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Development of tailored TiO_2 mesocrystals for solar driven photocatalysis 被引量:3
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作者 Peng Zhang Mamoru Fujitsuka Tetsuro Majima 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2016年第6期917-926,共10页
Ordered metal oxides superstructures have attracted much more attention in the fields of fuel generation and environmental purification owing to their unique physiochemical characteristics such as large surface area, ... Ordered metal oxides superstructures have attracted much more attention in the fields of fuel generation and environmental purification owing to their unique physiochemical characteristics such as large surface area, fine pore structure, efficient electronic mobility, and good stability. Very recently, TiOmesocrystals(TMCs) having superstructures self-assembled by TiOnanoparticle building blocks, are of considerable interest in current research and application ranging from UV to visible light attributed to their efficient charge separation and superior photocatalytic activity. In this review, we describe the common procedures to prepare unique TMCs and overview of recent developments of TMCs during last 3 years, especially the structure-related or electronic-effected mechanism in photocatalytic reaction. Further, we introduce the characterization and fundamental properties of modified TMCs by the means of single-particle fluorescence microscopy for unraveling the charge transport and photocatalytic properties of individual TMCs and time-resolved diffuse reflectance spectroscopy(TDR) for monitoring the charge transfer dynamics. Finally, various aspects on TMCs are discussed for the future developments of energy and environmental fields. 展开更多
关键词 TiO2 Mesocrystal PHOTOCATALYST topotactic transformation DOPING Charge separation CO-CATALYST Electron flow
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Topotactically constructed nickel-iron(oxy)hydroxide with abundant in-situ produced high-valent iron species for efficient water oxidation 被引量:5
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作者 Zhichong Kuang Song Liu +10 位作者 Xuning Li Meng Wang Xinyi Ren Jie Ding Rile Ge Wenhui Zhou Alexandre IRykov Moulay TSougrati Pierre-Emmanuel Lippens Yanqiang Huang Junhu Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第6期212-218,I0006,共8页
The low efficiency of oxygen evolution reaction(OER) is regarded as one of the major roadblocks for metal-air batteries and water electrolysis.Herein,a high-performance OER catalyst of NiFe_(0.2)(oxy)hydroxide(NiFe_(0... The low efficiency of oxygen evolution reaction(OER) is regarded as one of the major roadblocks for metal-air batteries and water electrolysis.Herein,a high-performance OER catalyst of NiFe_(0.2)(oxy)hydroxide(NiFe_(0.2)-O_(x)H_(y)) was developed through topotactic transformation of a Prussian blue analogue in an alkaline solution,which exhibits a low overpotential of only 263 mV to reach a current density of 10 mA cm^(-2) and a small Tafel slope of 35 mV dec-1.Ex-situ/operando Raman spectroscopy results indicated