Nanoscale
·
2017
·Vol. 9
·期 44
·17593-17600
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IF 7.367
Min Wang,Xiangqian Fan,Lingxia Zhang,Jianjun Liu,Beizhou Wang,Ruolin Cheng,Mengli Li,Jianjian Tian,Jianlin Shi
Porous activated carbons (PACs) are promising candidates to capture CO2 through physical adsorption because of their chemical stability, easy-synthesis, cost-effectiveness and good recyclability. However, their low CO2 adsorption capacity, especially low CO2/N2 selectivity, has limited their practical applications. In this work, an optimized PAC with a large specific surface area, a small micropore size, and a large micropore volume has been synthesized by one-step carbonization/activation of casein using K2CO3 as a mild activation agent. It showed a remarkably enhanced CO2 adsorption capacity as high as 5.78 mmol g−1 and an excellent CO2/N2 selectivity of 144 (25 °C, 1 bar). Based on DFT calculations and experimental results, the coexistence of adjacent pyridinic N and –OH/–NH2 species was proposed for the first time to make an important contribution to the ultra-high CO2 adsorption performance, especially CO2/N2 selectivity. This work provides effective guidance to design PAC adsorbents with high CO2 adsorption performance. The content of pyridine N combined with –OH/–NH2 was further elevated by additional nitrogen introduction, resulting in a further enhanced CO2 adsorption capacity up to 5.96 mmol g−1 (25 °C, 1 bar). All these results suggest that, in addition to the well-defined pore structure, pyridinic N with neighboring OH or NH2 species played an important role in enhancing the CO2 adsorption performance of PACs, thus providing effective guidance for the rational design of CO2 adsorbents.
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PubMed
高影响因子
JOURNAL OF POWER SOURCES
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2017
·
IF 6.395
Jin Li,Qian Zhang,Peng Qiu,Lichao Jia,Bo Chi,Jian Pu,Jian Li
La 2 NiO 4+δ (LN)-coated PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ (PBSCF) composite cathode, designated as PBSCF-LN, for the intermediate temperature solid oxide fuel cells (IT-SOFCs) is prepared by solution infiltration , and investigated comparatively with single phase PBSCF cathode in the half and full cells using Ag and/or Pt paste as the current collector. Compared with Pt, Ag current collector results in a decrease of cathode polarization resistance ( R P ) by an order of magnitude, which suggests that Ag is electrocatalytically active and not suitable for the use of studying the cathode performance of IT-SOFCs. The R P value of PBSCF-LN cathode is significantly lower than that of PBSCF cathode, no matter whether Pt or Ag current collector is used for the measurement. High power densities ranging from 0.24 to 0.94 W cm −2 at temperatures between 600 and 750 °C are achieved using a full cell with PBSCF-LN cathode. Upon exposure to a CO 2 -rich atmosphere, carbonate particles are formed on the surface of PBSCF cathode, causing irreversible degradation of electrochemical performance. In contrast, the surface of PBSCF-LN cathode remains clean, and its performance degradation due to CO 2 adsorption is recoverable.
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INORGANIC CHEMISTRY
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2015
·
IF 4.762
De-Yun Ma,Zhi Li,Jun-Xia Xiao,Rong Deng,Pei-Feng Lin,Rui-Qun Chen,Yun-Qiu Liang,Hai-Fu Guo,Bei Liu,Jian-Qiang Liu
By using a strategy of introducing hydrophobic groups to the linkers, a hydrostable MOF was constructed based on 5-nitroisophthalate and 2,2′-dimethyl-4,4′-bipyridine coligands, revealing a 3D dia topology structure with a 1D channel parallel to the c axis. TGA, PXRD, and water vapor sorption results show high thermal and water stability for the framework. The framework is very porous and possesses not only high busulfan payloads with an encapsulation efficiency up to 21.5% (17.2 wt %) but also very high CO2 selective capture compared with that of other small gases (i.e., CH4, N2, O2, CO, and H2) at 298 K based on molecular simulations due to the pore surface being populated by methyl and nitryl groups. Furthermore, in vitro MTT assays were conducted on four different cells lines with increasing concentrations of the framework, and the results showed that the framework was nontoxic (cell viability >80%) in spite of the concentrations up to 500 μg/mL.
