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Bismuth Modified porous silica Preparation,Characterization and Photocatalytic Activity Evaluation for Degradation of Isoproturon

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Journal of Materials Science & Technology 2013年第7期29卷 639-646页

作者： Anil Kumar Reddy Police Srinivas Basavaraju Durga Kumari Valluri Subrahmanyam Machiraju Inorganic and Physical Chemistry Division Indian Institute of Chemical TechnologyHyderabad 500607India

porous silica prepared by using an acrylic emulsion has been impregnated with bismuth ion resulting in Bi2Si05 species containing surface. The as-prepared materials have been characterized by X-ray diffraction spectroscopy （XRD）, X-ray photoelectron spectroscopy （XPS）, UV-Vis diffuse reflectance spectroscopy （UV-Vis DRS）, scanning electron microscopy （SEM）, energy dispersive analysis of X-ray （EDAX）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FTIR） and N2 adsorption/desorption techniques. EDAX analysis confirms the penetration of bismuth ions into the framework of silica to form Bi2SiO5, which is substantiated by XRD. The UV-Vis DRS shows that the catalysts are optically active and XPS confirms the inclusion of bismuth into the framework of silica. FTIR spectra illustrate the formation of Bi-O-Si linkages in the porous silica framework. SEM and TEM show the spherical morphology, whereas N2 adsorption/desorption study confirms the porosity of the prepared materials. The photocatalytic activity of the material is evaluated for the degradation of isoproturon herbicide and it is found that the material is active as compared to the commercial P-25 Degussa TiO2.

关键词： Acrylic emulsion Emulsion polymerization technique porous silica Bi2SiO5 Photocatalyfic degradation lsoproturon

Micromechanical interlocking-inspired dendritic porous silicabased multimodal resin composites for the tooth restoration

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Nano Research 2024年第10期17卷 9065-9077页

作者： Hongyan Chen Junjun Wang Shi Yin Ruili Wang Xinquan Jiang Meifang Zhu State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Material Science and EngineeringDonghua UniversityShanghai 201620China Shanghai Engineering Research Center of Advanced Dental Technology and Materials Shanghai Key Laboratory of StomatologyShanghai Research Institute of StomatologyNational Clinical Research Center for Oral DiseasesShanghai Ninth People’s HospitalCollege of StomatologyShanghai Jiao Tong University School of MedicineShanghai 200011China

porous silica particles have shown great potential application as reinforcing fillers in the field of dentistry due to their ability to construct the micromechanical interlocking effect at filler-matrix ***,how to accurately regulate the pore structure,especially the pore size,to increase the degree of the micromechanical interlocking and the performance of materials remains a ***,we have proposed a facile self-assembly process to synthesize dendritic porous silica with tunable pore sizes(DPS-x)by adjusting the chain-length of the alcohols in the *** mechanism of nucleation-growth is further put *** results indicate that the pore size of DPS-x indeed affects the mechanical property of composites,where the DPSpen particles with intermediate pore size are chosen as the optimal reinforcing *** bimodal and multimodal filler formulations are further established to address the loading limitation of unimodal DPS-pen(46 wt.%).In virtue of the closepacked structure of identical spheres,the particle sizes of secondary silica embedded into the maximally loaded bimodal D3S7 composite(DPS-pen:Si430=30:70,w/w)are theoretically calculated without *** all formulations,the developed multimodal D3S7+Si178+Si90 filler exhibits superior mechanical properties,the lowest shrinkage,and high polymerization conversion for dental composites,along with satisfied waster sorption and solubility,and good biocompatibility in vitro and in vivo,which are comparable to commercial composite Z350 XT(3M,USA).These DPS-x particles and their multimodal fillers can also be applied to other polymer-based biomaterials.