that the phase structure of NiFe_(0.2)-O_(x)H_(y) was irreversibly transformed from the type of α-Ni(OH)_(2) to γ-NiOOH with applying an anodic potential,while ex-situ/operando 57Fe Mossbauer spectroscopic studies evidenced the in-situ production of abundant high-valent iron species under OER conditions,which effectively promoted the OER catalysis.Our work elucidates that the amount of high-valent iron species in-situ produced in the NiFe(oxy)hydroxide has a positive correlation with its water oxidation reaction performance,which further deepens the understanding of the mechanism of NiFe-based electrocatalysts. 展开更多
关键词 Oxygen evolution reaction topotactic construction Structural transformation Operando Mssbauer spectroscopy High-valent iron ions
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Exchange-Biased NiFe_(2)O_(4)/NiO Nanocomposites Derived from NiFe-Layered Double Hydroxides as a Single Precursor 被引量:4
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作者 Xiaofei Zhao Sailong Xu +2 位作者 Lianying Wang Xue Duan Fazhi Zhang 《Nano Research》 SCIE EI CSCD 2010年第3期200-210,共11页
NiFe_(2)O_(4) nanoparticles(<10 nm)embedded in a NiO matrix have been fabricated by calcining the corresponding Ni^(Ⅱ)Fe^(Ⅲ)-layered double hydroxide(LDH)precursors at high temperature(500℃).Compared with the Ni... NiFe_(2)O_(4) nanoparticles(<10 nm)embedded in a NiO matrix have been fabricated by calcining the corresponding Ni^(Ⅱ)Fe^(Ⅲ)-layered double hydroxide(LDH)precursors at high temperature(500℃).Compared with the NiFe_(2)O_(4)/NiO nanocomposite obtained by calcination of a precursor prepared by a traditional chemical coprecipitation method,those derived from NiFe-LDH precursors show much higher blocking temperatures(TB)(~380 K).The enhanced magnetic stability can be ascribed to the much stronger interfacial interaction between NiFe_(2)O_(4) and NiO phases due to the topotactic nature of the transformation of the LDH precursor to the NiFe_(2)O_(4)/NiO composite material.Through tuning the Ni^(Ⅱ)/Fe^(Ⅲ) molar ratio of the NiFe-LDH precursor,the NiFe_(2)O_(4) concentration can be precisely controlled,and the TB value as well as the magnetic properties of the final material can also be regulated.This work represents a successful example of the fabrication of ferro(ferri)magnetic(FM)/antiferrimagnetic(AFM)systems with high magnetic stability from LDH precursors.This method is general and may be readily extended to other FM/AFM systems due to the wide range of available LDH precursors. 展开更多
关键词 Layered double hydroxide topotactic mechanism interfacial interaction exchange bias magnetic stability
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A multiphase nickel iron sulfide hybrid electrode for highly active oxygen evolution 被引量:4
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作者 Pengsong Li Xiuping Zhao +3 位作者 Xinxuan Duan Yaping Li Yun Kuang Xiaoming Sun 《Science China Materials》 SCIE EI CSCD 2020年第3期356-363,共8页
