ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Yanwei Sun,Chunshan Song,Xinwen Guo,Yi Liu
Preferred orientation has proven to exert a significant impact on the gas separation performance of metal–organic framework membranes. Nevertheless, realizing three-dimensional orientation control remains a challenging issue. In this study, well-intergrown NH2-UiO-66 membranes with both (111) out-of-plane and regional in-plane orientations were prepared by combining oriented deposition of seeds and solvothermal epitaxial growth. Dynamic air–liquid interface-assisted self-assembly method was employed to organize uniform octahedral-shaped NH2-UiO-66 seeds into closely packed monolayers with (111) out-of-plane and regional in-plane orientations, whereas the use of ZrS2 as the zirconium precursor during the solvothermal epitaxial growth was found indispensible for sealing the intercrystalline gaps while preserving the preferred orientation inherited from seed layers. In addition, compared with solvothermal heating, employing microwave heating led to poor intergrowth between neighboring NH2-UiO-66 crystals because of a lower dielectric loss factor of the reaction medium. Gas permeation results indicated that the prepared NH2-UiO-66 membranes exhibited H2/CO2 selectivity up to 5.5 times higher than their counterparts with random and/or mere out-of-plane orientations as well as H2 permeability 14.5 times higher than NH2-MIL-125(Ti) membranes with mere out-of-plane orientation under similar operating conditions.
研究领域:
材料科学
·
化学工程
·
膜技术
✓ 已验证
DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Liang Qin,Yan Li,Fenglan Liang,Lijun Li,Yuwen Lan,Zhiyong Li,Xiaoting Lu,Manqi Yang,Deyun Ma
A new microporous 2D Co-based MOF , [Co 3 (C 6 H 3 NO 2 ) 2 (cpna) 2 (DMA) 2 ] n ( 1 ) (H 2 cpna = 6-(4-carboxylphenyl)nicotinic acid; DMA = N,N-dimethylacetamide), has been synthesized and structurally characterized. Complex 1 shows a 2D network with 1D channel of 6.4 × 9.3 Å 2 along the a -axis. Activated 1 ( 1a ) exhibits selective gas adsorption for CO 2 as compared to other gas molecules ( e.g. C 2 H 2 , CH 4 , CO, N 2 ) from the experimental single-component gas-adsorption isotherm (at 273K and 298K), molecular simulation and breakthrough experiments (298K). And the adsorption selectivity (CO 2 /C 2 H 2, CO 2 /CH 4, CO 2 /CO, and CO 2 /N 2 ) was calculated with the ideal adsorbed solution theory (IAST). Activated 1 shows 9.77 wt% (2.22 mmol/g) uptake of CO2 at 1 bar and 273 K. Furthermore, the activation of 1 exhibits high ideal selectivities in adsorption of CO 2 over C 2 H 2 , CH 4 , CO, and N 2 at 298 K (1 bar), which may be attributed to the pyridyl sites on the ligands and open metal sites on the nodes of the framework. Besides, 1a could adsorb more gas molecules due to thicker layer (10.97 Å) of 2D structure.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2023
·
IF 5.9
Xueyan Chen,Shuo Hu,Xiaoxiao Qin,Min Chen,Jianghao Zhang,Xiaolei Bao,Changbin Zhang
Ag-based catalysts have been extensively investigated in HCHO oxidation on account of the low price of the Ag precursor and their considerable low-temperature activity. It is known that H2 pretreatment has a remarkable promotion effect on Pt- and Pd- catalysts for HCHO oxidation, whereas the effect of H2 reduction on Ag-based catalysts has been rarely reported, probably due to the coexistence of multiple states of Ag species resulting from the high Ag loading. Herein, we prepared a 1% Ag/Al2O3 (Ag/Al-fresh) catalyst with Ag species in a uniform state and then reduced Ag/Al-fresh with H2 at 600 °C to obtain the Ag/Al-600H2 catalyst. We observed that H2 reduction had a significant influence on the performance of Ag/Al2O3 nanocatalysts in HCHO oxidation. In a dry reaction atmosphere, Ag/Al-fresh and Ag/Al-600H2 exhibited comparable HCHO conversion levels, but Ag/Al-600H2 showed much higher CO2 selectivity than Ag/Al-fresh. The presence of water vapor severely suppressed the HCHO conversion of the Ag/Al-fresh catalyst, while Ag/Al-600H2 showed high water resistance, maintaining high HCHO conversion and CO2 selectivity at 35% RH. Characterization results showed that the Ag species on Ag/Al-fresh and Ag/Al-600H2 were single-atom cationic Ag and metallic Ag nanoparticles, respectively. It was revealed that the Ag0 nanoparticles were more conducive than single-atom Ag+ to formate decomposition, as well as O2 and H2O activation, thus accelerating the conversion of HCOO– and CO intermediates to CO2 and contributing to the higher activity and water resistance of the Ag/Al-600H2 catalyst.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Yongbiao Sun,Hui Li,Haijun Lai,Yan Yu,Meiling Hou,Chao Fu,Zaizhou Wang,Chunxiang Zhang
