Nanoscale
·
2020
·Vol. 12
·期 46
·23694-23699
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IF 6.895
Qinzhen Li,Sha Yang,Tao Chen,Shan Jin,Jinsong Chai,Hui Zhang,Manzhou Zhu
It is of great interest to investigate the evolution pattern of gold nanoclusters (Au NCs) due to its significance in understanding the growth mechanism and origin of Au NCs. Capture of metastable cluster intermediates is an effective way to meet this demand since they provide valuable information for understanding the conversion pathway of Au NCs. However, it is still challenging to obtain metastable Au NCs, especially thiol-protected Au NCs, and solve their structures. In this work, a metastable thiol-protected gold nanocluster, Au22(SAdm)16 (Au22), was synthesized and its structure was determined by single crystal X-ray diffraction. Au22 shows a close structure-evolution correlation with Au21(SAdm)15 (Au21). The symmetric Au10 kernel of Au21 is twisted by the insertion of an additional Au-SR unit on the motif during its structure evolution into Au22. The distortion in structures results in significantly distinguishing absorption and emission spectra between Au22 and Au21. Noteworthily, the structure correlation between Au22 and Au21 was also found experimentally that Au22 can spontaneously transform into Au21 due to the metastability of Au22 in solution. This size conversion process was monitored by time-dependent UV-vis spectroscopy and ESI-MS. Furthermore, the solvent effect on the size conversion process was also investigated. This transformation from Au22 to Au21 provides a unique platform for studies on the evolution pattern of gold nanoclusters at the single atom level.
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ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Juncheng Yang,Yihong Jia,Benhua Huang,Xiaoyong Li,Lina Guo,Aqun Zheng,Rafael Luque,Yang Sun
1,4-Sorbitan and 1,4-mannitan are important precursors for the synthesis of detergents and pharmaceuticals, derived from mono-dehydration of sugar alcohols (d-sorbitol and d-mannitol). In order to improve mono-dehydration selectivity, functionalized CeO2/SBA-15 materials were synthesized and employed as dehydration catalysts. Characterization revealed that all synthetic catalysts contain cerium dioxide nanoparticles with sizes below 10 nm. All prepared catalysts provided 1,4-sorbitan or 1,4-mannitan as the major dehydration products in water at room temperature, with catalysts being nicely active and stable after several reuses.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2020
·
IF 2.369
Xudong Zheng,Zhiqiang Song,Enxiu Liu,Yuzhe Zhang,Zhongyu Li
Phosphoric acid-functionalized mesoporous silica material was prepared by copolycondensation using P123 as the soft template and diethylphosphatoethyltriethoxysilane as the functional monomer. It was used for highly efficient selective adsorption and separation of La(III). By adjusting the ratio of the silicon source to functional monomer, the difference of the adsorption material structure and the change of adsorption performance were explored. When the ratio of the silicon source to functional monomer is 9/1, the phosphoric acid-functionalized SBA-15 (named S2) exhibits a highly ordered hexagonal cell structure. Saturated adsorption capacity of La(III) on S2 is 114.81 mg g–1 at 25 °C and 7.0 pH, which is much larger than other reported adsorbents. In addition, the adsorbent S2 has excellent adsorption kinetics: the adsorption equilibrium can be quickly concluded within 60 min. The distribution coefficient (Kd) of S2 to La(III) is 725 mL g–1, and that of Nd(III) and other ions is about 200 mL g–1. This indicates that the phosphoric acid-functionalized adsorbent has strong selectivity in the process of adsorption and separation of La(III). Cyclic performance tests indicate that the adsorbent has excellent regenerability. The above results indicate that the phosphoric acid-functionalized SBA-15 adsorbent (S2) has a promising application in the actual adsorption separation of La(III).
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JOURNAL OF MOLECULAR LIQUIDS
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2020
·
IF 5.065
Kui Wu,Yajun Li
Being an important synthetic monomer , isobutyramide (IBA) is employed as an intermediate for the synthesis of organic dyes and pharmaceuticals. It is well known that investigation of the solubility behavior of drugs and intermediates has become an extensive research topic in pharmaceutical development. In this work, the solid-liquid equilibrium (SLE) data of IBA in fifteen solvents, including methanol, ethanol, n -propanol, isopropanol, n -butanol, isobutanol , acetonitrile , chloroform, acetone, ethyl formate , methyl acetate , cyclohexanone , cyclopentanone , tetrahydrofuran and 2-butanone was measured with a static gravimetric method with the temperature ranging from 273.15 to 324.75 K under atmospheric pressure. The solubility of IBA increases with the rising temperature in all selected solvents. The ranking of solubility in various solvents is not in accordance with the order of solvent physicochemical properties, namely polarity index, dipole moment , dielectric constant and solubility parameter. The modified Apelblat equation, λh equation, nonrandom two-liquid (NRTL) model and the Wilson model were used to correlate the experimental data. Maximum root-mean-square deviation ( RMSD ) and relative average deviation ( RAD ) were 7.157 × 10 −3 and 1.80%, respectively. The λh equation presented less effective correlating results compared with other three models. The dissolution properties of IBA, including Gibbs energy (△ dis G ), molar enthalpy (△ dis H ) and molar entropy (△ dis S ) were determined based on the Wilson model and the solubility data. Positive values of the dissolution enthalpy and entropy illustrated that the dissolution process of IBA in selected solvents are endothermic and entropy-driven.