Development of highly active electrocatalysts for oxygen evolution reaction(OER)is one of the critical issues for water splitting,and most reported catalysts operate at overpotentials above 190 mV.Here we present a mu... Development of highly active electrocatalysts for oxygen evolution reaction(OER)is one of the critical issues for water splitting,and most reported catalysts operate at overpotentials above 190 mV.Here we present a multiphase nickel iron sulfide(MPS)hybrid electrode with a hierarchical structure of iron doped NiS and Ni3S2,possessing a benchmark OER activity in alkaline media with a potential as low as 1.33 V(vs.reversible hydrogen electrode)to drive an OER current density of 10 mA cm^-2.The Fe doped NiS,combined with highly conductive disulfide phase on porous Ni foam,is believed to be responsible for the ultrahigh activity.Furthermore,density functional theory simulation reveals that partially oxidized sulfur sites in Fe doped NiS could dramatically lower the energy barrier for the rate-determining elementary reaction,thus contributing to the active oxygen evolution. 展开更多
关键词 MULTIPHASE nickel iron sulfide topotactic conversion oxygen evolution reaction
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TiO_2 mesocrystals: Synthesis, formation mechanisms and applications 被引量:3
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作者 CAI JinGuang QI LiMin 《Science China Chemistry》 SCIE EI CAS 2012年第11期2318-2326,共9页
Mesocrystals, which are assemblies of crystallographically oriented nanocrystals, have received increasing attention due to their unique properties such as high crystallinity, high porosity, oriented subunit alignment... Mesocrystals, which are assemblies of crystallographically oriented nanocrystals, have received increasing attention due to their unique properties such as high crystallinity, high porosity, oriented subunit alignment, and similarity to highly sophisticated biominerals. However, the controlled synthesis of TiO 2 mesocrystals has not been realized until recently, probably because of the difficulty in accurately controlling the reaction processes that produce TiO 2 crystals. In this review, recent advances in the synthesis and applications of TiO 2 mesocrystals are summarized with particular attention paid to the mechanisms of their formation. Three typical pathways for the preparation of TiO 2 mesocrystals are discussed, namely topotactic transformation, direct synthesis in solution, and growth on supports. The potential applications of TiO 2 mesocrystals in lithium ion batteries, photocatalysis, enzyme immobilization, and antireflection materials are also described. 展开更多
关键词 MESOCRYSTALS TIO2 formation mechanisms topotactic transformation oriented attachment mesoscale assembly
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High current CO_(2)reduction realized by edge/defect-rich bismuth nanosheets 被引量:2
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作者 Jiaqi Xu Siheng Yang +8 位作者 Li Ji Jiawei Mao Wei Zhang Xueli Zheng Haiyan Fu Maolin Yuan Chengkai Yang Hua Chen Ruixiang Li 《Nano Research》 SCIE EI CSCD 2023年第1期53-61,共9页
