scholarly journals Diffusion Of Indigo Molecules Inside The Palygorskite Clay Channels

2011 ◽  
Vol 1319 ◽  
Author(s):  
Catherine Dejoie ◽  
Pauline Martinetto ◽  
Eric Dooryhée ◽  
Ross Brown ◽  
Sylvie Blanc ◽  
...  

ABSTRACTThe search for durable dyes led several past civilizations to develop artificial pigments. Maya Blue (MB), manufactured in pre-Columbian Mesoamerica, is one of the best known examples of an organic-inorganic hybrid material. Its durability is due to the unique association of indigo molecule and palygorskite, a particular fibrous clay occurring in Yucatan. Despite 50 years of sustained interest, the microscopic structure of MB and its relation to the durability remain open questions. Combining new thermogravimetric and synchrotron X-ray diffraction analyses, we show that indigo molecules can diffuse into the channel of the palygorskite during the heating process, replacing zeolitic water and stabilizing the room temperature phases of the clay.

2016 ◽  
Vol 850 ◽  
pp. 191-196 ◽  
Author(s):  
Wei Wang ◽  
Cun Lei Zou ◽  
Ren Geng Li ◽  
Wen Wen ◽  
Hui Jun Kang ◽  
...  

In situ synchrotron X-ray diffraction was used to study a deformed Cu-0.88 Fe-0.24 P alloy during heating process. The measurements were performed at room temperature and also at high temperatures up to 893 K in order to determine the recovery, ageing and recrystallization process. With the increase of temperature, the angles of copper matrix peaks moved left and the FWHM (full width at half maximum) decreased slightly. Fe3P precipitates were first detected at 533 K, reached the maximum at 673 K, and re-dissolved into matrix at 853 K. A dramatic decrease in FWHM was observed accompanied by the precipitation of Fe3P phases, indicating the reduction of lattice distortion of copper matrix.


NANO ◽  
2016 ◽  
Vol 11 (07) ◽  
pp. 1650079 ◽  
Author(s):  
Wenjun Yan ◽  
Ming Hu ◽  
Jiran Liang ◽  
Dengfeng Wang ◽  
Yulong Wei ◽  
...  

A novel composite of Au-functionalized porous silicon (PS)/V2O5 nanorods (PS/V2O5:Au) was prepared to detect NO2 gas. PS/V2O5 nanorods were synthesized by a heating process of pure vanadium film on PS, and then the obtained PS/V2O5 nanorods were functionalized with dispersed Au nanoparticles. Various analytical techniques, such as field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), have been employed to investigate the properties of PS/V2O5:Au. Herein, the PS/V2O5:Au sample exhibited improved NO2-sensing performances in response, stability and selectivity at room temperature (25[Formula: see text]C), compared with the pure PS/V2O5 nanorods. These phenomena were closely related to not only the dispersed Au nanoparticles acting as a catalyst but also the p-n heterojunctions between PS and V2O5 nanorods. Whereas, more Au nanoparticles suppressed the improvement of response to NO2 gas.


2015 ◽  
Vol 70 (5) ◽  
pp. 311-316
Author(s):  
Yue Cao ◽  
Kai Yu ◽  
Chun-mei Wang ◽  
Chun-xiao Wang ◽  
Zhan-hua Su ◽  
...  

AbstractAn organic-inorganic hybrid compound based on {PMo12} layers, [Ag(pz)2]6[PMo12O40]2·3H2O 1 (pz = pyrazole), has been hydrothermally synthesized and characterized by elemental analysis, TG, IR spectroscopy, and single-crystal X-ray diffraction. Two crystallographically independent [PMo12O40]3– clusters are arranged in an AB–AB mode to give two kinds of supramolecular layers. The layers are further connected in a special alternating mode by [Ag(pz)2]+ linkers to form complex 3-D supramolecular network. Compound 1 exhibits good electrocatalytic activity in the reduction of hydrogen peroxide and shows fluorescence in the solid state at room temperature.


Author(s):  
C. Wolpers ◽  
R. Blaschke

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.


Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.


2020 ◽  
Author(s):  
Pia Vervoorts ◽  
Stefan Burger ◽  
Karina Hemmer ◽  
Gregor Kieslich

The zeolitic imidazolate frameworks ZIF-8 and ZIF-67 harbour a series of fascinating stimuli responsive properties. Looking at their responsitivity to hydrostatic pressure as stimulus, open questions exist regarding the isotropic compression with non-penetrating pressure transmitting media. By applying a state-of-the-art high-pressure powder X-ray diffraction setup, we revisit the high-pressure behaviour of ZIF-8 and ZIF-67 up to <i>p</i> = 0.4 GPa in small pressure increments. We observe a drastic, reversible change of high-pressure powder X-ray diffraction data at <i>p</i> = 0.3 GPa, discovering large volume structural flexibility in ZIF-8 and ZIF-67. Our results imply a shallow underlying energy landscape in ZIF-8 and ZIF-67, an observation that might point at rich polymorphism of ZIF-8 and ZIF-67, similar to ZIF-4(Zn).<br>


