Tiandi Tang

Wenzhou University, Yung-chia, Zhejiang Sheng, China

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Publications (19)90.23 Total impact

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    ABSTRACT: A magnesium oxide nanosheet assemblies (NS-MgO) with high surface area (255 m2/g) and nanopore volume (0.30 cm3/g) was prepared by a pressure-assisted carbonation method at large scale. After loading of cobalt and molybdenum (CoMo) species and followed by sulfidation, the NS-MgO supported CoMo catalyst (Co-MoS2/NS-MgO) exhibits high activity (94.2%) and good nitrogen tolerance in the hydrodesulfurization (HDS) of dibenzothiophene (DBT), compared with a conventional γ-alumina-supported CoMo catalyst (64.1%). These results are attributed to the difference in the basicity of the NS-MgO and γ-Al2O3 supports. The large amount of the middle strong basic sites on NS-MgO can avoid the polymerization of Mo species, and form small Mo oxide clusters. After sulfidation, the small MoS2 clusters with shorter lengths and less stackings formed on the NS-MgO contribute to an increase in the sites available for Co-promotion, resulting in the Co-MoS2/NS-MgO catalyst with high HDS activity.
    Industrial & Engineering Chemistry Research 05/2015; DOI:10.1021/acs.iecr.5b00452 · 2.24 Impact Factor
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    ABSTRACT: A Cu-doped zeolite ZSM-5 (Cu-ZSM-5-M) with a micro-meso-macroporous structure was directly synthesized, and it exhibits excellent catalytic activity and good recyclability in the cross-coupling of aryl halides with diphenyl disulfides. This feature should be attributed to the structural characteristics of meso-macropores and homogeneous dispersion of active Cu(δ+) (δ < 2) species in Cu-ZSM-5-M.
    Chemical Communications 03/2015; 51(27). DOI:10.1039/c4cc10417j · 6.72 Impact Factor
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    ABSTRACT: Developing highly active heterogeneous catalysts for the efficient construction of valuable building blocks is of great importance to synthetic chemistry. For this purpose, a mesoporous zeolite ETS-10 (METS-10) is synthesized by using a mesoscale silane surfactant as a template and applied to achieve highly efficient syntheses of α,β-epoxy ketones by employing simple alkenes and aldehydes as starting materials. The high activity of the METS-10 catalyst is attributed to its unique porous structure and basicity. Electron paramagnetic resonance characterization results and theoretical calculation experimental data reveal that the strong basic sites on METS-10 catalyst can activate the reaction substrate and intermediate. In addition, the mesopores in METS-10 catalyst benefit the mass transfer and further improve the catalytic activity.
    ChemCatChem 12/2014; DOI:10.1002/cctc.201402839 · 5.04 Impact Factor
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    ABSTRACT: Developing a low-cost route to synthesize mesoporous TS-1 (MTS-1) is of great importance because of its practical application in industry. Herein, we first synthesized a copolymer containing quaternary ammonium groups by a mesoporous template comprising inexpensive starting materials. Subsequently, waterglass (sodium metasilicate), TiCl3, and copolymer were dispersed in the preformed seeds emulsion, resulting in a gel for synthesizing MTS-1. The counterpart material (CTS-1) was also synthesized by the same procedure except for the absence of the copolymer. Compared with CTS-1, the MTS-1 exhibits good crystallinity and well-defined tetrahedral coordinated Ti species (Ti-IV) in the framework as well as excellent catalytic activity in the oxidation of bulky molecules, such as dibenzothiophene and benzyl phenyl sulfide. This feature may be attributed to the fact that the quaternary ammonium groups on copolymer facilitates the formation of the MFI structure and energetically incorporates the Ti species into the framework.
    Industrial & Engineering Chemistry Research 09/2014; 53(36):13903-13909. DOI:10.1021/ie502077q · 2.24 Impact Factor
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    ABSTRACT: Zeolite nanofiber assemblies (HNB-MOR) as efficient heterogeneous catalysts for the formation of a range of acetals in good yields. The mesoporosity of HNB-MOR benefits mass transfer, and the strong acidic sites on HNB-MOR facilitate acetalization activity. The catalyst can be reused 10 times without loss of activity.
    RSC Advances 01/2014; 4(35):18217. DOI:10.1039/c3ra47952h · 3.71 Impact Factor
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    ABSTRACT: Rich man, pore man: A facile and universal route to mesoporous zeolite TS‐1 (MTS‐1) is reported. Compared with mesoporous‐free TS‐1, the MTS‐1 zeolite shows extraordinarily catalytic activity and highly controllable chemoselectivity for the oxidation of sulfides into sulfoxides or sulfones. Based on the catalytic data, the Tihydroperoxo (η2) group is proposed to be the active site for the oxidation of sulfides into sulfoxides and sulfones.
