore volume of ANCT-1.0 reached 1195 m 2 g − 1 and 0.45 cm 3 g − 1 , respectively, and the corresponding adsorption capacity increased by 50% (4.50 mmol g − 1 at 0 ∘ C and 1 bar). Moreover, ANCT-1.0 maintained a high stability throughout consecutive adsorption–desorption cycles. The advantages of hierarchical N-doped carbon nanotubes, including their meso–microporous structures, high geometric aspect ratio and good stability, make them valuable and promising materials to capture carbon dioxide.
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高影响因子
Science China-Chemistry
·
2019
·Vol. 62
·期 12
·1710-1719
·
IF 6.085
Wang Guishuo,Luo Ran,Yang Chengsheng,Song Jimin,Xiong Chuanye,Tian Hao,Zhao Zhi-Jian,Mu Rentao,Gong Jinlong
Metal oxide-promoted Rh-based catalysts have been widely used for CO 2 hydrogenation, especially for the ethanol synthesis. However, this reaction usually suffers low CO 2 conversion and alcohols selectivity due to the formation of byproducts methane and CO. This paper describes an efficient vanadium oxide promoted Rh-based catalysts confined in mesopore MCM-41. The Rh-0.3VO x /MCM-41 catalyst shows superior conversion (~12%) and ethanol selectivity (~24%) for CO 2 hydrogenation. The promoting effect can be attributed to the synergism of high Rh dispersion by the confinement effect of MCM-41 and the formation of VO x -Rh interface sites. Experimental and theoretical results indicate the formation of til-CO at VO x -Rh interface sites is easily dissociated into *CH x , and then *CH x can be inserted by CO to form CH 3 CO*, followed by CH 3 CO* hydrogenation to ethanol.
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JOURNAL OF ORGANIC CHEMISTRY
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2023
·
IF 3.6
Yunying Yan,Jianjun Hao,Fenfen Xie,Fen Han,Linhai Jing,Pan Han
Magnesium-mediated reductive carboxylation of p-QMs with CO2 via an Umpolung strategy has been developed, which can be used for the preparation of various aryl acetic acids. This protocol featured high atom economy, mild conditions, and operational simplicity. The creation of this Umpolung carboxylation of p-QMs will unprecedentedly extend the application of p-QMs to nucleophilic reagents.
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PubMed
高影响因子
LETTERS IN ORGANIC CHEMISTRY
·
2023
·Vol. 20
·期 4
·370-375
·
IF 0.8
Chai Mengliang,Wu Fengtian,Wu Ling
The process of hydrogen bond donor accelerating the cycloaddition of epoxides with CO2 is green access to high economic value cyclocarbonate derivatives. However, hydrogen bond donor still has certain limitations such as poor biocompatibility and narrow substrate
scope. Our group found that folic acid could promote the coupling reaction of epoxides and CO2 through hydrogen-bonding. The reaction was used to synthesize various cyclocarbonate derivatives in good to high yields with the aid of folic acid and TBAB. In addition, benzoic
acids and 2,4-quinazoline dione were synthesized in the presence of CuCl2/folic acid and PdCl2/folic acid, respectively. The reaction mechanism was proposed based on previous reports and control experiments.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2017
·Vol. 28
·期 24
·18735-18744
·
IF 2.019
Zhang Wei,Wu Weihong,Qu Hongqiang,Xu Jianzhong,Ye Leilei,Li Baoming
In this paper, a facile method was introduced to prepare the hierarchical composite that the aligned Co 2+ doped PANI nanowires and twining Co 2+ doped PANI nanofibers were delicately synthesized on the graphite fiber (Co 2+ doped PANI/gf). The structure of Co 2+ doped PANI was confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron survey. The scanning electron microscopy showed that the surface morphology of Co 2+ doped PANI/gf could be controlled by adjusting the molar ratio of An/Co 2+ and the aniline concentration. The Co 2+ doped PANI/gf hierarchical composite exhibited a high specific capacitance of 562 F/g at 0.2 A/g and presented excellent cycling durability that it retained 92.9% of the initial specific capacitance after 1000 cycles at a scan rate of 100 mV/s. The improved electrochemical performance suggested a promising application of the Co 2+ doped PANI/gf hierarchical composite in high performance supercapacitor.
