CATALYSIS TODAY
·
2019
·
IF 4.888
Lei Zhang,Hao Wang,Chengguang Yang,Xiaopeng Li,Jian Sun,Hui Wang,Peng Gao,Yuhan Sun
The present work reports on the promoting effects of rare earth elements (La, Ce and Y) to FeK/Al 2 O 3 catalysts on liquid hydrocarbons from CO 2 hydrogenation. The addition of La, Ce and Y can both improve the selectivity of C 5+ hydrocarbons and reduce the selectivity of CH 4 . The C 5+ selectivity can enhance to about 60 % with CH 4 selectivity of around 11 % at CO 2 conversions above 20 %. N 2 adsorption–desorption, in situ XRD, H 2 –TPR, CO 2 /H 2 –TPD, HRTEM and XPS are used to characterize the FeK/Al 2 O 3 and FeK/M-Al 2 O 3 (M = La, Ce, Y) catalysts. The results show that the introduction of rare earth elements into the FeK/Al 2 O 3 catalyst obviously reduces the adsorption of H 2 , which suppresses the CH 4 formation. On the other hand, rare earth elements also promote the adsorbed CO 2 species, which leads to the enhanced liquid hydrocarbons selectivity. Finally, the tailored CO 2 /H 2 ratio of CO 2 and H 2 adsorption on the catalyst surface can influence the catalyst activity and the product selectivity evidently.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Beibei Zhang,Qiongjie Yan,Gang Chen,Chunhai Yi,Suitao Qi,Bolun Yang
To date, mixed matrix membranes with nano-filler was considered to be an effective method to enhance the gas permselectivity of membrane separation. In this work, mixed matrix membranes for the facilitated transport of CO 2 were prepared. Hexafluoroisopropylidene diphthalic anhydride - based aromatic polyimide was applied as polymeric matrix, while the zinc ion functionalized titanium dioxide spherical nano-particle was selected as nano-filler. The physical property, chemical structure and membranes morphology were characterized by FT-IR, TG, XRD, SEM, CA and XPS. Gas permselectivity was investigated using binary mixture gas of CO 2 /N 2 and CO 2 /CH 4 , respectively. The effects of nano-filler content, functional group, operation temperature on gas permselectivity were studied. Results show that the incorporation of spherical nano-filler can effectively restrict the polymer chain packing and lead to low crystallinity. By incorporation of zinc ion modified spherical nano-filler, the CO 2 permeability increased about 68.7~78.7%. PI-TiO 2 -PDA-Zn 2+ mixed matrix membranes with 7.5 wt% nano-filler addition displayed the highest CO 2 permeability (145.37 Barrer for CO 2 /N 2 feed gas and 108.36 Barrer for CO 2 /CH 4 feed gas, 1 Barrer = 7.5 × 10 -18 m 2 s −1 Pa −1 ) and satisfied CO 2 /inert gas selectivity (CO 2 /N 2 selectivity of 49.28 and CO 2 / CH 4 selectivity of 49.48). CO 2 permeability increased and selectivity decreased with the elevated temperature. Besides, the membrane exhibited good stability in the 30 days testing.
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ACS Applied Energy Materials
·
2021
·
IF 6.024
Yangyang Wang,Xue Wang,Bingcheng Ge,Jianxin Guo,Carlos Fernandez,Qiuming Peng
The Li–CO2 battery is a potential energy storage device that not only possesses a theoretical energy density as high as 1876 W h kg–1 but also alleviates the consumption of fossil resources by converting the greenhouse gas CO2 into electric energy. However, some technique bottlenecks, such as high overpotential, low recyclability, and low energy density, severely prohibit its application rhythm. Here, we prepare a binder-free MXene–MnO2 composite film using vacuum-assisted filtration and in situ reduction, which can be used as a freestanding cathode for Li–CO2 batteries. This MXene–MnO2 film electrode bestows good cycle stability (∼220 cycles), high specific capacity, and lower overpotential (∼0.89 V) in Li–CO2 batteries. Both experimental tests and first-principles calculations reveal that the enhanced electrochemical properties are associated with three aspects. First, the MXene–MnO2 film offers a high electrical conductivity and porous structure, which provide fast transport channels for electrons and ions. Then, the replacement of Mn by Ti increases the adsorption of Li ions, which facilitates the rapid decomposition of Li2CO3. Finally, the synergistic effect of MXene and MnO2 exposes a large number of active sites, which increases the capacity of Li–CO2 batteries. Therefore, this self-supporting strategy on the MXene composite paves a way to develop high-performance Li–CO2 batteries.