关键词： porous silica pore size multimodal filler dental composite physicochemical properties biosafety

Structrue and Characteristics of Mesoporous silica Synthesized in Acid Medium and Its Reaction Mechanism

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Journal of Wuhan University of Technology(Materials Science) 2004年第3期19卷 58-61页

作者：雷家珩 Wuhan University of Technology

Structrue and pore characteristics of the mesoporous silica synthesized in acid medium were studied by means of XRD, HRTEM, BET, FT-IR, DSC-TGA, and the reaction mechanism was also investigated deeply. The results show that mesopores in the sample possess hexagonal arrays obviously, whereas the structure of silica matrix is amorphous. The results also show that the acting mode of silica and CTMA+ inside the mesopores was chemical bonding force. The structure of mesoporous silica was mainly dependent on the aggregational condition of micelle of CTMA+ as well as their liquid-crystallized status. In addition, condensation and dehydration of silicate radicals were accompanied in the process of calcination, which resulted in the mesoporous structure ordered in local range and the pore sizes largening.

关键词： porous silica mesoporous molecular sieves isothermal adsorption CTMABr

Synthesis of amine-pillar[5]arene porous adsorbent for adsorption of CO_(2)and selectivity over N_(2)and CH_(4)

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Chinese Chemical Letters 2024年第11期35卷 226-231页

作者： Hui Li Yanxing Qi Jia Chen Juanjuan Wang Min Yang Hongdeng Qiu CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China National Engineering Research Center for Fine Petrochemical Intermediates Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

A novel amine-modified pillar[5]arene bonded porous silica adsorbent(DETA-P5S)was designed to be applied to dynamic CO_(2)adsorption and selective separation of CO_(2)over N_(2)and CH_(4)gases *** results demonstrated that reasonable introduction of DETA into the BE-P5 bonded silica support has sig nificantly increased the adsorption capacity of CO_(2).The DETA-P5S has the optimal adsorption capacity of 9.1 mmol/g with 5 vol%CO_(2)at 40℃.The main reason of this increased capacity could be attributed to the enhanced CO_(2)diffusion into porous adsorbent for its better dispersion in the pores of amine pillar[5]arene cavity and active site of ***,the dynamic saturation adsorption capacitie of DETA-P5S were 7.11(0.37)and 6.18(0.44)mmol/g for CO_(2)/N_(2)and CO_(2)/CH_(4),respectively,both the ga mixtures showed high separation ***,the DETA-P5S can maintain outstanding CO_(2)adsorption capacity after fifteen regeneration ***,the designed DETA-P5S could serve a a promising adsorbent for CO_(2)capture and storage.

关键词： CO_(2)adsorption Selective separation porous silica Solid amine adsorbents Amine-pillararene

Single-step thermal carburization synthesis of supported molybdenum carbides from molybdenum-containing methyl-silica

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Journal of Natural Gas Chemistry 2011年第3期20卷 271-280页

作者： Juan Zou Minglin Xiang Bo How Dong Wu Yuhan Sun Hunan Changling Petrochemical S＆T Developing Co. Ltd. Yueyang 414012 Hunan China State Key Laboratory of Coal Conversion Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan 030001 Shanxi China

A novel synthesis route to obtain highly dispersed molybdenum carbides in porous silica is described. The synthesis was carried out by a single-step heat treatment of molybdenum-containing and methyl-modified silica （Mo-M-SiO2） in argon atmosphere at 973 K. Mo-M-SiO2 precursor was facilely obtained via a one-pot synthesis route, using （NH4）6Mo7O24 4H2O （AHM） as molybdenum sources and polymethylhydrosiloxane （PMHS） as silica sources at the initial synthetic step. The optimal C/Mo molar ratio in reaction system for complete carburization of molybdenum species was 7. The carburization process of molybdenum species followed a nontopotactic route involving a MoO2 intermediate phase, which was evidenced by XRD, N2 adsorption-desorption and in situ XPS. Formation mechanism of Mo-M-SiO2 precursor was also proposed by observation of the reaction between AHM and PMHS with TEM. Furthermore, by adding TEOS into silica sources and adjusting TEOS/PMHS mass ratio, crystal phase of molybdenum carbides transferred from β-Mo2C to α-MoC1-x, and SiO2 structure changed from microporous to micro/mesoporous. Catalytic performances of samples were tested using CO hydrogenation as a probe reaction. The supported molybdenum carbides exhibited high selectivity for higher alcohol synthesis compared with bulk β-Mo2C and α-MoC1-x.

关键词： molybdenum carbides porous silica single-step carburization one-pot synthesis CO hydrogenation