CO_(2)electroreduction has been regarded as an appealing strategy for renewable energy storage.Recently,bismuth(Bi)electrocatalysts have attracted much attention due to their excellent formate selectivity.However,many... CO_(2)electroreduction has been regarded as an appealing strategy for renewable energy storage.Recently,bismuth(Bi)electrocatalysts have attracted much attention due to their excellent formate selectivity.However,many reported Bi electrocatalysts suffer from low current densities,which are insufficient for industrial applications.To reach the goal of high current CO_(2)reduction to formate,we fabricate Bi nanosheets(NS)with high activity through edge/terrace control and defect engineering strategy.Bi NS with preferential exposure sites are obtained by topotactic transformation,and the processes are clearly monitored by in-situ Raman and ex-situ X-ray diffraction(XRD).Bi NS-1 with a high fraction of edge sites and defect sites exhibits excellent performance,and the current density is up to ca.870 mA·cm^(−2)in the flow cell,far above the industrially applicable level(100 mA·cm^(−2)),with a formate Faradaic efficiency greater than 90%.In-situ Fourier transform infrared(FT-IR)spectra detect*OCHO,and theoretical calculations reveal that the formation energy of*OCHO on edges is lower than that on terraces,while the defects on edges further reduce the free energy changes(ΔG).The differential charge density spatial distributions reveal that the presence of defects on edges causes charge enrichment around the C–H bond,benefiting the stabilization of the*OCHO intermediate,thus remarkably lowering theΔG. 展开更多
关键词 CO_(2)electroreduction defect engineering bismuth nanosheet topotactic transformation
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Preparation of spatially uniform monolayer FeSexTe1−x(0
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作者 Zhongxu Wei Cui Ding +2 位作者 Yujie Sun Lili Wang Qi-Kun Xue 《Nano Research》 SCIE EI CSCD 2023年第1期1712-1716,共5页
Spatially uniform high-temperature superconducting films are highly desirable for exploring novel properties and popularizing applications.To improve the uniformity,we fabricate monolayer FeSexTe1−x(0<x≤1)films on... Spatially uniform high-temperature superconducting films are highly desirable for exploring novel properties and popularizing applications.To improve the uniformity,we fabricate monolayer FeSexTe1−x(0<x≤1)films on SrTiO3(001)by topotactic reaction of monolayer FeTe films with selenium.Using in situ low-temperature scanning tunneling microscopy/spectroscopy,we demonstrate atomic-level uniformity of element distribution and well-defined superconducting gaps of~15 meV in FeSexTe1−x films.In particular,the monolayer FeSe films exhibit fewer line defects and higher superfluid density as evidenced by sharper coherence peaks than those prepared by the co-evaporation method.Our results provide a promising way to optimize sample quality and lay a foundation for studying new physics and drawing reliable conclusions. 展开更多
关键词 monolayer FeSexTe1−x interface superconductivity topotactic reaction scanning tunneling microscopy
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Obtaining tetragonal FeAs layer and superconducting K_(x)Fe_(2)As_(2)by molecular beam epitaxy