    ChemCatChem 08/2013; 5(8). DOI:10.1002/cctc.201300084 · 5.04 Impact Factor
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    ABSTRACT: Developing highly active hydrodesulfurization (HDS) catalysts is of great importance for producing ultraclean fuel. Herein we report on crystalline mordenite nanofibers (NB-MOR) with a bundle structure containing parallel mesopore channels. After the introduction of cobalt and molybdenum (CoMo) species into the mesopores and micropores of NB-MOR, the NB-MOR-supported CoMo catalyst (CoMo/NB-MOR) exhibited an unprecedented high activity (99.1%) as well as very good catalyst life in the HDS of 4,6-dimethyldibenzothiophene compared with a conventional γ-alumina-supported CoMo catalyst (61.5%). The spillover hydrogen formed in the micropores migrates onto nearby active CoMo sites in the mesopores, which could be responsible for the great enhancement of the HDS activity.
    Journal of the American Chemical Society 07/2013; 135(31). DOI:10.1021/ja4043388 · 11.44 Impact Factor
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    ABSTRACT: Noble metal Pd and Pt catalysts with a wide range of surface wettability were fabricated through an electrochemical approach and were characterized with scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and atomic force microscopy. The importance of surface wettability of solid catalysts in multiphase reactions, especially their correlation to the nature of the studied chemical system, was investigated through reducing oxygen in an alkaline solution and oxidizing hydrogen peroxide and sodium formate in alkaline or buffered solutions at the as-prepared catalysts. These experiments illustrate that the nature of a multiphase reaction plays a critical role in determining the influence of surface wettability on the catalyst performance, providing a unique approach to decipher the reaction process. The investigation allows us to gain new insights into the electrochemical oxidation of sodium formate.
    ACS Applied Materials & Interfaces 04/2013; 5(9). DOI:10.1021/am4006918 · 5.90 Impact Factor
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    ABSTRACT: We fabricated the first superhydrophobic (SH) surface with microcavities, using a simple process. The process included an improved template method (ITM) for constructing the SH surface with cavities, using taro leaves as a pattern mask, and a dip-coating method for modifying the SH surface. The results obtained using the ITM are significantly better than those achieved using traditional template methods. In addition, the water-repellence of the microcavities surface was significantly enhanced by decorating with a layer of polymerized n-octadecylsiloxane nanosheets.
    Journal of Colloid and Interface Science 12/2012; 395. DOI:10.1016/j.jcis.2012.12.036 · 3.55 Impact Factor
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    ABSTRACT: Design and preparation of highly active hydrodesulfurization (HDS) catalysts is very important for the removal of air pollution. Herein, we report an extraordinarily active HDS catalyst, which is synthesized by loading of Pd on mesoporous zeolite Y (Pd/HY-M). The mesoporous zeolite Y is successfully synthesized using a water glass containing N,N-dimethyl-N-octadecyl-N-(3-triethoxysilylpropyl) ammonium [(C(2)H(5)O)(3)SiC(3)H(6)N(CH(3))(2)C(18)H(37)](+) cation as a mesoscale template. Compared with mesoporous Beta and ZSM-5 supported Pd catalysts (80.0% and 73.4% for Pd/HBeta-M and Pd/HZSM-5-M, respectively) as well as commercial catalyst of γ-Al(2)O(3) supported Pd catalyst (31.4%), Pd/HY-M catalyst exhibited very high activity in HDS of 4,6-dimethyldibenzothiophene (4,6-DM-DBT, 97.3%). The higher activity of Pd/HY-M than that of Pd/HBeta-M and Pd/HZSM-5-M is assigned to the larger micropore size of zeolite Y compared to that of Beta and ZSM-5. Theoretical simulation and adsorption experimental data show that 4,6-DM-DBT has difficulty entering the micropores of ZSM-5 and Beta zeolites, but the micropores of Y zeolite are accessible.
    Journal of the American Chemical Society 09/2011; 133(39):15346-9. DOI:10.1021/ja2072719 · 11.44 Impact Factor
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    ABSTRACT: Surfaces with superhydrophobicity are important in a number of biological and industrial processes. Hierarchical film based on polydimethylsiloxane (PDMS) and SiO2 with a water contact angle of 155° and sliding angle of 6° was prepared by a facile drop-coating method. Surface modification of SiO2 spheres was found to improve particle dispersion and increase their compatibility with PDMS, which eventually affected the stability of the hierarchical structure. Different curing temperatures were studied for enhancing the hydrophobicity of the hierarchical structure. We examined the mechanical robustness of the superhydrophobic surface by using a shear test, and found that the hierarchical PDMS-based SiO2 films retained superhydrophobicity after 48KPa mechanical shears.
