RSC Advances
·
2016
·Vol. 6
·期 69
·65282-65290
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IF 3.289
Dongdong Peng,Ye Liu,Shaofei Wang,Zhizhang Tian,Qingping Xin,Hong Wu,Jianfeng Chen,Zhongyi Jiang
Facilitated transport membranes by utilizing π complexation reactions between metal ions and penetrants have been actively explored, however, the different facilitated transport abilities of metal ions remains to be disclosed. In this study, poly(N-vinylimidazole) coated carbon nanotube particles (PVI@CNT) were prepared via precipitation polymerization of N-vinylimidazole monomers on a CNT surface. The PVI@CNT particles were then loaded with four kinds of divalent metal ions, Cu2+, Fe2+, Ca2+ and Mg2+, and incorporated into polyimide (PI) to prepare M2+–PVI@CNT hybrid membranes. The structure of M2+–PVI@CNT particles and PI–M2+–PVI@CNT membranes was analyzed by different characterization tools. Taking CO2/CH4 as the model separation system, the hybrid membranes containing Cu2+ and Fe2+ at filler content of 7 wt% showed the maximum increase of CO2 permeability of 89% and 87% compared with those of a pristine PI membrane. Meanwhile, the selectivity of these membranes shows little increase. However, membranes containing Ca2+ and Mg2+ show only little enhancement in the separation properties. Such results can be interpreted based on the π complexation mechanism, transition metal ions Cu2+ and Fe2+ possess a strong CO2 facilitated transport ability whereas main-group metal ions Ca2+ and Mg2+ possess a weak facilitated transport ability. Finally, a correlation of the electronegativity of metal ions with their CO2 facilitated transport abilities was explored.
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RSC Advances
·
2017
·Vol. 7
·期 78
·49777-49786
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IF 3.108
Zanru Guo,Hongjian Gu,Wei Ma,Qiang Chen,Zhanfeng He,Jiali Zhang,Yongxin Liu,Longzhen Zheng,Yujun Feng
The design of controllable or “signal-triggered” metal nanoparticles is one of the emerging trends in nanotechnology and advanced materials. CO2-switchable polymer-hybrid silver nanoparticles (AgNPs) were prepared by a one-pot reaction reducing AgNO3 and trithioester terminated PDEAEMA with sodium borohydride (NaBH4). The hybrids showed a long-term stability, and their size and size distribution can be easily modulated by tuning the molar ratio of polymers to AgNO3. The hybrids not only exhibit hydrophobic–hydrophilic transitions in immiscible mixed solvents, but also undergo a switchable dispersion/aggregation states upon alternately treating with CO2 and N2. Moreover, this smart hybrid was preliminarily used as catalyst for the reduction of 4-nitrophenol. The catalytic activity of the hybrids can be switched and monotonously tuned by varying the flow rate of CO2 purged into the reaction system, which may open a new avenue for tailoring the catalytic activity of metal nanoparticles toward a given reaction.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2017
·
IF 3.615
Xingzhong Guo,Li Ding,Kazuyoshi Kanamori,Kazuki Nakanishi,Hui Yang
A novel CO 2 sorbent was prepared by modifying polyethyleneimine (PEI) on hierarchically porous silica (HPS) monoliths with well-defined macro-mesopores through wet impregnation method. HPS monoliths before and after functionalization were characterized by scanning electron microscopy (SEM), differential thermal analysis/thermogravimetry (DTA/TG), fourier transform infrared spectroscopy (FT-IR) and nitrogen adsorption/desorption analysis (BET), and the CO 2 adsorption-regeneration properties of as-synthesized sorbents were investigated by thermogravimetric analysis (TG). The effects of loaded PEI amount as well as adsorption temperature and CO 2 partial pressure on the CO 2 adsorption performance of the as-prepared sorbents were also studied. The results showed that the porous structure of HPS-PEI sorbents was preserved after functionalization, while the specific surface area and pore volume decreased with increasing amount of amines to some extent. The use of PEI had a remarkable improvement on the CO 2 adsorption capacity. With the increasing amount of PEI loaded, the CO 2 adsorption capacity improved significantly. The highest CO 2 adsorption capacity of 2.44 mmol (g sorbent) −1 was obtained at 75 °C in the CO 2 partial pressure of 100 kPa for the HPS loaded with 60 wt% PEI. Adsorption/desorption cycles indicated that the PEI-modified HPS sorbents had a good stability and regeneration.