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作者 Cui Ding Yuanzhao Li +3 位作者 Shuaihua Ji Ke He Lili Wang Qi-Kun Xue 《Nano Research》 SCIE EI CSCD 2023年第2期3040-3045,共6页
Atomic characterization on tetragonal FeAs layer and engineering FeAs superlattices is highly desirable to get deep insight into the multi-band superconductivity in iron-pnictides.We fabricate the tetragonal FeAs laye... Atomic characterization on tetragonal FeAs layer and engineering FeAs superlattices is highly desirable to get deep insight into the multi-band superconductivity in iron-pnictides.We fabricate the tetragonal FeAs layer by topotactic reaction of FeTe films with arsenic and then obtain KxFe_(2)As_(2)upon potassium intercalation using molecular beam epitaxy.The in-situ low-temperature√2×√2scanning tunneling microscopy/spectroscopy investigations demonstrate characteristic reconstruction of the FeAs layer and stripe pattern of KxFe_(2)As_(2),accompanied by the development of a superconducting-like gap.The ex-situ transport measurement with FeTe capping layers shows a superconducting transition with an onset temperature of 10 K.This work provides a promising way to characterize the FeAs layer directly and explore rich emergent physics with epitaxial superlattice design. 展开更多
关键词 tetragonal FeAs KxFe_(2)As_(2) interface enhanced superconductivity topotactic reaction molecular beam epitaxy
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Exploring the Spatial Control of Topotactic Phase Transitions Using Vertically Oriented Epitaxial Interfaces
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作者 Wenrui Zhang Jie Zhang +6 位作者 Shaobo Cheng Christopher M.Rouleau Kim Kisslinger Lihua Zhang Yimei Zhu Thomas Z.Ward Gyula Eres 《Nano-Micro Letters》 SCIE EI CAS CSCD 2022年第1期47-58,共12页
Engineering oxygen vacancy formation and distribution is a powerful route for controlling the oxygen sublattice evolution that affects diverse functional behavior.The controlling of the oxygen vacancy formation proces... Engineering oxygen vacancy formation and distribution is a powerful route for controlling the oxygen sublattice evolution that affects diverse functional behavior.The controlling of the oxygen vacancy formation process is particularly important for inducing topotactic phase transitions that occur by transformation of the oxygen sublattice.Here we demonstrate an epitaxial nanocomposite approach for exploring the spatial control of topotactic phase transition from a pristine perovskite phase to an oxygen vacancy-ordered brownmillerite(BM)phase in a model oxide La_(0.7)Sr_(0.3)MnO_(3)(LSMO).Incorporating a minority phase NiO in LSMO films creates ultrahigh density of vertically aligned epitaxial interfaces that strongly influence the oxygen vacancy formation and distribution in LSMO.Combined structural characterizations reveal strong interactions between NiO and LSMO across the epitaxial interfaces leading to a topotactic phase transition in LSMO accompanied by significant morphology evolution in NiO.Using the NiO nominal ratio as a single control parameter,we obtain intermediate topotactic nanostructures with distinct distribution of the transformed LSMO-BM phase,which enables systematic tuning of magnetic and electrical transport properties.The use of self-assembled heterostructure interfaces by the epitaxial nanocomposite platform enables more versatile design of topotactic phase structures and correlated functionalities that are sensitive to oxygen vacancies. 展开更多