    Surface and Coatings Technology 08/2011; 205(21):4910-4914. DOI:10.1016/j.surfcoat.2011.04.073 · 2.20 Impact Factor
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    ABSTRACT: A superhydrophobic polymerized n-octadecylsilane (PODS) surface with a highly ordered lamellar structure was obtained via a one-step solution immersion process. The PODS surface had water contact and sliding angles of 159° and ∼0°, respectively. A hydrophilic/superhydrophobic surface was then obtained by chemically bonding nano-SiO2 onto the PODS surface. This SiO2/PODS layer exhibited dew-enhancing ability, similar to that of the surface of the stenocara beetle. Vapor condensation occurring heterogeneously on the SiO2/PODS surface is proposed to explain the dew-enhancing property, and these hydrophilic/superhydrophobic surfaces may have applications in enhanced heat transfer.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 03/2011; 377(1):110-114. DOI:10.1016/j.colsurfa.2010.12.033 · 2.35 Impact Factor
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    ABSTRACT: This study develops a simple, rapid electrochemical approach for preparing dendrite-shaped Ag nanomaterials, which are well known as effective SERS substrates. In addition to yielding silver that exhibits a strong enhancement in SERS measurements when tested with 2,2′-dithiodipyridine and ethylenethiourea, this new fabrication method does not require any template, surfactants or supporting electrolyte, making it environment friendly. Analysis illustrates that the as-prepared Ag products are essentially pure silver consisting of abundant {111}-oriented crystallites. These Ag dendrites formed on a commercially available tin-doped indium oxide electrode could also be easily transferred onto other desired surfaces, making their application in SERS measurements more versatile.
    Green Chemistry 01/2011; 13(10). DOI:10.1039/C1GC15505A · 6.85 Impact Factor
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    ABSTRACT: The present paper describes the simple and low-cost process for the production of a superhydrophobic surface with micronano hierarchical structure from the chemisorptions of SiO(2) nanoparticles onto polymerized n-octadecylsilane. The process was carried out under ambient conditions without the use of expensive equipment. The as-prepared micronano-binary films exhibited a very high contact angle of 179.9 degrees and a low contact hysteresis of 2.5 degrees . On the basis of the results of the characterization techniques, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and contact angle (CA) measurements, a formation mechnism of the superhydrophobic micronano structure was proposed. Drop impact experiments on the modified-glass substrate showed that the as-prepared films possess a high-impalement threshold.
    ACS Applied Materials & Interfaces 08/2010; 2(8):2393-8. DOI:10.1021/am1004046 · 5.90 Impact Factor
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    ABSTRACT: A novel coordination polymer, [Ni(dppz)(oba)(H2O)]·0.5H2O (dppz = dipyrido[3,2-a:2′,3′-c]phenazine and oba = 4,4′-oxy(bisbenzoate)) has been synthesized through hydrothermal method and characterized by IR, and single-crystal X-ray diffraction. It crystallizes in monoclinic, space group C2/c with a = 23.163(5), b = 18.211(4), c = 14.460(3) Å, α = γ = 90°, β = 100.45(3)°, V = 5998(2) Å3, Z = 2. The structure was solved by direct methods and refined to R = 0.0866 (wR2 = 0.1836). The compound exhibits interesting one-dimensional chain structures, which are further stacked through π-π interactions to form supramolecular double chains. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
    Crystal Research and Technology 05/2009; 44(5):567 - 570. DOI:10.1002/crat.200900075 · 1.16 Impact Factor
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    ABSTRACT: Carboxylic-functionalized carbon nanofiber-supported Ru catalysts were prepared from the treatment of carbon nanofiber in HNO3–H2SO4 media, followed by impregnation with RuCl3 solution, dryness, calcination, and reduction procedures. Interestingly, carboxylic-functionalized carbon nanofiber-supported Ru catalysts show a good performance in oxidation of benzyl alcohol with molecular oxygen. In contrast, after partial removal of carboxylic groups on the surface of carbon nanofiber-supported Ru catalysts, the activities are reduced significantly. These results suggest that the carboxylic species on carbon nanofiber-supported Ru catalysts play an important role for the promotion of catalytic activity.