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ENERGY & FUELS
·
2018
·
IF 3.024
Na Rao,Mei Wang,Ziming Shang,Yanwen Hou,Guozhi Fan,Jianfen Li
Modifications by impregnation and grafting are commonly used for the preparation of amine-functionalized MCM-41. A comprehensive evaluation of the advantages and disadvantages of the two methods was performed in this work. MCM-41 was synthesized by the hydrothermal method, setting the amine-loading mass fraction at 40, 50, and 60 wt %. Three amine-modified adsorbents were prepared by impregnating polyethylenimine (PEI), and the three other adsorbents were prepared by grafting 3-aminopropyltriethoxysilane (APTS) onto MCM-41. The as-prepared adsorbents were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and N2 adsorption–desorption techniques. CO2 adsorption capacities were measured, and the experimental data were fitted with adsorption kinetic models. The cyclic stability of the adsorbents prepared by the two kinds of amine-modified methods was compared using the cyclic adsorption–desorption experiments. The characterization results showed that the target adsorbents were prepared successfully. The thermal stability of the adsorbents modified by grafting was better than the thermal stability of the adsorbents modified by the impregnation. Maximum CO2 adsorption capacities of 3.53 mmol g–1 (50% PEI–MCM-41) and 2.41 mmol g–1 (50% APTS–MCM-41) could be reached at 25 °C and 1 atm, which were 4.7 and 3.2 times greater than that of MCM-41. The Avrami model fitted the experimental data well, indicating a variety of interactions between the adsorbents and CO2. CO2 adsorption capacity after 5 adsorption–desorption cycles decreased by 14.22 and 5.19% for the adsorbents prepared by impregnation and grafting, respectively. It was concluded that MCM-41 modified by impregnation and grafting followed the same kinetic model. The absorbents modified by impregnation showed higher CO2 adsorption capacity and amine-loading efficiency, while those prepared by grafting had better thermal and cyclic stabilities.
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JOURNAL OF SOLID STATE CHEMISTRY
·
2020
·
IF 2.726
Ding Guo,Cheng Li,Juan Zhang,Genyan Liu,Xiaogang Luo,Fengshou Wu
The chemical fixation of carbon dioxide to afford value added chemicals under solvent free and ambient conditions has gained considerable attentions. In this work, we successfully synthesized the porphyrin-based porous organic framework (PPOPs) through Schiff base reaction using 5,10,15,20-tetra(4-aminbiphenyl) porphyrin (TAPP) and 4,4′-biphenyldicarbaldehyde (BDA) as starting materials, which was then coordinated with cobalt to yield related metal complex (Co-PPOPs). The chemical structure and morphology of Co-PPOPs were characterized by absorption spectrum , FT-IR, X-ray photoelectron spectra (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and nitrogen physisorption . Co-PPOPs showed excellent catalytic activity towards the conversion of carbon dioxide to cyclic carbonates under ambient conditions. Furthermore, Co-PPOPs was recovered easily and could be used repeatedly (more than five times) without losing any catalytic activity. Thus, the as-prepared Co-PPOPs was a promising heterogeneous catalyst for carbon dioxide conversion, providing high turnover number than the previously reported catalysts.