关键词 Epitaxial interface NANOCOMPOSITE Functional oxides Oxygen vacancy topotactic phase transition
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A topotactic tailored synthesis of waxberry-like mixed-phase TiO_(2) hollow spheres for dye-sensitized solar cells
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作者 Yang-Hong Wu Kai-Yan Yuan +7 位作者 Yan-E He Heng Wu Li-Jiao Ma Gang Wang Xiao-Dong Qiao Bing-Xin Lei Zhen-Fan Sun Zhao-Qing Liu 《Chinese Chemical Letters》 SCIE CAS CSCD 2022年第2期963-967,共5页
The waxberry-like mixed-phase TiO_(2)hollow microstructures (WMTHMs) are controllably prepared via a topotactic synthetic method,involving the synthesis of monodispersed Ca TiO_(2)precursors by a solvothermal method a... The waxberry-like mixed-phase TiO_(2)hollow microstructures (WMTHMs) are controllably prepared via a topotactic synthetic method,involving the synthesis of monodispersed Ca TiO_(2)precursors by a solvothermal method and subsequently transforming them into TiO_(2)through a Na_(2)EDTA-assisted ion-exchange process.The ratio of anatase-rutile is adjustable,and the two phases are connected well with each other.WMTHMs are composed of radially aligned nanorods,speeding up the electron transport.The optimum WMTHMs sample shows a specific surface area of 68.05 m^(2)/g and exhibits an excellent light scattering capacity.The cell based on WMTHMs light scattering layer obtained an optimal efficiency of 9.12%.The improvement of cell efficiency is mainly attributed to the high specific surface area,the efficient light scattering,the appropriate ratio of anatase-rutile,the staggered bandgap structure,and the convenient one-dimensional electron transport channel. 展开更多
关键词 Titanium dioxide Phase composition topotactic methodology Hollow sphere Dye-sensitized solar cell
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过渡金属氮化物的制备及其在催化中的应用 被引量:3
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作者 沈强 卢春山 +2 位作者 马磊 姚红 李小年 《化工生产与技术》 CAS 2004年第1期33-36,共4页
过渡金属氮化物是一类金属间充型化合物,兼具有共价化合物、离子晶体和过渡金属的性质。在基本不破坏氧化物前驱体晶体结构和严格的氮化条件下,氧化物前驱体通过程序升温氮化经由“局部规整反应”可以制备出高表面积的过渡金属氮化物。... 过渡金属氮化物是一类金属间充型化合物,兼具有共价化合物、离子晶体和过渡金属的性质。在基本不破坏氧化物前驱体晶体结构和严格的氮化条件下,氧化物前驱体通过程序升温氮化经由“局部规整反应”可以制备出高表面积的过渡金属氮化物。它的表面性质和催化性能类似于Pt和Rh等贵金属元素,在氨合成、氨分解、加氢脱硫(HDS)、加氢脱氮(HDN)、F-T合成、NO还原等许多涉氢反应中都表现了良好的催化性能,被誉为“准铂催化剂”,并已经展示了重要的理论研究意义和潜在的应用前景。 展开更多
关键词 过渡金属氮化物 催化 局部规整反应 表面性质
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超大孔分子筛,十年再回顾 被引量:5
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作者 闻嘉丽 张钧豪 姜久兴 《高等学校化学学报》 SCIE EI CAS CSCD 北大核心 2021年第1期101-116,共16页
沸石分子筛是一类重要的具有明确孔道结构以及催化位点的结晶孔材料.但是由于其微孔开口的本质限制了其在大分子吸附与转化方面的应用.10年前,西班牙ITQ研究所的Corma教授、吉林大学于吉红教授以及本文通讯作者发表了一篇关于超大孔分... 沸石分子筛是一类重要的具有明确孔道结构以及催化位点的结晶孔材料.但是由于其微孔开口的本质限制了其在大分子吸附与转化方面的应用.10年前,西班牙ITQ研究所的Corma教授、吉林大学于吉红教授以及本文通讯作者发表了一篇关于超大孔分子筛的历史回顾文章.该文从超大孔分子筛的合成、结构、假想结构以及催化性能等方面进行了综述.这一类材料填补了传统沸石分子筛和有序介孔材料之间的孔径缺口.在最近10年中,多种新型超大孔分子筛以及新颖的合成方法陆续被报道.本文对该方向近10年中的研究进行了综合评述. 展开更多