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ELECTROCHIMICA ACTA
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2018
·
IF 5.116
Cheng Cai,Yang-Fan Xu,Hong-Yan Chen,Xu-Dong Wang,Dai-Bin Kuang
Photoelectrochemical (PEC) cell is a meaningful way to fulfil carbon dioxide (CO 2 ) conversion to value-added chemicals, but the exploration of ideal photocathode materials with high photo-conversion efficiency remains a challenge. Herein, porous ZnO@ZnSe core/shell nanosheet array on fluorine doped-tin oxide (FTO) glass is synthesized via dissolution-recrystallization mechanism by using ZnO nanosheet array as the template, and is used for the first time as the photocathode for PEC reduction of CO 2 . The effect of ZnSe loading amount on PEC responses of composite electrode is investigated in detail. Under the irradiation of visible light, the optimized ZnO@ZnSe photocathode exhibits onset potentials at 0.39 V ( vs. RHE) in CO 2 -purged 0.5 M NaHCO 3 solution and achieves the photocurrent of 1.17 mA cm -2 at −0.11 V ( vs. RHE). Interestingly, the competitive H 2 evolution reaction can be suppressed effectively and thereby the selectivity for CO 2 reduction reactions especially for CO formation is increased when the applied voltage became more negative. The faradic efficiency of CO increases dramatically from 4.2% at 0.2 V to 52.9% at −0.4 V and the electron selectivity for CO 2 reduction increases from 70.1% to 96.6% accordingly. These results demonstrate that ZnO@ZnSe composite electrode can work as promising photocathode for efficient CO 2 reduction.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2016
·
IF 2.76
Honghong Li,Qian Li,Jingcheng Hao,Zhenghe Xu,Dejun Sun
We prepared a CO 2 responsive emulsion by using switchable hydrophobic tertiary amine, N , N -dimethylcyclohexylamine (DMCHA). DMCHA exhibits little miscibility with water in the absence of CO 2 , but shows a complete miscibility with water in the presence of CO 2 . DMCHA converts to water-soluble bicarbonate salts upon treatment with CO 2 , which could induce the ionic strength increase of aqueous phase. Together with paraffin oil, DMCHA was used to prepare CO 2 responsive O/W emulsions with a conventional surfactant, sodium dodecyl benzene sulfonate (SDBS), as the emulsifier. Emulsions containing DMCHA in paraffin oil were more stable than those without DMCHA, as a result of electrostatic interactions between a small fraction of protonated DMCHA and SDBS, confirmed by surface tension and 1 H NMR measurements. However, when exposed to CO 2 most of the paraffin oil and water separate from the emulsion with formation of a middle phase microemulsion. More significantly, DMCHA could be separated from the lower water phase upon removal of CO 2 and recycled.
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Yanzi Wang,Yongzhen Chen,Caihong Wang,Jing Sun,Zhiping Zhao,Wenfang Liu
Enzymatic CO2 reduction can provide value-added chemicals from greenhouse gases at ambient temperature and pressure. However, poor solubility of CO2 results in a low conversion rate. In this work, polyethylenimine (PEI) was attached onto the surface of poly(acrylic acid)-grafted (PAA-grafted) polyethylene membranes, and then, the membranes were used in an integrated process of CO2 capture and in situ hydrogenation. Modification conditions were optimized with a surface amino group density of PEI-modified membranes as the characteristic parameter, and then, SEM, FTIR, and XPS analyses were conducted. The effect of PEI-modified membranes on enzyme-catalyzed CO2 conversion to formic acid, regeneration conditions, and reusability were studied. The results show that when the grafting ratio of PAA increased, surface amino group density of PEI-modified membranes increased up to 6.00 × 10–7 mol/cm2 and then kept constant. The optimum modification time, temperature, and PEI concentration were 40 min, 40 °C, and 0.3 wt %. With the same concentration, PEI-1800 could bring more amino groups than PEI-600. SEM, FTIR, and XPS results further confirmed PEI attachment. Introduction of membrane-supported PEI with 5.86 × 10–6 mol of amino groups facilitated greatly enzymatic CO2 hydrogenation, and the initial reaction rate increased from 0.280 to 6.90 μM/min. After being regenerated in ammonia, PEI-modified membranes could be reused, and the relative reaction rate was, respectively, 88.0% and 65.7% after 5 and 10 cycles.
