Tianbo Zhao

Beijing Institute Of Technology, Peping, Beijing, China

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Publications (21)24.42 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The main objective of this study was to develop an easy method, based on the hydrogen-bonding interaction between a polymer network and a sucrose solution, for fabricating bulk nanostructured carbon materials. In this study, bulk nanostructured carbon materials were synthesized by using the superabsorbent polymers with multiple networks, prepared in advance, as templates and sucrose as a carbon precursor. The synthesis scheme consisted of preparing the multiple polymer networks, saturating it with sucrose solution and carbonizing the sucrose solution. The above procedure leads to the carbon materials with a variety of new morphologies: leaves-like carbon sheets, carbon clusters, carbon sticks and spherical carbons. This synthesis scheme allowed the fabrication of bulk nanostructured carbon materials, and a mechanism for their formation is proposed.
    Materials Chemistry and Physics. 08/2012; 135(s 2–3):668–675.
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    ABSTRACT: A method for routine determination of fluorine, chlorine and bromine in household products was developed and validated. In this work, halogen analyses were made based on oxygen bomb combustion followed by ion chromatography (IC). The chromatographic analysis was performed by an IonPac AS19 hydroxide-selective anion-exchange column, a reagent free ion chromatograph eluent generator and an anion self-regenerating suppressor in 10 min. The response was linear (r ≥ 0.9995) in the entire investigated domain. The limit of detection for the halogens was in the range of 2 to 9 × 10(-3) mg/L and the limit of quantification was lower than 8 mg/Kg with 20 µL of injection volume. The certified reference material of ERM-EC 681k was pretreated using an oxygen bomb combustion procedure to demonstrate the precision of the proposed method. The quantitative analysis results obtained by IC for the target elements were 797 ± 9 mg/Kg chlorine and 786 ± 25 mg/Kg bromine, which were in good agreement with the certified values of 800 ± 4 mg/Kg chlorine, 770 ± 5 mg/Kg bromine for ERM-EC 681k, respectively. This validated method was successfully applied for the analysis of fluorine, chlorine and bromine in household product samples, and the variation of halogen contained among the tested samples was remarkable..
    Journal of chromatographic science 06/2012; · 0.79 Impact Factor
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    ABSTRACT: AbstractA novel micro-micro/mesoporous silicoaluminophosphate ZSM-5-SAPO-5/MCM-41 (define as MZS-5) composite material with regular spherical morphology was synthesized through a novel process of the self-assembly of CTAB surfactant micelles with silica-alumina source which originated from the alkaline treatment of ZSM-5 zeolite. The physical properties of the MZS-5 composite material were characterized by XRD, FT-IR, Nitrogen adsorption–desorption, SEM and Py-FTIR techniques. Catalytic tests showed that the MZS-5 composite catalyst exhibited higher catalytic activity compared with the conventional microporous ZSM-5, SAPO-5 zeolite and mesoporous Al-MCM-41 molecular sieve for catalytic cracking of 1,3,5-triisopropylbenzene (TIPB). The remarkable catalytic reactivity of TIPB molecules was mainly attributed to the presence of the hierarchical zeolite structure. In the MZS-5 structure, the mesopores provided pathways for transportation of larger molecules and the microporous ZSM-5 and SAPO-5 zeolite provided acidic sites for catalytic activity. Graphical AbstractA novel micro-micro/mesoporous silicoaluminophosphates MZS-5 catalyst exhibited higher catalytic activity than microporous ZSM-5, SAPO-5 and mesoporous Al-MCM-41 for catalytic cracking of 1,3,5-triisopropylbenzene due to its hierarchical porosity. KeywordsMicro-micro/mesoporous–Silicoaluminophosphate–Catalytic cracking–1,3,5-Triisopropylbenzene
    Journal of Porous Materials 01/2011; 18(1):69-81. · 1.35 Impact Factor
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    ABSTRACT: An easy method is described for fabricating carbon sheets with nanostructures using sucrose as a carbon precursor and a layered superabsorbent polymer (LSAP) as a structure-directing agent. The method is based on the interaction of the three-dimensional polymer networks of the LSAP with a sucrose solution in the hydrogel cells. The synthesis scheme consists of: (a) preparation of the LSAP, (b) preparation of layered hydrogels by immersing the LSAP in the sucrose solution for 2days, (c) carbonization of the layered hydrogels containing the sucrose solution. The synthesized carbon sheets show different microstructures including petal-like, regular and interleaved types, which can be controlled by simply adjusting the initial concentration of the sucrose solution in the hydrogel cells. Moreover, a formation mechanism for the carbon sheets is proposed.
