Large-pore phenyl-bridged periodic mesoporous organosilicas (PMOs) were facilely synthesized by evaporation-induced self-assembly of 1,4-bis(triethoxysily)benzene and triblock copolymer Pluronic F127 as a template under acid conditions combined with a mixed-solvothermal treatment. The ordered PMOs exhibit large uniform mesopores of ∼9.9nm in diameter after calcination at 350°C in a nitrogen atmosphere. The mesoporous phenyl-bridged organosilica products have an ordered hexagonal mesostructure with space group p6mm. N₂ adsorption/desorption isotherms reveal imperfect mesopore channels with high surface areas (up to 1150m²/g) and thick pore walls (up to 7.7nm). The mesopores can be expanded with the decrease of acidity, as well as the increase of Pluronic F127 content. A mixed-solvothermal treatment in N,N-dimethylformamide (DMF) and water at 100°C was first used to improve the periodicity of the mesopore walls, as well as increase the wall thickness. The composites exhibit efficient adsorption capacities (2.06mmolg^-1) for benzene, suggesting a potential adsorbent for removal of volatile organic compounds. The EISA approach combined with the mixed-solvothermal treatment provides important insights into the development of large-pore PMOs by using long-chain organosilanes, and further demonstrates the ability to fabricate materials with thick walls.

Na Hao;Yunxia Yang;Huanting Wang;Paul A. Webley;东元 赵

Journal of Colloid and Interface Science

2010-6

This work investigates the possibility of using LaMn _0.7Fe _0.3O _3.15@mSiO ₂ as oxygen carriers for chemical looping combustion (CLC). CLC is a new combustion technique with inherent separation of CO ₂ from atmospheric N ₂. LaMn _0.7Fe _0.3O _3.15@mSiO ₂ core-shell materials were prepared by coating a layer of mesostructured silica around the agglomerated perovskite particles. The oxygen carriers were characterized using different methods, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N ₂ sorption, hydrogen temperature-programmed reduction (H ₂-TPR), and temperature- programmed desorption of oxygen (TPD-O ₂). The reactivity and stability of the carrier materials were tested in a special reactor, allowing for short contact time between the fluidized carrier and the reactive gas [Chemical Reactor Engineering Centre (CREC) fluidized riser simulator]. Multiple reduction-oxidation cycles were performed. TEM images of the carriers showed that a perfect mesoporous silica layer was formed around samples with 4, 32, and 55 nm in thickness. The oxygen carriers having a core-shell structure showed higher reactivity and stability during 10 repeated redox cycles compared to the LaMn _0.7Fe _0.3O _3.15 core. This could be due to a protective role of the silica shell against sintering of the particles during repeated cycles under CLC conditions. The agglomeration of the particles, which occurred at high temperatures during CLC cycles, is more controllable in the core-shell-structured carriers, as confirmed by SEM images. XRD patterns confirmed that the crystal structure of all perovskites remained unchanged after multiple redox cycles. Methane conversion and partial conversion to CO ₂ were observed to increase with the contact time between methane and the carrier. Indeed, more oxygen from the carrier surface, grain boundaries, and even from the bulk lattice was released to react with methane. Upon rising the contact time, less CO was formed, which is desirable for CLC application. Increasing the reaction temperature and methane partial pressure lead to enhanced conversions of CH ₄ under CLC conditions.

Zahra Sarshar;Zhenkun Sun;东元 赵;Serge Kaliaguine

Energy & Fuels

2012-5-17

Highly ordered hexagonal mesoporous aluminosilicates (MAS-5) with uniform pore sizes have been successfully synthesized from assembly of preformed aluminosilcate precursors with cetyltrimethylammonium bromide (CTAB) surfactant. The aluminosilicate precursors were obtained by heating, at 100-140 °C for 2-10 h, aluminasilica gels at the Al₂O₃/SiO₂/TEAOH/H₂O molar ratios of 1.0/7.0-350/10.0-33.0/500-2000. Mesoporous MAS-5 shows extraordinary stability both in boiling water (over 300 h) and in steam (800 °C for 2 h). Temperature-programmed desorption of ammonia shows that the acidic strength of MAS-5 is much higher than that of MCM-41 and is comparable to that of microporous Beta zeolite. In catalytic cracking of 1,3,5-triisopropylbenzene and alkylation of isobutane with butene, MAS-5 exhibits greater catalytic activity and selectivity, as compared with MCM-41 and HZSM-5. The MAS-5 samples were characterized with infrared, UV-Raman, and NMR spectroscopy and numerous other techniques. The results suggest that MAS-5 consists of both mesopores and micropores and that the pore walls of MAS-5 contain primary and secondary structural building units, similar to those of microporous zeolites. Such unique structural features might be responsible for the observed strong acidity and high thermal stability of the mesoporous aluminosilicates with well-ordered hexagonal symmetry.