Natural gas purification before liquefaction necessitates the use of efficient adsorbents with high selective CO 2 adsorption and easy regeneration. Because of its efficiency and ease of operation, the ion exchange is widely employed to adjust zeolites’ CO 2 adsorption. However, few in-depth mechanistic studies have been undertaken on cation substitution regulation of pore structure and gas–solid interaction, as well as their synergistic effects on CO 2 selective adsorption and zeolite regeneration. In this study, we synthesized Li + and K + -modified 13X and examined their material characteristics, thermodynamics, adsorption kinetics, and the adsorption–desorption performance under various desorption methods. The results showed that the variation in pore structure and gas–solid interaction with cation radius is non-monotonic, resulting in 13XLi and 13XK having better CO 2 selective adsorption than 13X. All zeolites are extremely stable after 10 adsorption–desorption cycles in each regeneration setting. 13X outperforms 13XLi and 13XK in CO 2 desorption at 30 °C, owing to its large non-micropore volume and low gas–solid interaction. 13XK has the lowest CO 2 desorption rate at low temperature but the highest at high temperature, owing to the flat micropore distribution and the progressive gas–solid interaction. Approximately 100 % regeneration of 13XK is achieved with CH 4 purging (150 mL/min) at 150 °C, owing to its smallest cumulative pore volume at 0.5 nm. This research could help to develop efficient cation-modified X zeolites for CO 2 deep removal from CH 4 streams prior to liquefaction, as well as advance the in-depth understanding of cation substitution mechanisms.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Xiaochang Cao,Zhi Wang,Zhihua Qiao,Song Zhao,Jixiao Wang
Developing mixed matrix membranes (MMMs) is challenging because the interface between different matrices often forms undesirable structures. Herein, we demonstrate a method of creating suitable CO2-selective channels based on interface regulation that greatly enhances membrane separation performance. The poly(vinylamine), which also acts as a polymer matrix, was immobilized onto covalent organic frameworks (COFs) to obtain polymer–COF hybrid materials (COFp). The COFp and polymer matrix are highly compatible because they have the same segment. The polymer matrix was induced to penetrate the oversized COFp, resulting in an amino-environmental pore wall and appropriately sized CO2-selective channels dispersed in MMMs. The MMMs exhibited satisfactory membrane performance for CO2/N2, CO2/CH4, and CO2/H2 separation. A CO2 transport model for preferential adsorption and transport is clearly presented for the first time. The membrane separation mechanism is also discussed. This work demonstrates potential applications for material, interface, and membrane investigations.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
Catalysts
·
2022
·Vol. 12
·期 7
·775
·
IF 4.501
Yang Liu,Gongda Chen,Jianjun Chen,Hejingying Niu
Metal organic framework (MOF) is a type of porous organic material. In this work, three catalysts loaded with noble metal Pt were prepared by NaBH4reduction method with three different morphologies of Ce–MOF as carriers. Their physicochemical properties were characterized by XRD, Raman, FTIR, N2adsorption, SEM, XPS, and TGA. The catalytic performances of different catalysts were evaluated via toluene oxidation and CO2selectivity. Rod–shaped Pt/MOF–BTC exhibited best catalytic performance compared to Pt/MOF–808 and Pt/UiO–66, its T50and T90were 140 °C and 149 °C, respectively. After deducting the effect of specific surface, Pt/MOF–BTC still had the lowest apparent activation energy (62.8 kJ·mol−1), which is due to the abundant atomic Pt and oxygen vacancy content on its surface. After the reaction, the structure of Pt/MOF–BTC may become amorphous according to XRD results. Furthermore, the presence of amorphous structure had no effect on the catalytic activity of the catalyst. In the stability test of Pt/MOF–BTC to toluene oxidation, both toluene conversion and CO2selectivity remained at 100%, and remained stable for 11 h. Moreover, Pt/MOF–BTC also had better resistance to high weight hourly space velocity (WHSV) or water resistance. The catalyst maintained high catalytic activity for 3 times reusability. This study provides valuable experience for the future work of MOF in the field of VOC catalytic oxidation.Keywords:Ce–MOF;noble metal;oxygen vacancy;catalytic oxidation
