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Chinese Science Bulletin 2005年第22期50卷 2575-2581页

作者： david g. evans Ministry of Education Key Laboratory of Science and Technology of Controllable Chemical Reactions Beijing University of Chemical Tech- nology Beijing 100029 China

A novel organic-inorganic composite, sorbic acid intercalated zinc aluminum layered double hydroxides (SA-ZnAl-LDHs) has been successfully assembled by a sim- ple direct coprecipitation method. A holistic approach in- cluding normal XRD, FT-IR, and UV-Vis measurements and simultaneous Tg/DTA/MS and in situ HT-XRD techniques was employed to explore the supramolecular intercalation structure and the thermal decomposition properties of as-synthesized SA-ZnAl-LDHs material.

关键词：氢氧化铝超分子结构热量分解插入结构 HT-XRD 有机化合物

Preparation and photochromic properties of NiAl-NO_3-LDHs/LDPE composite

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Chinese Science Bulletin 2007年第7期52卷 877-882页

作者： CHO Kyuhaeng david g.evans State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology

Nanoscale NiAl-NO3-LDHs with good crystallinity have been synthesized by a method, Separate Nucleation and Aging Steps (SNAS). An NiAl-NO3-LDHs/LDPE composite was prepared by blending NiAl-NO3-LDHs and LDPE in a heated double-roller mixer. The color of this composite changed from olive green to steel gray under UV irradiation. After heating at 80oC for 2 h, the color returned to olive green. The effect of varying the amount of added NiAl-NO3-LDHs and UV exposure time on the photochromic properties of the composite has been investigated. The results showed that the photochromic phenomenon becomes more apparent with increasing amount of NiAl-NO3-LDHs. When the amount reaches 5%, the composite exhibits good photochromic properties and reproducibility. The color change rate of the composite reaches a maximum when the irradiation time exceeds 20 min. The addition of LDPE improves the photochromic cyclability of NiAl-NO3-LDHs significantly. The addition of nanoscale NiAl-NO3-LDHs also improves the mechanical properties of LDPE to some extent.

关键词： NiAl-NO3-LDHs 低密度聚乙烯纳米级复合物合成对光反应变色结晶度

Layer-by-layer assembly of long-afterglow self-supporting thin films with dual-stimuli-responsive phosphorescence and antiforgery applications

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Nano Research 2017年第10期10卷 3606-3617页

作者： Rui gao Dongpeng Yan david g. evans Xue Duan State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China Beijing Key Laboratory of Energy Conversion and Storage Materials College of Chemistry Beijing Normal University Beijing 100875 China

The assembly of thin films （TFs） having long-lasting luminescence can be expected to play an important role in the development of new-generation smart sensors, anti-counterfeiting materials, and information-encryption systems. However, such films are limited compared with their powder and solution counterparts. In this study, by exploiting the self-organization of phosphors in the two-dimensional （2D） galleries between clay nanosheets, we developed a method for the ordered assembly of long-afterglow TFs by utilizing a hydrogen-bonding layer-by-layer （LBL） process. Compared with the pristine powder, the TFs exhibit high polarization and up-conversion room-temperature phosphorescence （RTP）, as well as enhanced quantum yields and luminescence lifetimes, allowing them to be used as room-temperature phosphorescent sensors for humidity and oxygen. Moreover, modified clay-based hybrids with multicolor RTP can serve as anti-counterfeiting marks and triple-mode 2D barcode displays. We anticipate that the LBL assembly process can be extended to the fabrication of other inorganic--organic room-temperature phosphorescent hybrids with smart luminescent sensor and antiforgery applications.

关键词： layer-by-layer self-supporting thin film two-dimensional (2D) ultrathin nanosheets sensor phosphorescence

Multi-dimensional, light-controlled switch of fluorescence resonance energy transfer based on orderly assembly of 0D dye@micro-micelles and 2D ultrathin-layered nanosheets

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Nano Research 2016年第12期9卷 3828-3838页

作者： Zhixiong Li Ruizheng Liang Simin Xu Wendi Liu Dongpeng Yan Min Wei david g. evans Xue Duan State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China