Z. Zhang;Y. Han;丰收 肖;式纶 裘;L. Zhu;R. Wang;Y. Yu;Z. Zhang;B. Zou;Y. Wang;H. Sun;东元 赵;岩 危

Journal of the American Chemical Society

2001

Single-layered two-dimensional (2D) ultrathin mesoporous polymer/carbon films are grown by self-assembly of monomicelles at the interfaces of various substrates, which is a general and common modification strategy. These unconventional 2D mesoporous films possess only a single layer of mesopores, while the size of the thin films can grow up to inch size in the plane. Free-standing transparent mesoporous carbon ultrathin films, together with the ordered mesoporous structure on the substrates of different compositions (e.g. metal oxides, carbon) and morphologies (e.g. nanocubes, nanodiscs, flexible and patterned substrates) have been obtained. This strategy not only affords controllable hierarchical porous nanostructures, but also appends the easily modified and multifunctional properties of carbon to the primary substrate. By using this method, we have fabricated Fe₂O₃-mesoporous carbon photoelectrochemical biosensors, which show excellent sensitivity and selectivity for glutathione.

Yin Fang;Yingying Lv;Jing Tang;Hao Wu;Dingsi Jia;Dan Feng;Biao Kong;Yongcheng Wang;Ahmed A. Elzatahry;Daifallah Al-Dahyan;Qichun Zhang;耿锋 郑;东元 赵

Angewandte Chemie - International Edition

2015-7-13

Bozhi Tian;Xiaoying Liu;波 屠;承忠 余;杰 范;Limin Wang;Songhai Xie;Galem D. Stucky;东元 赵

Nature Materials

2003-3

Rapid and deep self-reconstruction (SELF-RECON) was achieved through rational design of the precatalyst. The obtained core-shell nanowired precatalyst (NiMoFeO@NC) consists of NiMoO₄ nanoparticles (core) and NiFe/NiFeO_x nanoparticles in N-doped carbons (shell). The SELF-RECON process was facilitated by rapid MoO₄²⁻ dissolution in the core of NiMoFeO@NC and fast formation of NiOOH with Fe incorporation simultaneously, which was monitored and demonstrated by in situ Raman experiments. The obtained SELF-RECONCAT outperforms NiMoFeO@NC, with ultralow overpotentials and extraordinary long-term stability.

Yang Wang;Yinlong Zhu;Shenlong Zhao;Sixuan She;Feifei Zhang;Yu Chen;Timothy Williams;Thomas Gengenbach;Lianhai Zu;Haiyan Mao;Wei Zhou;宗平 邵;Huanting Wang;Jing Tang;东元 赵;Cordelia Selomulya

Matter

2020

Core–shell magnetic porous microspheres have wide applications in drug delivery, catalysis and bioseparation, and so on. However, it is great challenge to controllably synthesize magnetic porous microspheres with uniform well-aligned accessible large mesopores (>10 nm) which are highly desired for applications involving immobilization or adsorption of large guest molecules or nanoobjects. In this study, a facile and general amphiphilic block copolymer directed interfacial coassembly strategy is developed to synthesize core–shell magnetic mesoporous microspheres with a monolayer of mesoporous shell of different composition (FDUcs-17D), such as core–shell magnetic mesoporous aluminosilicate (CS-MMAS), silica (CS-MMS), and zirconia-silica (CS-MMZS), open and large pores by employing polystyrene-block-poly (4-vinylpyridine) (PS-b-P4VP) as an interface structure directing agent and aluminum acetylacetonate (Al(acac)₃), zirconium acetylacetonate, and tetraethyl orthosilicate as shell precursors. The obtained CS-MMAS microspheres possess magnetic core, perpendicular mesopores (20–32 nm) in the shell, high surface area (244.7 m² g⁻¹), and abundant acid sites (0.44 mmol g⁻¹), and as a result, they exhibit superior performance in removal of organophosphorus pesticides (fenthion) with a fast adsorption dynamics and high adsorption capacity. CS-MMAS microspheres loaded with Au nanoparticles (≈3.5 nm) behavior as a highly active heterogeneous nanocatalyst for N-alkylation reaction for producing N-phenylbenzylamine with a selectivity and yields of over 90% and good magnetic recyclability.