    Catalysis Letters 01/2009; 127(3):400-405. DOI:10.1007/s10562-008-9708-x · 2.29 Impact Factor
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    ABSTRACT: The activities of a Pd catalyst supported on mesoporous Beta zeolite (Beta-H) were evaluated for the hydrogenation of naphthalene and pyrene in the absence and presence of 200-ppm sulfur and for the hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT). Compared with Pd/Al-MCM-41, the Pd/Beta-H catalyst exhibited better sulfur tolerance for hydrogenation of naphthalene and pyrene and higher activity for HDS of 4,6-DMDBT. The ratio of the hydrogenation of the second ring naphthalene in the absence and presence of 200-ppm sulfur for Pd/Beta-H was larger than that for Pd/Al-MCM-41 (0.47 vs 0.19). The desulfurization effect of Pd/Beta-H was greater than that of Pd/Al-MCM-41 (51 vs 35%). The difference in sulfur tolerance and HDS ability of the 2 catalysts is attributed to the difference in support acidity. Beta-H exhibited more acidic sites and a higher percentage of strong acidic sites than Al-MCM-41 (552 μmol/g and 43% vs 291 μmol/g and 18%).
    Journal of Catalysis 07/2008; 257(1-257):125-133. DOI:10.1016/j.jcat.2008.04.013 · 6.07 Impact Factor
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    ABSTRACT: Palladium species were loaded into mesoporous Beta zeolite (Beta-H), and transmission electron microscopy images showed that the Pd particles are located in both mesopores and micropores. As a model reaction, the deep hydrogenation of bulky aromatic pyrene showed that the Pd/Beta-H catalyst exhibits higher activity than Pd/Beta, Pd/Al-MCM-41, and Pd/γ-Al2O3 catalysts. The superior performance of the Pd/Beta-H catalyst is attributed to its unique porous structure and acidity. The mesoporous volume in Beta-H (0.17 cm3/g) is greater than that of Beta (0.06 cm3/g), which is advantageous for adsorption and mass transport of pyrene over Pd/Beta-H catalyst. The amount of acidic sites is greater on Beta-H (480 μmol/g) than on Al-MCM-41 (280 μmol/g) and γ-Al2O3 (220 μmol/g), which also favors improved catalytic activity in hydrogenation of pyrene over Pd/Beta-H catalyst.
    Journal of Catalysis 07/2007; 249(1):111-115. DOI:10.1016/j.jcat.2007.03.031 · 6.07 Impact Factor
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    ABSTRACT: Introduction Zeolites with intricate micropores have been widely applied in industry at present, but the relatively small micropores in zeolites significantly influence the mass transport in many catalytic reactions. Recently, mesoporous zeolites from carbon templates have been successfully synthesized [1,2], but their industrial applications are still limited, because of the cost of template, the complexity of synthetic procedures, and the difficulty for dispersion of templates into gels. In this work, at first we describe templated synthesis of a series of hierarchically mesoporous zeolites such as Beta [3] and MFI from the use of mesoscale cationic polymers, then we investigate their catalytic properties in alkylation, cracking, hydrogenation [4], and hydrodesulfurization [5]. Experimental The samples of hierarchically mesoporous Beta (Beta-H) and mesoporous ZSM-5 (ZSM-5-H) were hydrothermally synthesized from a mixture template of tetraethylammonium hydroxide (TEAOH) and tetrapropylammonium hydroxide (TPAOH) with cationic polymer at 140 °C and 180 °C, respectively. H-form of samples was ion-exchanged twice with NH 4 NO 3 solution (1M) at 70 °C for 3 h, followed by calcination at 500 °C for 4 h. Zeolite-supported palladium catalysts were prepared by ion-exchange with [Pd(NH 3) 4 ] 2+ solution, followed by calcination and reduction procedures. The alkylation of benzene with isopropanol was carried out at a reaction temperature of 200 ºC with benzene/isopropanol molar ratio of 4/1, reaction pressure of 2.0 MP, and WHSV of 10 h -1 ; Cracking of bulky 1,3,5-triisopropylbenzene was performed at 300 °C by pulse injections (0.4 μl) with 50 mg of catalyst; Pyrene hydrogenation was carried out in an autoclave at a temperature of 250 °C, hydrogen pressure of 40 bar, and 3.5 g of pyrene in 120 mL of tridecane; Hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT, 0.2 g) was carried out using tridecane (110 mL) as solvent with a catalyst amount of 300 mg, total pressure of 65 bar, and 250 °C Results and Discussion The X-ray diffraction (XRD) patterns of mesoporous zeolites templated from cationic polymer templates show characteristic peaks associated with zeolites such as Beta and ZSM-5. Furthermore, nitrogen isotherms of these samples exhibits pore size distribution ranged from 4-40 nm, indicating the presence of mesoporosity in these samples. Interestingly, both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques confirm the presence of mesoporosity in these samples. When palladium species are loaded into mesoporous Beta zeolite (Beta-H), TEM images show that Pd particles are located in both mesopores and micropores. The presence of mesoporosity in these zeolites is favorable for the catalytic conversion of bulky molecules and the mass transport in catalysis.