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ENERGY
·
2016
·
IF 4.292
Xiao Cheng,Rong Chen,Xun Zhu,Qiang Liao,Liang An,Dingding Ye,Xuefeng He,Shuzhe Li,Lin Li
The development of highly efficient photocatalytic reactor is of importance to improve the performance of the photocatalytic reduction of CO 2 . In this work, an optofluidic planar microreactor is designed and fabricated for the photocatalytic reduction of CO 2 with liquid water in alkaline environment . Such design offers several advantages of large surface-area-to-volume ratio, enhanced mass and photon transfer and more uniform light distribution. The performance of the developed planar microreactor is evaluated by measuring the methanol concentration to estimate the methanol yield under various operating parameters, including the liquid flow rate , light intensity, catalyst loading and NaOH concentration. It is shown that increasing the liquid flow rate firstly improves and then decreases the methanol concentration while the methanol yield continuously increases as the liquid flow rate increases. The increase of the light intensity and NaOH concentration increases both the methanol concentration and yield. Increasing the catalyst loading firstly improves the performance and then results in the reduction of the performance. A maximum methanol yield of 454.6 μmole/g-cat·h is achieved under a liquid flow rate of 50 μL/min, 0.2 M NaOH, and the light intensity of 8 mW/cm 2 .
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JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Yang Li,Dario R. Dekel,Xuezhong He
Amine-rich facilitated transport membranes (FTMs) attract great interest in intensifying the membrane-based CO 2 separation processes. The high-molecular-weight polyvinylamine (PVAm) polymers containing fixed-site carriers of the amino groups were used to prepare highly CO 2 -permeable membranes. The sterically hindered PVAm polymers of poly(N-methyl-N-vinylamine) and poly(N-isopropyl-N-vinylamine) were obtained by functionalization of PVAm to provide superior CO 2 solubility. By loading the mobile carriers of amino acid salt (AAS) and CO 2 -philic graphene oxide (GO), the prepared FTMs render enhanced CO 2 permeance and CO 2 /N 2 selectivity. The d-spacing of 8.8 Å and the ultramicropores of 3.5 Å from GO nanosheets provide the combination of both selective surface flow and molecular sieving mechanisms to achieve improved CO 2 permeance and CO 2 /N 2 selectivity. In addition, the intercalation of GO hinders N 2 transport through the membrane due to a longer pathway, while the mobile carriers of AAS introduced into the PVAm matrix facilitate CO 2 transport through the selective layer. Therefore, the CO 2 /N 2 selectivity of the prepared FTMs was significantly enhanced to 171 based on the intensified carrier-driving transport mechanism. It can be concluded that amine-rich membranes based on both fixed and mobile carriers of the amino groups together with intercalated GO can synergistically improve the CO 2 /N 2 separation performance, and be potentially applied for CO 2 capture from flue gas .
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Tongjun Yang,Junpeng Xu,Hailiang Sheng,Junqin Wang,Gang Hu,Songmiao Liang,Lijie Hu,Lihua Zhang,Haibo Xie
The CO 2 -based reversible ionic liquid solution of 1,1,3,3-tetramethylguanidine (TMG) and ethylene glycol (EG) in dimethyl sulfoxide (DMSO) after capturing CO 2 , (2[TMGH] + [O 2 COCH 2 CH 2 OCO 2 ] 2− /DMSO ( χ RILs = 0.1), provides a sustainable and effective platform for cellulose dissolution and homogeneous utilization. Highly porous cellulose aerogel beads and monoliths were successfully prepared via a sol-gel process by extruding cellulose solution into different coagulation baths (NaOH aqueous solution or alcohols) and exposing the cellulose solution in open environment, respectively, and followed by different drying techniques, including supercritical CO 2 -drying, freeze-drying and air-drying. The effect of the coagulation baths and drying protocols on the multi-scale structure of the as-prepared cellulose aerogel beads and monoliths were studied in detail, and the sol-gel transition mechanism was also studied by the solvatochromic parameters determination. High specific surface area of 252 and 207 m 2 /g for aerogel beads and monoliths were achieved, respectively. The potential of cellulose aerogels in dye adsorption was demonstrated.