    Carbon. 01/2011; 49(2):357-363.
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    ABSTRACT: The objective of this work was to evaluate the use of hydrothermal method for the synthesis of small and homogeneous silicalite-1 zeolite. The influences of crystallization time, crystallization temperature, different organic solvents and different TPAOH template concentrations were investigated. The results showed these parameters had played important roles in controlling particle size of silicalite-1 zeolite.
    Journal of Porous Materials 01/2011; 18(4):509-515. · 1.35 Impact Factor
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    ABSTRACT: Three methods were developed for analysis of benzene, toluene, p-xylene, m-xylene and o-xylene (BTX) in a solid-liquid mixing paint. These methods were based on solid phase extraction-thermal desorption-gas chromatography with a flame ionization detector (SPE-TD-GC-FID), ultra performance liquid chromatography-photodiode array detector (UPLC-PDA) and gas chromatography-mass spectrometry (GC-MS). At their optimum conditions of operation, the developed methods were compared in terms of recovery, sensitivity, selectivity and universality. Although the time required for GC-MS analysis was shorter than for GC-FID and UPLC-PDA, it offered relatively poorer recoveries and suffered from matrix interferences. All of the mentioned methods were proven to be ideal for the analysis of targeted analytes; SPE-TD-GC-FID was particularly fit for the determination of trace level BTX residues present in the complex matrix. As one of the sample pretreatment techniques, the novel SPE also showed some selectivity towards BTX and was found to be superior to the conventional SPE.
    Chromatographia 01/2011; 74(1):163-169. · 1.44 Impact Factor
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    ABSTRACT: A novel method was developed and validated for determination of benzene, toluene, p-xylene, m-xylene, o-xylene (BTEX) in a solid–liquid mixing matrix. It makes use of solid phase extraction and thermal desorption (SPE-TD), followed by gas chromatographic flame ionization detector analysis (GC-FID). The trapped BTEX can be measured directly after thermal desorption onto the stainless-steel packed chromatographic column. The effect of tailing area of solvent was removed with the use of SPE-TD technique, and the result shows good reproducibility with very little matrix dependency. The study also supports that the lifetime of the Tenax adsorption tube could be extended over 150 desorption operation at 200°C, which enables performing excellent stability and reproducibility of BTEX analysis. KeywordsGas chromatography-Solid phase extraction and thermal desorption-Stainless-steel packed chromatographic column-BTEX in painting materials
    Chromatographia 01/2010; 71(11):1131-1135. · 1.44 Impact Factor
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    ABSTRACT: A novel micro-mesoporous silicoaluminophosphate (MUS-5) with controlled morphology has been first synthesized in a two-step route. The physical properties of the silicoaluminophosphate were characterized using XRD, SEM, TEM, nitrogen adsorption-desorption and NH3-TPD techniques. When the pH value of the solution system was varied in the range from 2.0 to 5.0, three different morphologies of silicoaluminophosphate including chain-like, flower-like and barrel-like morphology were obtained. Catalytic tests showed that the silicoaluminophosphate exhibited higher catalytic activity compared with the conventional microporous SAPO-5 under the same conditions for catalytic cracking of 1,3,5-triisopropylbenzene heavy aromatics. The remarkable catalytic reactivity was mainly attributed to the presence of the hierarchical porosity in the silicoaluminophosphate catalyst.