Yu Zhang;Qin Yue;Lei Yu;Xuanyu Yang;Xiu Feng Hou;东元 赵;Xiaowei Cheng;勇辉 邓

Advanced Materials

2018-6-27

Highly ordered mesoporous platinum@graphitic carbon (Pt@GC) composites with well-graphitized carbon frameworks and uniformly dispersed Pt nanoparticles embedded within the carbon pore walls have been rationally designed and synthesized. In this facile method, ordered mesoporous silica impregnated with a variable amount of Pt precursor is adopted as the hard template, followed by carbon deposition through a chemical vapor deposition (CVD) process with methane as a carbon precursor. During the CVD process, in situ reduction of Pt precursor, deposition of carbon, and graphitization can be integrated into a single step. The mesostructure, porosity and Pt content in the final mesoporous Pt@GC composites can be conveniently adjusted over a wide range by controlling the initial loading amount of Pt precursor and the CVD temperature and duration. The integration of high surface area, regular mesopores, graphitic nature of the carbon walls as well as highly dispersed and spatially embedded Pt nanoparticles in the mesoporous Pt@GC composites make them excellent as highly active, extremely stable, and methanol-tolerant electrocatalysts toward the oxygen reduction reaction (ORR). A systematic study by comparing the ORR performance among several carbon supported Pt electrocatalysts suggests the overwhelmingly better performance of the mesoporous Pt@GC composites. The structural, textural, and framework properties of the mesoporous Pt@GC composites are extensively studied and strongly related to their excellent ORR performance. These materials are highly promising for fuel cell applications and the synthesis method is quite applicable for constructing mesoporous graphitized carbon materials with various embedded nanophases.

Zhangxiong Wu;Yingying Lv;永姚 夏;Paul A. Webley;东元 赵

Journal of the American Chemical Society

2012-2-1

A new two-dimensional microporous metal-organic framework Cu(BDC-OH)(H ₂O).0.5DEF [abbreviation: Cu(BDCOH); H₂BDC-OH = 2-hydroxybenzene-1,4-dicarboxylic acid; DEF = diethylformamide] with functional OH groups on the pore surfaces was solvothermally synthesized and structur-ally characterized. The activated Cu(BDC-OH) exhibits a moderate Langmuir surface of 584 m²g^-1, a pore volume of 0.214 cm³g ^-1, and C₂H₂/CH₄ and CO ₂/CH₄ selectivity of 6.7 and 9.3, respectively, at 296 K, thereby highlighting the promise for its application in gas separation.

Zhenxia Chen;生昌 项;Hadi D. Arman;Peng Li;Steven Tidrow;东元 赵;Banglin Chen

European Journal of Inorganic Chemistry

2010-8

Mesoporous silica SBA-15 was functionalized by 2-diethylamino-ethanol (DEAE) through the epoxide ring opening of 3-glycidyloxy-propyl-trimethoxy silane grafted on the silica surface (denoted as DEAE-SBA-15). Subsequently, DEAE-SBA-15 was used as the weak anion exchange matrix for chromatography to purify Der f 2 allergen from the spent culture medium extract of Dermatophagoides farinae, one of House dust mites that can cause heavy atopic diseases such as asthma and dermatitis. The structure of DEAE-SBA-15 was confirmed by ¹³C and ²⁹Si CP MAS NMR and other methods. By SDS-PAGE, Der f 2 was estimated to have a molecular weight of 14000 and appeared as the only separated protein band. The assay results of skin prick test showed that the allergic activity of Der f 2 was retained. The above results indicate that DEAE-SBA-15 materials are promising fixed-matrix candidates in liquid chromatography to purify proteins.

Jie Lei;Lu Yan Zhang;Sheng Song Ding;Shi Yi Jiang;承忠 余;东元 赵

Kao Teng Hsueh Hsiao Hua Heush Hsueh Pao/ Chemical Journal of Chinese Universities

2005-5