Fluorescence resonance energy transfer （FRET） systems have broad applications in visual detection, intelligent materials, and biological imaging, all of which favor the transmission of light through multiple dimensions and in diverse directions. Herein, we have demonstrated multi-dimensional （0D and 2D） FRET within a multi-layer ultrathin film （UTF） by employing a layer-by-layer （LBL） assembly technique. The anionic block copolymer micelle poly（tert-butyl acrylate- co-ethyl acrylate-co-methacrylic acid）（PTBEM） is chosen as a molecular carrier for the incorporation of bis（8-hydroxyquinolate） zinc （Znq2） and open-ring merocyanine （MC）（denoted as （Znq2/MC）@PTBEM）. Alternatively, electrostatic assembly is performed with cationic layered double hydroxide （LDH） nanosheets （denoted as [（Znq2/MC）@PTBEM/LDH]n）. This [（Znq2/MC）@PTBEM/ LDH]n system offers a multi-dimensional propagation medium and ensures that the FRET donor and acceptor are located within their F6rster radii in each direction. The system demonstrates a FRET process that can be switched via alternating ultraviolet/visible （UV/vis） irradiation, with tunable blue-green/red fluorescence, resulting in a FRET efficiency as high as 81.7%. It is expected that this assembly method, which uses 0D micelles on a 2D layered material, can be extended to other systems for further development of multi-dimensional FRET.

关键词： bis(8-hydroxyquinolate)zinc (Znq2) open-ring merocyanine layered double hydroxide layer-by-layerself-assembly multi-dimensionalfluorescence resonanceenergy transfer

Ti-MCM-41催化剂的表面性质及介质极性对苯羟化反应化学选择性的影响

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催化学报 2001年第5期22卷 475-478页

作者：马辉何静 david g evans 段雪北京化工大学可控化学反应教育部重点实验室北京100029

用不同的铝源改性Ti MCM 41催化剂 ,得到了具有长程有序结构、n(Si) /n(Ti) =2 5的不同Si/Al比的改性Ti MCM 41.通过研究芳烃羟化反应随催化剂表面性质的变化规律发现 ,调变催化剂的表面性质 ,可控制反应物苯及目的产物苯酚与Al Ti MCM... 详细信息

用不同的铝源改性Ti MCM 41催化剂 ,得到了具有长程有序结构、n(Si) /n(Ti) =2 5的不同Si/Al比的改性Ti MCM 41.通过研究芳烃羟化反应随催化剂表面性质的变化规律发现 ,调变催化剂的表面性质 ,可控制反应物苯及目的产物苯酚与Al Ti MCM 41催化活性中心接近的程度 ,从而可实现对芳烃羟化反应化学选择性的控制 .介质极性对芳烃的化学亲和选择性也有影响。

关键词： MCM-41沸石表面性质介质极性苯羟化反应催化剂催化性能化学选择性

Layered double hydroxide monolayers for controlled loading and targeted delivery of anticancer drugs

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Nano Research 2018年第1期11卷 195-205页

作者： Xuan Mei Simin Xu Tongyang Hu Liuqi Peng Rui gao Ruizheng Liang Min Wei david g. evans Xue Duan State Key Laboratory of Chemical Resource Engineering Beiing Advanced Innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical Technology Beijing 100029 China

Two-dimensional （2D） nanomaterials have gained tremendous attention in the field of biomedicine because of their high specific surface areas and fascinating physicochemical properties. Herein, 2D monolayered double hydroxide （MLDH） nanosheets were employed to localize doxorubicin （DOX）, an anticancer drug, with a loading capacity of as high as 3.6 ***-1 （w/w）. Structural characterizations and theoretical calculations indicate that the DOX molecule is uniformly arranged and oriented at the surface of the MLDHs with a binding energy of 15.90 eV, showing significant electrostatic interaction. With the assistance of the targeting agent folic acid （FA）, DOX-FA/MLDHs demonstrate targeted cellular uptake and superior anticancer behavior based on in vitro tests performed with cancer cells. In addition, this composite material exhibits a selective release toward cancer cells and good biocompatibility with normal cells, which would guarantee its practical applications in cancer therapy.

关键词： two-dimensional nanomaterials monolayer layered double hydroxide(LDH) drug loading controllable release

Nanoseparation-lnspired Manipulation of the Synthesis of CdS Nanorods

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Nano Research 2011年第2期4卷 226-232页

作者： Xiaoming Sun Xiuju Ma Lu Bai Junfeng Liu Zheng Chang david g. evans Xue Duan Jiaou Wang Joseph F. Chiang State Key Laboratory of Chemical Resource Engineering RO. Box 98 Beijing University of Chemical Technology Beijing 100029 China Institute of High Energy Physics Beijing 100039 China Department of Chemistry and Biochemistry SUNY-Oneonta Oneonta NY 13820 USA

CdS nanorods have been sorted by length using a density gradient ultracentrifuge rate separation method. The fractions containing longer rods showed relatively stronger oxygen-related surface trap emission, while the shorter ones had dominant band-edge emission. These results suggest that the final length distribution of CdS nanorods is not a result of random nucleation and growth, but is related to the local synthesis conditions. Inspired by these findings, different synthesis environments （N2, air, and 02） have been employed in order to tailor the length distribution. In addition to the rod length, the photoluminescence properties of CdS nanorods can also be manipulated. Increasing the oxygen partial pressure significantly changed the growth behavior of CdS nanorods by improving the anisotropic growth.