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PubMed
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RSC Advances
·
2015
·Vol. 5
·期 70
·56478-56485
·
IF 3.84
Guozhi Fan,Shanshan Luo,Qiang Wu,Tao Fang,Jianfen Li,Guangsen Song
A magnetic Fe3O4@SiO2–ZnBr2 catalyst was prepared by supporting ZnBr2 on silica-coated magnetic nanoparticles of Fe3O4 and used as a recoverable catalyst for the direct synthesis of diphenyl carbonate (DPC) from CO2 and phenol in the presence of carbon tetrachloride. The as-prepared catalyst was characterized by infrared spectroscopy (IR), powder X-ray diffraction (XRD), a X-ray photoelectron spectrometer (XPS) and BET. Zn loading in the supported catalyst and leaching during the reaction process were determined by atomic absorption spectroscopy (AAS). It was found that Fe3O4@SiO2–ZnBr2 showed higher catalytic activity than homogenous ZnCl2 and ZnI2 as well as homogenous ZnBr2. With this new catalyst under optimized conditions, a yield of DPC at 28.1% was obtained. The heterogeneous catalyst Fe3O4@SiO2–ZnBr2 can also be recovered by a permanent magnet after the reaction and reused up to 4 times without noticeable deactivation.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2012
·
IF 2.237
Fang-fang Tong,Hong Xu,Jian Yu,Li-xiong Wen,Jun Zhang,Jia-song He
A series of poly(methyl methacrylate) (PMMA)/1-dodecyl-3-methylimidazolium hexafluorophosphate ionic liquid ([C12MIM][PF6]) blends were prepared by melt blending. The compatibility of blends was verified by scanning electron microscopy and differential scanning calorimetry. The introduction of [C12MIM][PF6] decreased the glass transition temperature of the blends due to its plasticization effect and increased the diffusivity of CO2 without significantly affecting the CO2 solubility. These blends were foamed with supercritical CO2 as the blowing agent via a pressure-quenching process. The foaming conditions are divided into three regions according to the main morphological difference of foams. At relatively low temperatures and pressures, neat PMMA could not be foamed, while the addition of [C12MIM][PF6] facilitated the formation of cells. By increasing temperature or pressure, neat PMMA foams were obtained with wide cell size distribution, while the blend foams were formed with narrowed cell size distribution and increased cell size. At high temperatures and pressures, neat PMMA was foamed with narrow cell size distribution and high cell density, while the major effect of [C12MIM][PF6] was to increase the cell size. These results indicated that the plasticization effect and the low surface energy of [C12MIM][PF6] accounted for the differences on the cell morphology between neat PMMA and the blend foams.