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CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Xia Wang,Wulan Zeng,Mingjun Song,Fengli Wang,Xiude Hu,Qingjie Guo,Yongzhuo Liu
To accomplish efficient CO 2 capture from coal-fired power plants, the polyetheramine of poly(propylene glycol)bis(2-aminopropyl ether) (A), with high electron cloud density, was codispersed with tetraethylenepentamine (TEPA) to prepare solid amine sorbents. The effects of the mass ratio of TEPA to A and adsorption temperature, as well as CO 2 adsorption isotherms, were investigated. The regeneration, adsorption and desorption kinetics for TEPA-functionalized MCM-41 before and after A codispersion were also studied. A improved the adsorption performance of TEPA-functionalized MCM-41 not only at 60 °C, but also at lower temperatures. When the mass ratio of TEPA to A was 50% to 10%, the breakthrough time and equilibrium adsorption capacity were 14 min and 3.58 mmol/g, respectively, at 30 °C, and 12 min and 3.09 mmol/g, respectively, at 60 °C, values that are significantly better than the values for TEPA-functionalized MCM-41. The adsorption heat of co-functionalized MCM-41 was approximately 11–13 kJ/mol in the temperature range of 30–50 °C, showing a typical physisorption characteristic. In addition, CO 2 -TPD results indicated that co-functionalized sorbent showed faster desorption rate and lower regeneration energy consumption. After ten regenerations, the equilibrium adsorption capacity was 2.93 mmol/g, representing 94.8% of the fresh sorbent capacity.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2018
·
IF 3.141
Shu Panxiang Chen,Xiaoyu Sun,Xiao Luo,Zhiwu Liang
In this study, Li/Al hydrotalcite (HT) was treated with calcination and potassium hydroxyl-ethanol to form bcHT (basic-modified calcined hydrotalcite). This material was then polyethylenimine (PEI)-functionalized to create a new sorbent that has ultralow energy consumption. Various methods were applied to characterize the sorbent, including N2 adsorption–desorption, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. CO2 adsorption capacity, which was affected by PEI loadings and adsorption temperatures, was assessed with the CO2 adsorption isotherms and cyclic CO2 adsorption–desorption performance. Results showed that the optimal CO2 adsorption capacity of 1.723 mmol/g was reached when operating with temperature of 323 K and PEI loading of 40%. The Freundlich model was applied to provide optimal correlations with the experimental data, and the correlation coefficients reached 0.997. The average isosteric heat of CO2 adsorption was calculated to be 67.492 kJ/mol. The relatively low desorption energy consumption was calculated to be 63.20 kJ/mol with the Amenomiya equation. Four kinetic models were applied to analyze the kinetics of PEI-functionalized bcHT, and both the Avrami’s fractional order model and DEM model were well fitted to the experimental data. The activation energy of the bcHT-PEI-40% was 30.34 kJ/mol calculated by the Avrami’s fractional order model, which is obviously lower than the values of the CO2 adsorption with traditional amine solution.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Rongrong Cui,Qi Shen,Chenyan Guo,Bo Tang,Nianjun Yang,Guohua Zhao
Syngas has been synthesized via (photo) electrochemical CO 2 reduction. Its amount and yield efficiency are determined the utilizable CO 2 . Here we show syngas electrosynthesis using self-supplied CO 2 , namely in situ generated CO 2 from photoelectrocatalytic pollutant oxidation. In a single-chamber based two-electrode system, CO 2 is produced continuously during photoelectrocatalytic phenol oxidization on the anode of TiO 2 nanotubes decorated with Pd nanoparticles. Such in-situ generated CO 2 is then reduced into CO at a Pd-Cu cathode. With a phenol oxidation efficiency of 87% and a faradaic efficiency of 75%, the syngas yield is as high as 339.3 μmol. The ratio of carbon-to-hydrogen in syngas is variable from 0 to 1:10 under different current densities. The reactions for syngas generation are investigated using in-situ electrochemical infrared technique and confirmed to be C 6 H 5 OH→CO 2 →CO 2 *→COOH*→CO*+H + →CO+H 2 . This study thus provides an approach to degrade pollutants and simultaneously utilize produced CO 2 for the production of value-added chemicals like syngas.
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