研究领域:
催化
·
材料科学
·
环境化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Kejing Wang,Yongjun Liu,Zhiwen Li,Nan Cui,Lei Sun,Wei Huang
The valence states of Cu site are regarded as an important factor affecting the performance of syngas to higher alcohols (C 2+ OH). Regrettably, the role of Cu 0 and Cu + in CO hydrogenation to higher alcohols remains controversial due to the complexity of the reaction. In this study, Cu 0 and Cu 2 O powders are directly added as the precursors to adjust the ratios of Cu + /(Cu 0 +Cu + ) and Cu particle sizes in CuZnAl catalysts by a complete liquid-phase (CLP) technology. The CAT-Cu 0 catalyst with higher Cu 0 content shows the highest CO conversion (>15%) ascribing to the biggest S Cu , but is also accompanied by the highest CO 2 selectivity (>40%), while the CAT-Cu + catalysts with higher Cu + content displays relative better C 2+ OH selectivity (>60%) and stability due to a higher probability of CO insertion. In-situ DRIFTS experiments reveal that a synergy between larger Cu particle sizes (30～40 nm) and surface Cu + sites, in which larger Cu sizes enhances the probability of bridge CO adsorption, thereby favoring the C–O bond dissociation for CH x formation. Meanwhile, Cu + active sites provide a higher probability for CO/CHO insertion to form CH 3 CHO*/CH 2 CO* intermediates. This study further deepens our understanding of the critical controlling factors for highly selective synthesis of C 2+ OH from syngas over Cu-based catalysts.
研究领域:
化学工程
·
催化
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Yuchao Chen,Yubin Wang,Zifei Yan,Jian Deng,Guangsheng Luo
Efficient selective removal of H 2 S over CO 2 is the critical absorption process for the gas desulfurization in the petrochemical and refining industries. In this work, we tried to achieve high-selective removal of H 2 S from a mixed gas with CO 2 using a nonaqueous methyldiethanolamine solution in a membrane gas–liquid microdispersion microreactor. The influence of structural parameters and operation parameters on the removal efficiency of H 2 S and CO 2 were systematically investigated. In addition, the mechanism of selective absorption H 2 S over CO 2 was explained in detail. Furthermore, the selective absorption performance of the membrane microdispersion microreactor was compared with other devices. The results showed that the H 2 S removal efficiency and selective factor could be up to 99.4 % and 16.6, respectively. The selectivity factor of H 2 S to CO 2 in the membrane microdispersion microreactor is higher than that of most of reported devices. This work provides a promising selective absorption H 2 S device and technology for the process intensification of gas desulfurization.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Weicheng Xu,Bingxu Chen,Xueding Jiang,Feng Xu,Xin Chen,Limin Chen,Junliang Wu,Mingli Fu,Daiqi Ye
The effect of Ca modification on the Ni/ZSM-5 catalyst for efficient toluene oxidation was studied in a plasma-catalytic system. The Ni/ZSM-5 and Ca-Ni/ZSM-5 catalysts were prepared by a wet impregnation method and characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Pyridine-FTIR spectroscopy and temperature programmed desorption of ammonia (NH 3 -TPD). Among the catalysts tested, the Ca-Ni/ZSM-5 sample showed the best potential for toluene conversion (90.2%) and CO 2 selectivity (70.7%). Pyridine-FTIR spectra and NH 3 -TPD results proved that the introduction of Ca and Ni onto ZSM-5 caused a decrease in the strong and weak acidic sites. In addition, gas chromatography/mass spectrometry (GC-MS) result showed that the Ca-Ni/ZSM-5 catalyst reduced the production of undesirable byproducts (such as p-nitrotoluene and methyl benzoate). Calcium in the Ni/ZSM-5 system influenced the acidity and other surface characteristic of the catalyst, as well as directly impacting the reactive plasma species and the intermediates. Finally, possible reaction mechanisms in the plasma catalysis of toluene were also proposed.