2020 ◽  
Author(s):  
Pia Vervoorts ◽  
Stefan Burger ◽  
Karina Hemmer ◽  
Gregor Kieslich

The zeolitic imidazolate frameworks ZIF-8 and ZIF-67 harbour a series of fascinating stimuli responsive properties. Looking at their responsitivity to hydrostatic pressure as stimulus, open questions exist regarding the isotropic compression with non-penetrating pressure transmitting media. By applying a state-of-the-art high-pressure powder X-ray diffraction setup, we revisit the high-pressure behaviour of ZIF-8 and ZIF-67 up to <i>p</i> = 0.4 GPa in small pressure increments. We observe a drastic, reversible change of high-pressure powder X-ray diffraction data at <i>p</i> = 0.3 GPa, discovering large volume structural flexibility in ZIF-8 and ZIF-67. Our results imply a shallow underlying energy landscape in ZIF-8 and ZIF-67, an observation that might point at rich polymorphism of ZIF-8 and ZIF-67, similar to ZIF-4(Zn).<br>


2018 ◽  
Author(s):  
Katherine Marczenko ◽  
James Goettel ◽  
Gary Schrobilgen

Oxygen coordination to the Xe(VI) atom of XeO<sub>3</sub> was observed in its adducts with triphenylphosphine oxide, dimethylsulfoxide, pyridine-N-oxide, and acetone. The crystalline adducts were characterized by low-temperature, single-crystal X-ray diffraction and Raman spectroscopy. Unlike solid XeO<sub>3</sub>, which detonates when mechanically or thermally shocked, the solid [(C<sub>6</sub>H<sub>5</sub>)<sub>3</sub>PO]<sub>2</sub>XeO<sub>3</sub>, [(CH<sub>3</sub>)<sub>2</sub>SO]<sub>3</sub>(XeO<sub>3</sub>)<sub>2</sub>,<sub> </sub>and (C<sub>5</sub>H<sub>5</sub>NO)<sub>3</sub>(XeO<sub>3</sub>)<sub>2</sub> adducts are insensitive to mechanical shock, but undergo rapid deflagration when ignited by a flame. Both [(C<sub>6</sub>H<sub>5</sub>)<sub>3</sub>PO]<sub>2</sub>XeO<sub>3 </sub>and (C<sub>5</sub>H<sub>5</sub>NO)<sub>3</sub>(XeO<sub>3</sub>)<sub>2</sub> are air-stable whereas [(CH<sub>3</sub>)<sub>2</sub>SO]<sub>3</sub>(XeO<sub>3</sub>)<sub>2</sub> slowly decomposes over several days and [(CH<sub>3</sub>)<sub>2</sub>CO]<sub>3</sub>XeO<sub>3</sub> undergoes adduct dissociation at room temperature. The xenon coordination sphere of [(C<sub>6</sub>H<sub>5</sub>)<sub>3</sub>PO]<sub>2</sub>XeO<sub>3</sub> is a distorted square pyramid which provides the first example of a five-coordinate XeO<sub>3</sub> adduct. The xenon coordination spheres of the remaining adducts are distorted octahedra comprised of three Xe---O secondary contacts that are approximately trans to the primary Xe–O bonds of XeO<sub>3</sub>. Quantum-chemical calculations were used to assess the Xe---O adduct bonds, which are predominantly electrostatic σ-hole bonds between the nucleophilic oxygen atoms of the bases and the σ-holes of the xenon atoms.


2019 ◽  
Author(s):  
Chem Int

Optically transparent single crystals of potassium acid phthalate (KAP, 0.5 g) 0.05 g and 0.1 g (1 and 2 mol %) trytophan were grown in aqueous solution by slow evaporation technique at room temperature. Single crystal X- ray diffraction analysis confirmed the changes in the lattice parameters of the doped crystals. The presence of functional groups in the crystal lattice has been determined qualitatively by FTIR analysis. Optical absorption studies revealed that the doped crystals possess very low absorption in the entire visible region. The dielectric constant has been studied as a function of frequency for the doped crystals. The thermal stability was evaluated by TG-DSC analysis.


Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1023 ◽  
Author(s):  
Ashish Chhaganlal Gandhi ◽  
Chia-Liang Cheng ◽  
Sheng Yun Wu

We report the synthesis of room temperature (RT) stabilized γ–Bi2O3 nanoparticles (NPs) at the expense of metallic Bi NPs through annealing in an ambient atmosphere. RT stability of the metastable γ–Bi2O3 NPs is confirmed using synchrotron radiation powder X-ray diffraction and Raman spectroscopy. γ–Bi2O3 NPs exhibited a strong red-band emission peaking at ~701 nm, covering 81% integrated intensity of photoluminescence spectra. Our findings suggest that the RT stabilization and enhanced red-band emission of γ‒Bi2O3 is mediated by excess oxygen ion vacancies generated at the octahedral O(2) sites during the annealing process.


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