    Science China-Chemistry 01/2010; 53(11):2279-2284. · 1.33 Impact Factor
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    ABSTRACT: A new type meso-ZSM-5 composite zeolite with interconnected macropores and skeletons under hydrothermal conditions was prepared through zeolite degraded method. The skeletons can be templated to the morphology of network in different conditions. The physical properties of the meso-ZSM-5 composite zeolite were characterized by XRD, IR, SEM and nitrogen sorption techniques. Catalytic tests show that the meso-ZSM-5 composite zeolite catalyst exhibits high catalytic activity compared with the conventional microporous ZSM-5 zeolites for catalytic cracking of 1,3,5-triisopropylbenzene. The high 1,3,5-triisopropylbenzene conversion are mainly assigned to the presence of the hierarchical porosity of the pore walls. The macropores offer easier transport and access to the active sites and the macroporous walls built by ZSM-5 crystals provide the acidic sites for reaction. KeywordsMeso-ZSM-5-Network structure-Cracking-1,3,5-triisopropylbenzene
    Journal of Porous Materials 01/2010; 17(2):177-184. · 1.35 Impact Factor
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    ABSTRACT: Novel hierarchical zeolites with continuous micrometer-scale macropores and mesopores other than popular nanometer-scale mesopores and micropores were synthesized by transforming the skeletons of the silica monolith into zeolites through both the steam-assisted conversion and nanocasting methods. Results showed the novel hierarchical zeolites exhibited high catalytic activity for catalytic cracking large molecules. KeywordsHierarchical zeolites-Catalytic cracking
    Catalysis Letters 01/2010; 136(3):266-270. · 2.24 Impact Factor
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    ABSTRACT: Macroporous silica–alumina composites with continuous micrometer-scale pores were synthesized by seed-induced vapor-phase transport treatment. The parent silica–alumina monolith was employed as the silica and alumina source as well as the template for the three-dimensional interconnected structure. The silicalite-1 precursor solution with dispersed zeolite seeds was drawn into the pore channels of the parent monolith for modification by in-situ and layer-by-layer methods before the hydrothermal crystallization, which was believed to play a significant inducing role in the zeolite growing process. The composites synthesized are expected to display high catalytic performance on the bulky molecules since they incorporate the strong acidic advantages of the microporous zeolite and the macroporous pathways of the monolithic skeletons for mass transport.
    Materials Letters - MATER LETT. 01/2010; 64(15):1660-1663.
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    ABSTRACT: A novel mesoporous beta with interconnected macropores and skeletons under hydrothermal conditions was prepared through zeolite degraded method. The skeletons can be templated to the morphology of network in different conditions. The physical properties of the mesoporous beta were characterized by XRD, SEM and nitrogen sorption techniques. Catalytic tests show that the mesoporous beta catalyst exhibits high catalytic activity compared with the conventional microporous beta zeolites for catalytic cracking of 1,3,5-triisopropylbenzene. The high 1,3,5-triisopropylbenzene conversion are mainly assigned to the presence of the hierarchical porosity of the pore walls.
    Catalysis Communications - CATAL COMMUN. 01/2009; 10(11):1523-1528.
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    ABSTRACT: Zeolite beta monoliths with hierarchical porosity were prepared by the steam-assisted conversion of pre-seeded bimodal pore silica gel using the Layer-by-Layer process. The bimodal pore silica gel acts as both macrotemplates and silica source. The zeolite beta monoliths were characterized by X-ray diffraction, scanning electron microscopy, IR absorption spectra and nitrogen adsorption measurements. This zeolite beta monolith had hierarchical porosity: the unique micropores within the zeolite, the small macropores generated by aggregation of crystallites and three dimensionally interconnected macropores formed by template of silica gel. It is believed that the hierarchical structured zeolite monoliths will show good properties and potential applications the fields of catalyst, ion exchange, and adsorption.