研究领域:
环境催化
·
大气污染控制
·
材料化学
·
表面科学
·
等离子体化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2021
·
IF 8.742
Chenhan Zhang,Jiahui Yan,Taotao Ji,Dongying Du,Yanwei Sun,Liangliang Liu,Xiongfu Zhang,Yi Liu
Preferred orientation represents a main concern for microstructure control and performance optimization of MOF membranes. To date, it remains a challenging task to precisely control preferred orientation of ZIF-8 membrane. Herein, we prepared highly (110)-oriented ZIF-8 membrane by oriented secondary growth. Among various elements, preparation of uniform ZIF-8 nanosheet seeds through thermal conversion of identically shaped ZIF-L precursors, spin-coating-assisted oriented deposition of (110)-oriented ZIF-8 seed layer, and controlled in-plane secondary growth at low temperature were found crucial for obtaining well-intergrown (110)-oriented ZIF-8 membrane whose H 2 /CO 2 ideal selectivity exceeded H 2 /N 2 and H 2 /CH 4 under ambient conditions, owing to preferential CO 2 adsorption capacity of not only PEI but also ZIF-8 nanosheets compared with their bulk counterparts. Our research highlighted the significance of preferred orientation regulation in tailoring the gas permeation behavior of MOF membranes.
研究领域:
材料科学
·
化学工程
·
膜技术
✓ 已验证
DOI
高影响因子
Catalysts
·
2022
·Vol. 12
·期 7
·716
·
IF 4.501
Xinbo Zhu,Xiqiang Wu,Jin Liu,Jianbin Luo,Zhengda Yang,Ye Jiang,Geng Chen
In this work, soot oxidation was conducted over a series of Mn-X/γ-Al2O3(M = Ce, Co and Cu) binary catalysts in a dielectric barrier discharge reactor. The soot conversion in the plasma–catalytic system was in the order of Mn/γ-Al2O3(57.7%) > Mn-Co/γ-Al2O3(53.9%) > Mn-Ce/γ-Al2O3(51.6%) > Mn-Cu/γ-Al2O3(47.7%) during the 30 min soot oxidation process at 14 W and 150 °C. Meanwhile, the doping of Ce, Co and Cu slightly improved the CO2selectivity of the process by 4.7% to 10.3% compared to soot oxidation over Mn/γ-Al2O3.It is worth to note that the order of CO2selectivity was in the opposite order with soot oxidation rate. The effects of discharge power, oxygen content in the carrier gas and reaction temperature on plasma–catalytic soot oxidation was systematically analyzed. The catalyst characterizations, including N2adsorption–desorption, X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction by H2and temperature-programmed desorption of O2,were conducted to illustrate the reaction mechanisms of plasma–catalytic soot oxidation and reaction pathways.Keywords:plasma–catalysis;soot oxidation;manganese-based oxides;transition metal;binary catalyst
研究领域:
环境科学
·
催化
·
等离子体化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Minmin Gou,Weifang Zhu,Yanyong Sun,Ruili Guo
Two-dimensional (2D) MOF named Cu(BPY) 2 (OTF) 2 (OTF = trifluoromethanesulfonic acid anion (CF 3 SO 3 − ), BPY = 4,4-bipyridine) possessing axial coordination anion was prepared, and then combined into Pebax® MH 1657 (Pebax) polymer to fabricate mixed matrix membranes (MMMs) for the separation of CO 2 /CH 4 gas mixtures. The inherent microporous structure and interlayer nanochannel that constructed by axial coordination anion CF 3 SO 3 − of Cu(BPY) 2 (OTF) 2 nanosheets provide selective transfer channels for CO 2 . In addition, the group that has an affinity for CO 2 , such as pyridine group and CF 3 SO 3 − anion, locating in the surface and the interlayer of Cu(BPY) 2 (OTF) 2 nanosheets, present better binding affinity and molecule selectivity for CO 2 . Owing to the synergistic effect between structure and functional groups of Cu(BPY) 2 (OTF) 2 nanosheets, the optimized CO 2 separation performance (permeability and selectivity) of the MMMs compared with that of pure Pebax were increased by 86.65% and 47.59%, respectively, under the conditions of pure gas, 0.1 MPa and 25 °C. The open narrow nanochannels and axial coordination anion in Cu(BPY) 2 (OTF) 2 nanosheet, making Cu(BPY) 2 (OTF) 2 a promising material to prepare efficient mixed matrix membrane.
研究领域:
材料科学
·
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）