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Journal of Environmental Chemical Engineering
·
2020
·
IF 4.3
Jianlin Zhang,Tao Zhuang,Shanjun Liu,G.C. Zhang,Kaili Huo
A mesoporous MnO 2 (M-MnO 2 ) was prepared by nanocasting method with SBA-15 as the hard template, and was investigated as an ozonation catalyst. The composition and morphology of the as-prepared MnO 2 were characterized using X-ray diffraction analysis, transmission electron microscopy and surface area analysis. The ordered nanorods with high surface area (100 m 2 g −1 ) helped the mass transport and the active sites exposed, and thus enhanced the efficiency of catalytic ozonation. The adsorption capacity of M-MnO 2 on phenol was about 8 times as high as that of the control MnO 2 (C-MnO 2 ) calculated by the Langmuir adsorption model(10.47 mgg −1 vs 1.20 mgg −1 ). Hydroxyl radical was identified as the main reactive oxygen species, and the hydroxyl radical yield from M-MnO 2 is about 2-fold enhanced compared with that from C-MnO 2 . Benefiting from the high mass transport and abundant active sites exposed, the TOC removal of phenol catalyzed by M-MnO 2 (35%) was much better than that by C-MnO 2 (27%)in 30 minutes.
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JOURNAL OF SOLID STATE CHEMISTRY
·
2019
·
IF 2.291
Xiangping Li,Han Yin,Jianguang Zhang,Juping Liu,Guanyi Chen
Template removing approaches can significantly impact the physiochemical properties of mesoporous molecular sieve materials. In order to better understand the relationship between template removing approaches and the properties of Ni/Al-SBA-15, four kinds of template removing approaches were introduced to remove the organic template from Al-SBA-15, respectively. The structural characteristics of these materials were analyzed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray fluorescence (XRF), powder X-ray diffraction (XRD), N 2 -sorption, Fourier transform infrared spectra (FT-IR), infrared spectra of pyridine adsorption (Py-FTIR), magic angle spinning-nuclear magnetic resonance (MAS-NMR), X-ray photoelectron spectroscopy (XPS) and gas chromatography-mass spectrometry (GC-MS). Ni/Al-SBA-15 of which the organic template was removed by two-step calcination method had the maximum specific surface area (619 m 2 /g). In contrast, Ni/Al-SBA-15 of which the organic template was removed using solvent extraction approaches had the lowest specific surface area (555 m 2 /g). The mesopore diameter of Ni/Al-SBA-15, using electric heating digestion method to remove the template, was significantly increased and the wall thickness was significantly decreased to 11.62 nm in comparison with the other samples. The selectivity of products during the process of eugenol hydrodeoxygenation was investigated. High hydrocarbons were obtained during catalytic hydrodeoxygenation over Ni/Al-SBA-15 of which the organic template was removed by using solvent extraction approaches. Compared with direct calcination process, two-step calcination was more effective in removing template and the corresponding catalyst was much more suitable for the hydrodeoxygenation process.
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MOLECULES
·
2024
·Vol. 29
·期 17
·4230
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IF 4.2
Yan Gao,Shuai Huang,Nina Han,Jianshe Zhao
In this work, a novel heterogeneous catalyst consisting of peroxophosphotungstate, microporous MOF-808, and mesoporous SBA-15 was synthesized, characterized, and used to remove sulfides from model fuel. The prepared material, PW4@MOF-808@SBA-15, exhibits excellent catalytic activity with a desulfurization efficiency of 99.8% in 60 min for multicomponent simulated fuel, and the desulfurization rate can reach more than 90% after ten consecutive cycles. The excellent catalytic activity and reusability are attributed to the hierarchically porous hybrid material MOF-808@SBA-15, which can effectively encapsulate PW4and provide a site for the oxidation of sulfides.
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RSC Advances
·
2016
·Vol. 6
·期 73
·68695-68704
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IF 3.289
Yiming Ren,Ruizhu Yang,Lang Shao,Hao Tang,Shaofei Wang,Jianlong Zhao,Jingrong Zhong,Chuipeng Kong
Phosphoramide-modified ordered mesoporous silica (SBA-DEPA) materials were prepared via a two-step process involving: (1) the synthesis of phosphoramide via amidation of phosphoryl chloride with a primary amine and (2) modification of the phosphoramide onto SBA-15. The successful preparation was confirmed by FT-IR and NMR spectroscopy. As indicated by the ICP-AES and XRF analysis results, the phosphoramide group has a grafting ratio as high as 12.5%. The morphological information and N2 adsorption–desorption technique proved the highly ordered structure and large specific area of the material, respectively. An excellent performance for uranium sorption was found with a loading maximum of 311.6 mg g−1, a marked promotion relative to unmodified SBA-15. A strong pH and CO2 dependence suggested that near neutral conditions favored the maximum uranium sorption. To our surprise, the sorption took only 5 min to reach a 90% capacity and 20 min for equilibrium, which is extraordinary when compared to many other sorbent materials. The ionic strength partially influences the sorption, which indicates outer and inner sphere sorption both play parts in the process. A sorption capacity of over 90% of the original indicates the excellent reproducibility of SBA-DEPA. DFT calculations based on cluster models suggested a ‘tri-dentate-like’ structure for the uranyl-surface binding site, which may explain the excellent sorption ability of this material.