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PubMed
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 5
·1006
·
IF 4.2
Xia Wang,Wulan Zeng,Peidan Hu,Shengxin Liu,Yuechao Lin,Zhaowen He,Chunling Xin,Xiangjun Kong,Jinghan Xu
Organic amine-modified mesoporous carriers are considered potential CO2sorbents, in which the CO2adsorption performance was limited by the agglomeration and volatility of liquid amines. In this study, four additives of ether compounds were separately coimpregnated with polyethylene polyamine (PEPA) into MCM-41 to prepare the composite chemisorbents for CO2adsorption. The textural pore properties, surface functional groups and elemental contents of N for MCM-41 before and after functionalization were characterized; the effects of the type and amount of additives, adsorption temperature and influent velocity on CO2adsorption were investigated; the amine efficiency was calculated; and the adsorption kinetics and regeneration for the optimized sorbent were studied. For 40 wt.% PEPA-loaded MCM-41, the CO2adsorption capacity and amine efficiency at 60 °C were 1.34 mmol/g and 0.18 mol CO2/mol N, when the influent velocity of the simulated flue gas was 30 mL/min, which reached 1.81 mmol/g and 0.23 mol CO2/mol N after coimpregnating 10 wt.% of 2-propoxyethanol (1E). The maximum adsorption capacity of 2.16 mmol/g appeared when the influent velocity of the simulated flue gas was 20 mL/min. In addition, the additive of 1E improved the regeneration and kinetics of PEPA-loaded MCM-41, and the CO2adsorption process showed multiple adsorption routes.
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ChemSusChem
·
2024
·
IF 7.5
Rui Yang,Xiaozhong Zheng,Hao Fu,Xinyue Cao,Yangguang Hu,Yiyin Huang
Graphical Cu 7 S 4 /Cu nanoflowers with strong CO 2 adsorption and abundant boundaries were developed by a facile thermal reduction, which underwent in situ dynamic restructuring during ECR to generate highly active S-doped Cu 2 O/Cu hybrid catalyst. Thermodynamic and experimental analysis revealed that the optimized adsorption of the HCOO * intermediate on S−Cu 2 O/Cu was regulated and surface H was suppressed by S-doping. The high activity for CO 2 -to-HCOOH attributed to the strengthen CO 2 adsorption, abundant boundaries at Cu 2 O/Cu interfaces, and the regulation of adsorption energy by S-doping Optimized catalytic properties and reactant adsorption energy played a crucial role in promoting CO 2 electrocatalysis. Herein, Cu 7 S 4 /Cu underwent in situ dynamic restructuring to generate S−Cu 2 O/Cu hybrid catalyst for effective electrochemical CO 2 reduction to formate that outperformed Cu 2 O/Cu and Cu 7 S 4 . Thermodynamic and in situ Raman spectra revealed that the optimized adsorption of the HCOO* intermediate on S−Cu 2 O/Cu was regulated and the H 2 pathway (surface H) was suppressed by S-doping. Meanwhile, Cu 7 S 4 /Cu nanoflowers created abundant boundaries for ECR and strengthened the CO 2 adsorption by inducing Cu. These findings provide a new perspective on synthetic methods for various electrocatalytic reduction processes.
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Nature Communications
·
2024
·Vol. 15
·期 1
·1-12
·
IF 14.7
Ren Yuqi,Fu Yiwei,Li Naixu,You Changjun,Huang Jie,Huang Kai,Sun Zhenkun,Zhou Jiancheng,Si Yitao,Zhu Yuanhao,Chen Wenshuai,Duan Lunbo,Liu Maochang
H 2 O dissociation plays a crucial role in solar-driven catalytic CO 2 methanation, demanding high temperature even for solar-to-chemical conversion efficiencies <1% with modest product selectivity. Herein, we report an oxygen-vacancy (V o ) rich CeO 2 catalyst with single-atom Ni anchored around its surface V o sites by replacing Ce atoms to promote H 2 O dissociation and achieve effective photothermal CO 2 reduction under concentrated light irradiation. The high photon flux reduces the apparent activation energy for CH 4 production and prevents V o from depletion. The defects coordinated with single-atom Ni, significantly promote the capture of charges and local phonons at the Ni d -impurity orbitals, thereby inducing more effective H 2 O activation. The catalyst presents a CH 4 yield of 192.75 µmol/cm 2 /h, with a solar-to-chemical efficiency of 1.14% and a selectivity ~100%. The mechanistic insights uncovered in this study should help further the development of H 2 O-activating catalysts for CO 2 reduction and thereby expedite the practical utilization of solar-to-chemical technologies.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Lixin Song,Guobin Liu,Zhenping Qu