    Journal of Porous Materials 11/2008; 15(6):643-646. · 1.35 Impact Factor
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    ABSTRACT: Cu/SiO2 catalyst with bimodal pore structure was prepared by co-gelation reactions of tetramethoxysilane (TMOS) and copper nitrate in the presence of poly (ethylene oxide) (PEO) with an average molecular weight of 10,000 and the catalyst of acetic acid. In this process, the interconnected macroporous morphology was formed when transitional structures of spinodal decomposition were frozen by the sol–gel transition of silica. The addition of copper into the silica–PEO system had a negligible effect on the morphology formation. In gel formation, it was found that the crystallite sizes of the CuO estimated from the peak width in the Cu/SiO2 with the presence of PEO were not small as expected. It was considered that there was no obvious interaction between the Cu cation and PEO, most of the copper ions in wet silica gel were present in the outer solution. They easily aggregated as copper salts in the drying process of wet gel and decomposed into CuO particles in heating. While in the Cu/SiO2 with the absence of PEO, the Cu was selectively entrapped as small particles in the gel skeleton due to the interaction between Cu aqua complex and silica gel network.
    Journal of Materials Science 01/2007; 42(19):8320-8325. · 2.31 Impact Factor
  • Chemistry of Materials - CHEM MATER. 08/2006; 18(18).
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    ABSTRACT: A hierarchical zeolite catalyst was synthesized by transforming the skeletons of a bimodal pore silica gel into a zeolite through a steam-assisted conversion method, and shows high catalytic activity and a long catalyst lifetime for catalytic cracking of large molecules.
    Chemical Communications 05/2006; · 6.38 Impact Factor
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    ABSTRACT: CuO/SiO2 and NiO/SiO2 with bimodal pore structure were prepared by sol-gel reactions of Tetra-methoxysilane (TMOS) and the respective metal nitrate in the presence of poly (ethylene oxide) (PEO) with an average molecular weight of 10 000 and the catalyst of acetic acid. In this process, the interconnected macroporous morphology was formed when transitional structures of spinodal decomposition were frozen by the sol-gel transition of silica. The addition of copper and nickel into the silica-PEO system had a negligible effect on the morphology formation. In gel formation, it was found that NiO crystalline sizes in the samples increased with decreasing Si/Ni molar ratio. It was considered that PEO interacted with both silica and nickel cations. In the CuO/SiO2 with the presence of PEO, CuO crystalline sizes were larger than those of NiO/SiO2. It was considered that there was no obvious interaction between the Cu cation and PEO, most of the copper ions in wet silica gel were present in the outer solution. They easily aggregated as copper salts in the drying process of wet gel and decomposed into CuO particles in heating. While in the CuO/SiO2 with the absence of PEO, the Cu was selectively entrapped as small particles in the gel skeleton due to the interaction between Cu aqua complex and silica gel network.
    Journal of Sol-Gel Science and Technology 01/2006; 39(2). · 1.66 Impact Factor
  • Chemistry Letters - CHEM LETT. 01/2006; 35(5):490-491.
  • Chemistry Letters - CHEM LETT. 01/2006; 35(7):702-703.
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    ABSTRACT: An efficient and reliable technique to evaluate the degree of coverage of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was described. The method was based on a quantitative analysis of RDX leakage carried out with a high performance of liquid chromatography (HPLC). For this study, replicated analyses were performed on coated samples prepared by different kinds of coating materials and methods. The efficiency of characterization by using both HPLC and scanning electron microscope was compared. To note, the evaluation through former technique is more on macroscopic perspective rather than morphological observation of sample. Meanwhile, the HPLC method also provided characterization results that were in good agreement with morphology observation. A noteworthy advantage of this original technique is that the evaluation of coating quality of melt-cast explosives can be carried out under similar conditions. The experimental data were provided for deep understanding of the soluble behavior of coated RDX and its possible applications in practical problems.
    Chromatographia 75(19-20). · 1.44 Impact Factor