关键词： Nanoseparation quantum rods CdS photoluminescence controlled synthesis

Co^2＋含量对CoAl-LDHs焙烧产物结构、组成及其生长碳纳米管的影响

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无机化学学报 2008年第6期24卷 886-891页

作者： Halidou I.Hima 项顼张璐李峰 david g.evans 北京化工大学化工资源有效利用国家重点实验室北京100029

采用成核晶化隔离法将Co2+引入层状双金属氢氧化物(LDHs),得到了含不同Co2+/Al3+物质的量的比为1∶1,2∶1,3∶1的二元钴铝碳酸根型LDHs(CoAl-LDHs)。通过X射线衍射(XRD)、透射电镜(TEM)、扫描电镜-能量散射谱(SEM-EDS)、拉曼光谱(Raman... 详细信息

采用成核晶化隔离法将Co2+引入层状双金属氢氧化物(LDHs),得到了含不同Co2+/Al3+物质的量的比为1∶1,2∶1,3∶1的二元钴铝碳酸根型LDHs(CoAl-LDHs)。通过X射线衍射(XRD)、透射电镜(TEM)、扫描电镜-能量散射谱(SEM-EDS)、拉曼光谱(Raman)、程序升温还原(TPR)及X射线光电子能谱(XPS)等方法对CoAl-LDHs焙烧产物的结构、组成及其化学气相沉积(CCVD)催化生长多壁碳纳米管(CNTs)进行了研究。结果表明:CoAl-LDHs前体中钴的含量可以明显改变焙烧产物的组成分布和还原性能,并最终影响CNTs的生长,其中以nCo2+/nAl3+比为2/1的LDHs作为催化剂前体可以得到管径均匀和石墨化程度高的CNTs,这与还原得到的纳米活性Co颗粒均匀分散有关。

关键词：层状双金属氢氧化物碳纳米管催化钴

柠檬酸溶胶凝胶法制备LiCoO_2电极材料及其表征

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无机化学学报 2003年第6期19卷 603-608页

作者：王兴杰杨文胜卫敏 david g.evans 段雪北京化工大学可控化学反应科学与技术基础教育部重点实验室北京100029

LiCoO2 precursors of the cathode material for lithium ion batteries were prepared from lithium hydroxide, basic cobalt carbonate and citric acid by a sol gel method. The LiCoO2 samples were obtained by sintering the gel precursors at different temperatures and for different times. The thermal decomposition behavior of the gel precursors was examined by means of thermo gravimetric analysis and differential thermal analysis using a PCT IA thermal analyzer system. Their structures and morphologies were characterized by powder XRD and SEM techniques. It was found that using citric acid realized that the formation of LiCoO2 crystal can be clearly differentiated to the nucleation and growth processes of the crystals; furthermore, the crystal size can be controlled. Electrochemical tests using the LAND BT1 10 test system showed the electrochemical performance of the material is affected by its integrity and stability.

关键词：锂离子电池正极材料柠檬酸溶胶凝胶法合成结构表征电化学性能制备

γ-Al_2O_3表面原位合成Ni-Al-CO_3 LDHs研究

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无机化学学报 2004年第5期20卷 596-602页

作者：毛纾冰李殿卿张法智 david g.evans 段雪北京化工大学可控化学反应科学与技术基础教育部重点实验室北京100029

Ni-Al-CO3 LDHs/γ-Al2O3 have been prepared using an in-situ synthesis technique. NH3·H2O was chosen as activation agent of Al on the γ-Al2O3 surface as well as precipitant. Ni-Al-CO3 LDHs/γ-Al2O3 was synthesized by controlling the reaction conditions such as temperature, concentration of Ni2+ and initial pH. The crystalline structure, chemical composition and porous structure were characterized by means of XRD, FT-IR, Tg-DTA, 27Al MAS-NMR and N2 adsorption-desorption. The resulting sample of Ni-Al-CO3 LDHs/γ-Al2O3 possesses higher specific area and narrower pore distribution, in which Ni-Al-CO3 LDHs are located on the surface of γ-Al2O3 and share the same Al-O bonds with the γ-Al2O3 lattice. Finally a possible structural model was proposed to account for the porous characters of Ni-Al-CO3 LDHs/γ-Al2O3.

关键词： γ-氧化铝表面原位合成水滑石催化剂 LDHs 孔结构比表面积含镍LDHs