CO 2 hydrogenation to methanol and/or dimethyl ether (DME) holds promise for mitigating greenhouse gas effects and addressing energy scarcity. However, the relationship between product selectivity and the collective nature of the catalysts remains ambiguous due to the intricate reaction network. Here, a series of Cu/Zn x Al y O z catalysts with different surface properties have been engineered by manipulating the Zn/Al ratio to achieve product controllability for CO 2 hydrogenation. The results unveil the pivotal role of the H 2 dissociation capability in governing CO 2 conversion, which is regulated by the concentration of Cu 0 species. Furthermore, the number of surface hydroxyl groups, the proportion of moderately strong basic sites and moderately strong acidic sites show desirable linear correlations with the selectivity of CO, CH 3 OH, and DME, respectively. Importantly, the ZnAl 2 O 4 -Al 2 O 3 or Cu-ZnAl 2 O 4 -Al 2 O 3 interface notably enhances moderately strong acidic sites, aiding methanol dehydration to DME. This work offers a comprehensive guide to the rational design of catalysts for oriented product synthesis from CO 2 hydrogenation.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Furong Li,Gonghe Tong,Yanbin Li,Zhigang Wang,Xiaoyao Tan
Protonic ceramic electrochemical reactors (PCER), having the advantages of high efficiency, adjustability, and scalability, exhibit great potential in energy storage such as conversion of CO 2 into high-value chemicals. Designing critical components like the electrolyte and electrodes of electrochemical reactors is essential to widen commercial applications. The present work constructed a three-layer microtubular PCER (MT-PCER) for CO 2 hydrogenation. BaCe 0.5 Zr 0.3 Y 0.2 O 3-δ (BCZY) was used as the electrolyte material to prepare BCZY/Ni-BCZY/Ni triple-layer hollow fibers (TLHFs) by a phase-inversion based co-spinning/co-sintering process. Porous Ni-BCZY was the catalytic functional (cathode) layer, and the metallic Ni composed the current collector layer. Results indicated that CO 2 conversion and CH 4 selectivity were significantly enhanced when the NiO content in the cathode layer increased from 40 % to 60 %, while there was no significant change for the content continuously increasing to 80 %. Compared with the reactor employing dual-layer hollow fibers, the Ni collector layer in TLHFs presented a remarkable intensification of the methanation performance. As a result, the MT-PCER with 60 % NiO content in the cathode layer and utilizing the Ni current collector was the recommended reactor structure, which possessed the CO 2 conversion of 29.8 %, CH 4 selectivity of 50.9 %, CH 4 yield of 15.2 %, and faradaic efficiency of 43.6 % at 700 °C and 2 V applied voltage. The adjusted design of the TLHF facilitated the advancement of the performance and efficacy of the MT-PCER, promoting carbon capture, utilization, and storage processes.
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JOURNAL OF MOLECULAR LIQUIDS
·
2024
·
IF 5.3
Xiaoyan Pei,Wangyue Song,Yunlei Shi,Yang Zhao,Zhiyong Li
Pickering emulsions with a stimulus response have been paid extensive concern due to their long-term stability and demulsification on-command. Metal-organic frameworks (MOFs) are expectable emulsifying agents to build Pickering emulsions based on their excellent properties such as high specific surface area, adjustable porosity and pore size. Herein, a novel kind of CO 2 -triggered Pickering emulsions formed by (3-aminopropyl)triethoxysilane (APTES)-functionalized M-MOF-74 (M-MOF-74-APTES, M = Zn, Cu or Mg) has been developed for the first time. It was found that even at the M-MOF-74-APTES amount of 0.5 wt%, the functionalized MOFs could still stabilize the n-hexane-water mixture to construct Pickering emulsions. The as-generated Pickering emulsions could be efficiently demulsified upon bubbling of CO 2 , resulting in complete separation of oil and water phases, but could be restored by subsequent N 2 bubbling under homogenization. Mechanism study indicated that the acid-base reaction of CO 2 with the amino group of M-MOF-74-APTES resulted in the creation of hydrophilic salts, which led to the lowering of particle wettability and broke the stability of the emulsion, causing demulsification of the Pickering emulsion. After removing CO 2 , the emulsion can be reconstructed by the reversible reaction. As an applied example, the Pickering emulsion has been availed as a micro-reaction system and M-MOF-74-APTES as a carrier of Pd(OAc) 2 catalyst to realize the efficient combination of Suzuki-Miyaura reaction, product isolation and reuse of catalysts via alternate bubbling or removing of CO 2 .
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