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RSC Advances
·
2015
·Vol. 5
·期 86
·70101-70108
·
IF 3.84
Qiong Wu,Jun Shi,Jing Wei,Liu Yang,Shaokui Cao
In this work, aliphatic poly(urethane-amine) (PUA) grafted mesoporous hollow hydroxyapatite (H-HAP) microparticles were prepared via in situ polymerization in supercritical CO2. Thermal-responsive PUA acted as the on–off gates inside the mesoporous H-HAP due to the stretch and shrinkage of the PUA polymer chains at different temperatures. The PUA-grafted hollow HAP (PUA-g-H-HAP) microparticles displayed high specific surface area (95 m2 g−1) and drug loading efficiency (60%). The in vitro drug release studies indicated that PUA-g-H-HAP microparticles exhibited distinguishable pH- and thermal-dependent drug release properties, and PUA on–off switches enabled the DOX release in a reversible way by simply adjusting the environmental temperature. Moreover, compared to the hollow HAP microparticles having a higher amount of released DOX over the initial 2 h (about 24.4% of total released drug over 24 h) at 37 °C and pH 7.4, PUA-g-H-HAP microparticles displayed a sustained release property with the value of only 10.7% deriving from the blockage of the stretched PUA chains inside the mesoporous H-HAP.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2015
·
IF 2.587
Song Zhao,Xiaochang Cao,Zijian Ma,Zhi Wang,Zhihua Qiao,Jixiao Wang,Shichang Wang
In this work, imidazolate framework ZIF-8 nanoparticles were synthesized and incorporated into a poly(vinylamine) (PVAm) coating solution. The chemical structure of a PVAm/ZIF-8 film was characterized by X-ray diffraction and attenuated total reflectance Fourier transform infrared spectroscopy techniques. Mixed-matrix membranes (MMMs) were developed by coating the PVAm/ZIF-8 mixed dispersion on a polysulfone (PSf) support membrane. Surface and cross-sectional scanning electron microscopy images of the MMMs were employed to observe the dispersion of nanoparticles in the polymer matrix. The CO2 permeance and CO2/N2 selectivity of the MMMs were evaluated by using a CO2/N2 mixture gas. Optimal preparation parameters for the MMMs were achieved by varying the incorporated ZIF-8 contents in the coating solution and the wet coating thickness. The effect of incorporated ZIF-8 on improving the gas permselectivity was revealed, and the mechanism of CO2-facilitated transport in the PVAm/ZIF-8/PSf membrane was analyzed. The CO2/N2 separation performance of PVAm/ZIF-8/PSf membranes with different wet coating thicknesses was also evaluated at 22–60 °C to analyze the changes of the gas permselectivity with increasing temperature.
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JOURNAL OF SUPERCRITICAL FLUIDS
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2014
·
IF 2.571
Qin-Qin Xu,Yu-Ling Ma,Gang-Xu,Jian-Zhong Yin,Ai-Qin Wang,Jin-Ji Gao
Well-defined Ag nanowires were obtained in SBA-15 at a short deposition time of 5 min in supercritical CO 2 when adding a small amount of ethylene glycol as the co-solvent. Ethylene glycol played a key role in dictating the nanowire morphology. Through detailed investigation of the whole deposition process, including the dissolution of precursor assisted by the co-solvent, the diffusion properties of the precursor into the nano-scale channels of the substrate, and the interaction between the precursor and the substrate, we found that a small amount of precursors were reduced into Ag 0 by ethylene glycol at the initial stage of the deposition. The resultant Ag 0 then acted as nuclei leading to a non-equilibrium sorption of the precursor. The rapid adsorption of the precursor onto the substrate resulted in a high loading of Ag in a short deposition time and the formation of nanowire morphology. Furthermore, this method was successfully extended to other porous substrates such as γ-Al 2 O 3 , SiO 2 and KIT-6, demonstrating its great potentials in the synthesis of nanocomposites.
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高影响因子
MATERIALS LETTERS
·
2014
·
IF 2.269
Hongxia Yang,Nan Wang,Yumei Ren,Lu Cai,Zhimin Chen,Qun Xu
Three-dimensional (3D) graphene-pyrrole/carbon nanotubes/polyaniline (GPCP) nanohybrids were successfully prepared through a facile and scalable method with the assistance of supercritical CO 2 (SC CO 2 ), which could be used as efficient electrode materials for supercapacitors . Our experimental results indicate that SC CO 2 can not only help combining multi-component nanocomposites but also improve the conductivity of the nanohybrids. The electrochemical measurements show that the specific capacitance of the as-prepared nanohybrids with the assistance of supercritical CO 2 can run up to 400 F g −1 , which verify that SC CO 2 provides an effective route to the scalable production of 3D nanohybrids for the potential application in supercapacitors.