关键词 超大孔 沸石分子筛 有机机构导向剂 拓扑转 Assembly-disassembly-organization-reassembly(ADOR)
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介观TiO_(2)晶体材料的拓扑转变合成及其性能 被引量:2
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作者 常帅康 刘闯 +4 位作者 李坤宸 李波 王芳芳 陆彩云 陈常东 《辽宁石油化工大学学报》 CAS 2023年第1期27-31,共5页
以层状结构的钛酸盐HTO(H_(4x/3)Ti_(2-x/3)□_(x/3)O_(4)•nH_(2)O)为原料,采用水热的方法合成了金红石型介观TiO2晶体。通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)等测试手段,研究了反应温度对利用拓扑结构转变方式合成的金红... 以层状结构的钛酸盐HTO(H_(4x/3)Ti_(2-x/3)□_(x/3)O_(4)•nH_(2)O)为原料,采用水热的方法合成了金红石型介观TiO2晶体。通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)等测试手段,研究了反应温度对利用拓扑结构转变方式合成的金红石型介观TiO_(2)晶体材料的影响。结果表明,金红石型TiO_(2)晶体材料可以在反应体系pH为0.5的条件下得到,当反应温度升高到120℃时,形成了金红石型介观TiO_(2)晶体材料。以罗丹明B(RhB)为污染物模型进行了降解实验。结果表明,120℃时金红石型介观TiO_(2)晶体材料的光催化活性明显高于其他样品,主要是由于介观晶体具有较为特殊的电子传导特性,有助于电子与空穴的分离。染料敏化太阳能电池(DSSCs)实验结果表明,120℃时所形成的介观晶体结构有助于光生载流子的快速迁移,从而获得较高的电池特性。 展开更多
关键词 介观晶体 水热 拓扑相变 光(电)催化
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二维层状分子筛前驱体的合成、改性及催化应用 被引量:2
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作者 赵侦超 张维萍 《物理化学学报》 SCIE CAS CSCD 北大核心 2016年第10期2475-2487,共13页
二维层状分子筛前驱体具有三维分子筛的层结构单元,具备母体分子筛的特性,其开放二维片层骨架结构给合成新分子筛以及基于其改性得到新衍生结构分子筛提供新机遇,是近年来分子筛研究领域一个新热点。大量二维片层前驱体可直接合成或通... 二维层状分子筛前驱体具有三维分子筛的层结构单元,具备母体分子筛的特性,其开放二维片层骨架结构给合成新分子筛以及基于其改性得到新衍生结构分子筛提供新机遇,是近年来分子筛研究领域一个新热点。大量二维片层前驱体可直接合成或通过三维分子筛后处理获得,基于二维片层前驱体人们发展了溶胀、剥层、柱撑、原子扩孔、层重组等层操纵的策略,通过这些策略一些常规方法难以合成或不符合理论规则的分子筛被合成出来,这极大地丰富了二维层状分子筛前驱体的研究领域,扩展了其应用范围。本文概述了二维层状分子筛前驱体的结构特点,系统总结了近年来二维层状分子筛前驱体的合成方法,在此基础上着重阐述了其改性获得新结构分子筛的新策略,并介绍了在多相催化反应中的应用。 展开更多
关键词 二维片层 层状分子筛 拓扑转变 结构改性 催化应用
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ZnAl-LDHs热致拓扑转变的理论及实验研究 被引量:1
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作者 孟庆婷 鄢红 《中国科学:化学》 CAS CSCD 北大核心 2017年第4期493-502,共10页
层状复合金属氢氧化物(LDHs)材料具有纳米尺度的二维层状结构.其晶体结构在煅烧的条件下可发生热致拓扑转变,利用此性质可以LDHs为前驱体制备高分散催化剂.本文采用基于密度泛函的第一性原理分子动力学模拟方法并结合热重分析(TG-DTA)... 层状复合金属氢氧化物(LDHs)材料具有纳米尺度的二维层状结构.其晶体结构在煅烧的条件下可发生热致拓扑转变,利用此性质可以LDHs为前驱体制备高分散催化剂.本文采用基于密度泛函的第一性原理分子动力学模拟方法并结合热重分析(TG-DTA)研究了ZnAl-LDHs在升温过程的拓扑转变机理.通过TG-DTA数据明确了发生分解反应的两个关键性温度273和800℃,并在这两个温度进行模拟.在273℃,模拟了LDHs层间阴离子分解及层板脱羟基过程中金属离子的迁移机理,结果表明,层间阴离子CO_3^(2-)通过与主体层板作用形成单齿配体进行分解,产物水分子先于CO_2释放到层间区域内.此时LDHs层板结构已经坍塌,金属离子在层板方向及垂直层板方向都发生了显著的迁移,拓扑不变量(层板方向迁移度)变化明显.因此,ZnAl-LDHs不存在记忆效应.在800℃,模拟发现LDHs结构已经完全坍塌,生成了多孔性的混合金属氧化物,与文献实验结果相符合.本文从原子水平上理解了LDHs整个结构从分解的起始阶段到完全脱水的演变过程,并解释了ZnAl-LDHs没有记忆效应的原因,为认识LDHs热致拓扑转变机理,设计高分散催化剂提供了有益的理论信息和指导. 展开更多
关键词 ZnAl-LDHs 热分解 拓扑转变 分子动力学模拟 密度泛函理论
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TOPOTACTIC INTERGROWTH OF LONGQUAN MAGNESIOAMPHIBOLE
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作者 薛纪越 马军 张富生 《Chinese Science Bulletin》 SCIE EI CAS 1991年第18期1553-1556,共4页