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高影响因子
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2022
·
IF 4.383
Adil Raza,Azhar Ali Haidry,Jaffer Saddique
Efficient solar to chemical energy conversion by promising semiconductor-based photocatalysis has gained huge interest due to being a potential solution for environmental remediation and energy problems. Though, the inadequate photogenerated charge separation practically limits the photocatalytic efficiency. Herein, mesoporous g-C 3 N 4 (CN) nanosheets coupled Cu 2 ZnSnS 4 (CZTS) hybrid composite as visible-light-driven photocatalyst is synthesized by a facile in situ hydrothermal self-assembly method and investigated for CO 2 photocatalytic reduction. The hybrid composite shows a slight red shift to the visible region with enhanced optical absorption . Under visible light irradiation, experimental results exhibit CZTS-CN hybrid composite has CO/CH 4 yield rates of 12.01/3.76 μmol g −1 after 5h, which are 1.54/1.41 times higher in comparison with bare CN. The heterojunction formation between CZTS and g-C 3 N 4 is restraining the electron-hole recombination and improves the photocatalytic performance. Finally, acceptable underlying mechanisms for CO 2 photocatalytic reduction over CZTS-CN hybrid composite are proposed. This work may inspire readers to provide sufficient guidance to design high-performance photocatalysts.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Wei Yi,Diweina Zheng,Xianhua Wang,Yingquan Chen,Junhao Hu,Haiping Yang,Jingai Shao,Shihong Zhang,Hanping Chen
In this study, batched hydrothermal experiments on corn stalk were conducted at 240–330 °C under CO 2 or inert (N 2 ) atmosphere. The distribution and characteristics of gaseous, solid, and liquid products were analyzed in detail to comprehensively investigate the effects of CO 2 on the hydrothermal conversion of biomass, especially on the cellulose and lignin in biomass. The results demonstrate that compared with N 2 , CO 2 slightly increased the liquid and gas yields and significantly improved the control effect of temperature on bio-oil components. Under CO 2 atmosphere, bio-oil achieved effective enrichment of ketones and phenols at 240 °C and 300 °C, respectively, and their highest relative contents reached 44.8% and 62.0%, respectively. In addition, the hydrochar obtained under CO 2 atmosphere showed higher crystallinity , which is conducive to its subsequent utilization. This study explored the feasibility of introducing CO 2 into the biomass hydrothermal process to realize the high-value utilization of biomass waste and the reuse of CO 2 .
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PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2022
·
IF 10.53
Qinsheng Wang,Yiyi Fan,Chengliang Wu,Yun Jin,Claudia Li,Jaka Sunarso,Xiuxia Meng,Naitao Yang
Research on gas separation membrane has targeted upon maximizing the selectivity and permeance. The development of 2D materials ( e.g. , MXene) gives a novel avenue to surpass the “trade-off” among the membrane selectivity and permeability. However, randomly stacked nanosheets and the regulation of interlayer spacing for MXene nanosheets hinder the development of MXene membrane. To this end, we designed a Pd-intercalated lamellar MXene membrane to modify the surface chemical properties (H-spillover effect) of MXene (Ti 3 C 2 T x ) and to expand the interlayer spacing (from 2.29 to 3.26 Å) due to the strong interaction between Pd 2+ and MXene nanosheets with negative charge. Here, we performed a single-step etching approach to prepare 2D Pd-MXene membrane and demonstrated its excellent H 2 permeability of 2.66 × 10 −7 mol m −2 s −1 ·Pa −1 and H 2 /CO 2 selectivity of 242 at 25 °C, which greatly exceeds the current benchmark membranes. We also developed single gas transport mathematical mechanism models to interpret and support the experimental results. The combined experimental and modeling results show that interlayer spacing and H-spillover effect of Pd-MXene membrane benefit H 2 /CO 2 separation.
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高影响因子
INORGANIC CHEMISTRY
·
2019
·
IF 4.85
Shikang Yin,Jinze Li,Linlin Sun,Xin Li,Dong Shen,Xianghai Song,Pengwei Huo,Huiqin Wang,Yongsheng Yan
Photocatalytic reduction of CO2 by semiconductors is of great significance in generating value-added fuels. Here, we construct a novel S–C–S heterojunction constituted of MoS2/SnS2/r-GO by a simple solvothermal method. The prepared MoS2/SnS2/r-GO showed significant photoexcitation of photosensitive oxygen (ROS) by electron spin resonance spectroscopy, demonstrating that superoxide radicals (•O2–), pores, and hydroxyl radicals (•OH) are the main active species. The constructed S–C–S heterojunction has a multilevel electron transport mechanism and synergistic effect, which provides the possibility of producing more organic fuel. The photocatalytic materials were characterized by XRD, XPS, SEM, TEM, PL, etc. As a result, the atomic layer MoS2/SnS2/r-GO heterojunction exhibited a CO formation rate of 68.53 μmol g–1 h–1 and a CH4 formation rate of 50.55 μmol g–1 h–1, respectively. This work opens up new prospects for the formation of heterojunctions of chalcogenide transition-metal sulfides.