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CATALYSIS COMMUNICATIONS
·
2017
·
IF 3.33
Junyi Liu,Hua Huang,Xianxiang Liu,Jiafu Xiao,Sheng Zhong,Xichun She,Zaihui Fu,Steven Robert Kirk,Dulin Yin
A series of Fe 2 O 3 doped SBA-15 materials were prepared via an equivalent-volume impregnation method. The resultant Fe 2 O 3 -containing SBA-15 materials showed good performance in phenol methylation . Under the same conditions, the mesoporous catalyst with 5 wt.% Fe 2 O 3 showed the superior catalytic activity to that of pristine α -Fe 2 O 3 even at lower reaction temperature (320 °C vs. 350 °C). The elevated catalytic activity observed for the mesoporous catalyst could be due to high level dispersion of Fe 2 O 3 species in the mesoporous framework. Furthermore, the mesoporous catalyst possessed long lifetimes, which could be used continuously for 2000 h without significant loss of activity.
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RESEARCH ON CHEMICAL INTERMEDIATES
·
2013
·Vol. 40
·期 1
·385-397
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IF 0.88
Wang Yong,Chen Guihua,Zhang Fumin,Li Liquan
Ni-incorporated SBA-15 magnetic composites were two-stage hydrothermal synthesized from initial strong acidic media through a pH-adjusting method. The structure, morphology, surface area and pore size distribution of the samples were systematically characterized by using XRD, FT-IR, SEM, TEM and N 2 physical adsorption techniques. It was found that, when pH was adjusted to 7, the obtained sample still could exhibit hexagonal mesostructure, very similar to that of the pristine SBA-15 except for a slightly reduced long-range ordering and surface area. However, an increase in the unit cell and wall thickness of the samples suggested the more Ni species were incorporated into the framework of SBA-15. A further increase in pH to 9 produced deterioration of long-range ordering of the sample, possibly resulting from the blocking of some mesopores. Thus, the pH-adjusting method played an important role on the structure of Ni–SBA-15 composites. Measurements taken with increasing applied field revealed the samples having superparamagnetic behaviors. Furthermore, the saturation magnetization values were increased with the more Ni species transforming into magnetic nanoparticles by the increasing pH.
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JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
·
2012
·
IF 2.947
Hui-xue Ren,Han-jie Ying,Ping-kai Ouyang,Ping Xu,Jing Liu
Efficient and pollution-free catalysts play an essential role in the ultimate biodegradation of products in the synthesis of biodegradable and recyclable poly( l -lactic acid) (PLLA). Therefore, macroporous resin was utilized as the solid acid for the first time, on which lactate that could be absorbed in vivo was composited to catalyze the synthesis of PLLA. It was discovered that macroporous resin Amberlyst-15 showed good catalytic activity in oligomerization and polymerization, and lactate showed different catalytic efficiencies due to the differences in ionic radius and ionic charge. Compared to the traditional catalysts of SnCl 2 ·2H 2 O/TSA, the composite catalyst can improve the quality, yield and optical purity of its product, which can also be recycled without any residual in products. PLLA with molar mass of about 110,000 g mol −1 was synthesized at the yield of 93%. The product exhibits pure color (white), and its optical purity and crystallinity are 98% and 55%, respectively. A possible catalytic mechanism was proposed. The resulting PLLA products were characterized by GPC, 1 H NMR, DSC, and polarimeter.
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CHEMICAL ENGINEERING JOURNAL
·
2014
·
IF 4.058
Wenjing Ding,Wenshuai Zhu,Jun Xiong,Lei Yang,Aimin Wei,Ming Zhang,Huaming Li
A novel catalyst, based on iron-based redox ionic liquid modified mesoporous SBA-15 material was successfully prepared and applied to the removal of sulfur compounds in model oil. Sample structures were extensively studied by XRD, N 2 adsorption–desorption, TEM, FTIR, DRS, and XPS analysis. This strategy provided a catalyst system with high surface area, high accessibility for substrate and oxidant. In the process of extractive catalytic oxidative desulfurization (ECODS) of model oil, [Omim]BF 4 served as not only the extractant and the reaction media but also co-catalyst. Under the optimal conditions, the sulfur removal could reach 94.3%. The mechanism of the ECODS system was also proposed.
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危险品化学品经营许可证（带存储）