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RSC Advances
·
2015
·Vol. 6
·期 4
·2810-2818
·
IF 3.84
Ting Zhang,Xuefeng Wang,Xueli Huang,Yinnian Liao,Jinzhu Chen
Chemical fixation of carbon dioxide (CO2) to cyclic carbonates was investigated by using bifunctional nucleophile–electrophile catalysts of a metallophthalocyanine–carbon nitride hybrid [MPc/g-C3N4 (M = Co, Cu)] in the absence of any co-catalysts and organic solvents. MPc/g-C3N4 was readily obtained by direct calcination of a mixture of dicyandiamide and metallophthalocyanine under a flowing-nitrogen atmosphere, and the MPc/g-C3N4 prepared at 480 °C (MPc/g-C3N4-480) showed the highest catalytic performance toward the cycloaddition reaction of CO2 to epichlorohydrin (ECH). For bifunctional MPc/g-C3N4, the MPc species function as Lewis acidic centers for ECH activation via electrophilic attack; while, the g-C3N4 moiety, possessing abundant and uncondensed species with the forms of primary amine (NH2) groups and secondary amine (C–NH–C) groups at the edges of graphitic sheets as edge defects, acts as an organic base for CO2 activation through nucleophilic attack. The developed MPc/g-C3N4 is stable and insoluble in any commonly used organic solvents and behaves as heterogeneous catalyst, leading to facile separation and recycling in a CO2 fixation reaction.
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CATALYSIS LETTERS
·
2017
·Vol. 147
·期 7
·1654-1664
·
IF 2.799
Xu Fei,Cheng Weiguo,Yao Xiaoqian,Sun Jian,Sun Wei,Zhang Suojiang
Abstract A series of thiourea-based ionic liquids (TBILs) were developed as efficient catalysts for the synthesis of cyclic carbonates by the cycloaddition of CO 2 with epoxides under metal-, cocatalyst- and solvent-free conditions. Different substituted groups including electron donating and withdrawing groups were introduced onto the para-position of the aromatic ring in cation of TBILs. The effect of the catalyst structures on the reaction activity was systematically investigated. Among the ionic liquids, TBIL3 with substituted OCH 3 group showed the best performance with 99% propylene oxide conversion as well as 99% propylene carbonate selectivity under mild conditions (1.5 MPa, 130 °C and 3 h) without any co-solvent. It was demonstrated that two secondary amine groups of the thiourea unit could dually activate the epoxides and CO 2 and have a synergetic effect with the halide anion. Graphical Abstract
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2017
·
IF 9.446
Jibo Liu,Huijie Shi,Qi Shen,Chenyan Guo,Guohua Zhao
Aiming at improving the efficiency of photoelectrocatalytic (PEC) CO 2 conversion to methanol, a heterogeneous photoelectrocatalyst was prepared by covalently binding a Ru(II) metal-organic complex (Ru-Py) containing exposed pyridyl on the periodic TiO 2 nanotube arrays (TNTAs). PEC characterization indicated that the Ru-Py/TNTAs photocathode exhibited excellent PEC CO 2 reduction activity in aqueous solution. The initial CO 2 reduction potential on Ru-Py/TNTAs photocathode reached −0.4 V (vs. NHE) under simulated solar irradiation. The cathodic photocurrent response of Ru-Py/TNTAs in CO 2 -satuarated aqueous solution was about 1.79 mAcm −2 , which was 2.4 times that of TNTAs . It may be caused by the enhanced light absorption in the visible region originated from Ru-Py. Meanwhile, Ru-Py played an important role in accelerating the separation of photoinduced electron-hole pairs evidenced by the photoluminescence spectra. PEC CO 2 reduction test showed that 84.8 μmol methanol was produced with 63.9% faraday efficiency, 62.6 turnover number (TON) and 45% selectivity at −0.9 V under 8 h irradiation. Furthermore, the non-covalent bonded system only produced 41.3 μmol methanol indicating that the carboxylic covalent linking displayed excellent electron transfer efficiency and methanolization performance. The mechanism investigation revealed that the exposed pyridyl provided the active sites in forming pyridiniumformate intermediates confirmed by the differential UV–vis absorption ( ΔA ) spectrum, which was of great significance in the efficient CO 2 methanolization. The probable reaction pathway for catalytic CO 2 reduction to methanol was also proposed combining the possible intermediates detected by gas chromatography mass spectrometry (GCMS).
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