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PubMed
高影响因子
Soft Matter
·
2017
·Vol. 13
·期 34
·5704-5713
·
IF 3.889
Cheng Wang,Mengnan Zhang,Wei Li,Xin Huang,Shuang Li,Sen Luan,Xiaojian Hou,Qian Wang
A systematic study on the structural properties and component information of periodic mesoporous organosilicas synthesized by using different nonionic surfactants as templates with compressed CO2 was carried out. Triblock copolymers (F127, F108, and P123), oligomeric alkyl poly(ethylene oxide) (Brij-58 and Brij-76), and alkyl-phenol poly(ethylene oxide) (TX-100) have been employed as templates and BTEB as a bridged organosilica precursor to synthesize PMO materials at 5.90 MPa. The structure and morphology of the obtained materials were investigated by means of transmission electron microscopy (TEM), nitrogen sorption isotherms, solid Si and C NMR, and FTIR. Efforts have also been made to compare the differences in structural and morphological properties among these samples synthesized under similar conditions. We also investigate the synthesis of PMOs using F127 as the template at different CO2 pressures. It was found that the interaction between different organic silica precursors and surfactants with a variety of hydrophilic and hydrophobic chains is the key factor for the disorder degree of mesostructures. On this basis, the possible mechanism of formation of PMOs synthesized using a nonionic surfactant (triblock copolymer) as the template with compressed CO2 is illustrated and discussed.
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高影响因子
RSC Advances
·
2020
·Vol. 10
·期 69
·42408-42412
·
IF 3.119
Yuying Yang,Hong Li,Supeng Pei,Feng Liu,Wei Feng,Yongming Zhang
CO2, the main greenhouse gas, has received considerable attention due to environmental issues. From a scientific perspective, CO2 as a cheap and abundant carbon source, could be applied in synthesizing more valuable chemicals such as urea, formic acid, and cyclic carbonates. However, the high bond energy of CO (750 kJ mol−1) and the non-polarity property make CO2 molecules difficult to activate. In this paper, we have carefully designed a low-cost, stable and, most importantly, highly efficient Co-based heterocatalyst Co@NxC functionalized by nitrogen-doped carbon to activate CO2 molecules and convert it into cyclic carbonates. The CO2 conversion process could be triggered at very mild conditions (60 °C and 1 bar CO2). We carefully adjusted the nitrogen content in the carbon support to enhance the catalytic performance of Co centers via the interface effect. Consequently, the optimal catalyst displayed extraordinary activity toward the cycloaddition of CO2 with styrene oxide as high conversion (92%) and selectivity (>99%) were achieved in 4 h without byproducts.
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高影响因子
ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Xiangfu Meng,Guoxing Pan,Hongji Liu,Yong Qian,Xingyu Wang,Changlai Wang,Lin Hu,Hui Wang,Qianwang Chen
The electroreduction of carbon dioxide (CO2) to a liquid product is a viable method for establishing an artificial carbon cycle. Unfortunately, most electrocatalysts’ low efficiency and instability prevent them from being used in practical applications. In the current study, we developed ultrasmall Cu nanocrystals embedded in nitrogen-doped carbon nanosheets (Cu/NC-NSs) for selective CO2 electroreduction by adjusting the potential. Cu/NC-NSs had 43.7 and 63.5% Faradaic efficiencies for the synthesis of ethanol and formate with applied potentials of −0.37 and −0.77 V vs reversible hydrogen electrode (RHE) using a flow cell architecture, respectively. Moreover, these Cu/NC-NSs show a steady catalytic performance up to 16 h. Density functional theory (DFT) calculations were performed to investigate the reaction mechanism. Furthermore, the synergistic effect formed by nitrogen-doped carbon and highly dispersed copper atoms led to their excellent performance in CO2 electroreduction.
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