Ⅰ. OCCURRENCE AND GENERAL FEATURES OF LONGQUAN MAGNESIOAMPHIBOLEThe magnesioamphibole studied in this note was sampled from peridotite block in Longquan tectonic melange zone of Zhejiang Province, China. It appears i... Ⅰ. OCCURRENCE AND GENERAL FEATURES OF LONGQUAN MAGNESIOAMPHIBOLEThe magnesioamphibole studied in this note was sampled from peridotite block in Longquan tectonic melange zone of Zhejiang Province, China. It appears in bunchy or fibrous aggregates around the block. The length of the crystal ranges from several mm to about 1 cm. It presents inchned extinction with cANg= 10°—13°under crossed polars. According to the observation of thin sections, it is known that olivine, tale and serpentine 展开更多
关键词 topotnctic INTERGROWTH magnesiocummingtonite anthophyllite.
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低温合成超导体Ba_(1-x)K_xBiO_3(英文)
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作者 刘孟 李国宝 +2 位作者 王稼国 廖复辉 林建华 《物理化学学报》 SCIE CAS CSCD 北大核心 2014年第9期1611-1615,共5页
先以BaCO3和Bi2O3为原料由传统的固相反应制备纯BaBiO3,然后在低温下将用KOH-KF熔盐处理这样的拓扑反应合成了Ba1-xKxBiO3超导体.所有样品均进行了粉末X射线衍射(XRD)和磁性表征.XRD结果表明,所得Ba1-xKxBiO3样品均为纯相,且均可用赝立... 先以BaCO3和Bi2O3为原料由传统的固相反应制备纯BaBiO3,然后在低温下将用KOH-KF熔盐处理这样的拓扑反应合成了Ba1-xKxBiO3超导体.所有样品均进行了粉末X射线衍射(XRD)和磁性表征.XRD结果表明,所得Ba1-xKxBiO3样品均为纯相,且均可用赝立方晶胞指标化.磁性测量表明所有样品具有超导电性,最高超导转变温度(Tc)为30.6 K.讨论了反应时间、前驱体与熔盐质量比对超导转变温度的影响.最佳的反应条件为:反应温度450°C,反应时间4 h,BaBiO3:KOH:KF质量比1:5:2.5. 展开更多
关键词 Ba1-xKxBiO3 X射线衍射 铋酸盐超导体 拓扑反应
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类水滑石拓扑转变材料在光、电能源催化中的应用
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作者 段驰 李振华 +1 位作者 施润 张铁锐 《硅酸盐学报》 EI CAS CSCD 北大核心 2022年第5期1410-1421,共12页
近年来,有关类水滑石拓扑转变材料在光、电催化领域如产氢、C1化学转化等方面的研究被广泛报道。研究表明,在不同的煅烧温度、气氛等拓扑转变条件下处理类水滑石,不仅可以提高活性位的分散程度,而且可以实现催化剂物相组成、特定晶面和... 近年来,有关类水滑石拓扑转变材料在光、电催化领域如产氢、C1化学转化等方面的研究被广泛报道。研究表明,在不同的煅烧温度、气氛等拓扑转变条件下处理类水滑石,不仅可以提高活性位的分散程度,而且可以实现催化剂物相组成、特定晶面和界面结构的调控。该材料在多种能源催化转化利用中呈现出优越的性能。本文介绍了类水滑石拓扑转变的过程及机制,并分别从光催化、电催化2个方面综述类水滑石拓扑转变材料在能源催化领域的研究进展。 展开更多
关键词 类水滑石 拓扑转变 光催化 电催化
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TiO_(2)同质体材料的拓扑转变合成及其性能的研究
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作者 陈常东 李哲 +3 位作者 李珂 丛金莹 杨宇航 王芳芳 《辽宁石油化工大学学报》 CAS 2022年第3期37-41,共5页
采用H_(4x/3)Ti_(2-x/3)□_(x/3)O_(4)·nH_(2)O(HTO)为前驱体原料,通过水浴浸渍的方式在HTO的表面负载纳米级氧化钛颗粒(ST01),采用焙烧的方法拓扑合成TiO_(2)同质结构复合材料。利用X射线衍射(XRD)、拉曼光谱(Raman)等测试手段,... 采用H_(4x/3)Ti_(2-x/3)□_(x/3)O_(4)·nH_(2)O(HTO)为前驱体原料,通过水浴浸渍的方式在HTO的表面负载纳米级氧化钛颗粒(ST01),采用焙烧的方法拓扑合成TiO_(2)同质结构复合材料。利用X射线衍射(XRD)、拉曼光谱(Raman)等测试手段,详细研究了焙烧温度对TiO_(2)相变过程的影响。结果表明,HTO随着温度的升高逐渐由单斜结构的TiO_(2)(B)转变成锐钛矿结构,再转变至金红石结构,且形成多种不同结构、组成的TiO_(2)同质复合体材料。以罗丹明B(RhB)为污染物模型进行降解实验,600℃时样品的光催化活性明显高于其他样品,主要是由于此时样品的电子与空穴分离效率较高,说明同质复合体TiO_(2)结构和组成影响了其光催化活性。此外,染料敏化太阳能电池(DSSCs)实验表明,600℃时样品的光电性能较高,其原因是二维片状形貌有助于光生载流子的快速迁移。 展开更多
关键词 TiO_(2) 同质结构 拓扑相变 光(电)催化
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水热法制备介孔氧化铝的形貌演化研究(英文) 被引量:2
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作者 李艳辉 彭诚 +2 位作者 赵威 白明敏 饶平根 《无机材料学报》 SCIE EI CAS CSCD 北大核心 2014年第10期1115-1120,共6页
以硫酸铝铵、尿素为原料,PEG2000作为分散剂,通过水热法合成了三种形貌的勃姆石(AlOOH)。实验结果显示,调节水热温度可以制备出AlOOH微球、微纤维和3D分级结构的AlOOH。经SEM分析可知,在煅烧过程中,AlOOH分解转化为γ-Al2O3,该过程为... 以硫酸铝铵、尿素为原料,PEG2000作为分散剂,通过水热法合成了三种形貌的勃姆石(AlOOH)。实验结果显示,调节水热温度可以制备出AlOOH微球、微纤维和3D分级结构的AlOOH。经SEM分析可知,在煅烧过程中,AlOOH分解转化为γ-Al2O3,该过程为拓扑过程,即形貌未发生变化。TEM结果显示,介孔均匀地分布在AlOOH内。基于此,我们提出了温度-形貌生长机制。此外,还研究了γ-Al2O3的光致发光性能,以325 nm为激发光谱时,其发生光谱的波长在380~500 nm,光谱中心在409和467 nm处。 展开更多
关键词 勃姆石 Γ-AL2O3 拓扑 介孔 光致发光
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