Hydrate Powder Research Articles

High performance broad band antireflective coatings using a facile synthesis of ink-bottle mesoporous MgF2 nanoparticles for solar applications

Ultra-low refractive index thin films suitable for practical antireflective (AR) applications must be highly transparent, economical, and durable against temperature and weather conditions. In this work, we present a high performance broad band antireflective coating using a facile synthesis of Ink-Bottle mesoporous MgF2 nanoparticles. The nanoparticles having high crystalline and dispersible properties were prepared by a deformation-reformation route from coarse commercial MgF2 hydrate powder by Lyothermal synthesis. These nanoparticles, after dispersion in a suitable solvent were used to develop a single layer AR coating by dip-coating technique. We precisely developed coatings tunable to achieve minimum reflection losses between 400 and 1500nm. The AR coating exhibited nearly 100% transmittance within visible range (615–660nm) and an average transmittance of 99% and 97% in the visible (400–800nm) and active solar range (300–1500nm) respectively. Further, use of the AR coating on PV glass led to a net improvement of 6% in efficiency for c-Si solar cells. This work opens a promising approach to improve the device performance of solar cells as well as solar collectors by developing broad band antireflective surfaces using mesoporous nanoparticles.

Phase transformations, microstructure formation and in vitro osteoblast response in calcium silicate/brushite cement composites

Self-setting simple calcium silicate/brushite (B) biocements with various Ca/P ratios were prepared by mutual mixing of both monocalcium silicate hydrate (CSH) or β-wollastonite (woll) powders with B and the addition of 2 wt% NaH2PO4 solution as a hardening liquid. The phase composition of the final composites and the texture of the surface calcium phosphate/silica layer were controlled by the starting Ca/P ratio in composites and the pH during setting. It was verified that the presence of continuous bone-like calcium phosphate coating on the surface of the samples was not essential for in vitro osteoblast proliferation. The nanocrystalline calcium deficient hydroxyapatite and amorphous silica were found as the main setting products in composite mixtures with a Ca/P ratio close to the region of the formation of deficient hydroxyapatite-like calcium phosphates. No CSH phase with a lower Ca/Si ratio was identified after transformation. The results confirmed a small effect of the monocalcium silicate addition on the compressive strength (CS) of cements up to 30 wt% (around 20–25 MPa) and a significant rise of the value in 50 woll/B cement (65 MPa). The final setting times of the cement composites varied between 5 and 43 min depending on the P/L ratio and the type of monocalcium silicate phase in the cement mixture. 10CSH/B and 50 woll/B cements with different textures but free of both the needle-like and perpendicularly-oriented hydroxyapatite particles on the surface of the samples had low cytotoxicity.

Influence of production parameters on gas hydrate and ice powder pelletizing

A lab scale twin roll press machine was developed for pelletizing natural gas hydrate powder. Ice and hydrate powder were used for the pellet extrusion system. The effects of feeding pressure, pressure ratio, and rotating speed of the twin roll were investigated for producing high strength and stiffness hydrate pellets. The compressive strength and stiffness of pellet increased with increasing feeding pressure and rotation speed. In particular, there was a relatively large increase in the stiffness with an increase in rotating speed, and a relatively large increase in strength with increasing feeding pressure. The production ratio of pellets largely depended on the rotating speed of the twin roll. The results indicate the promising future of solid transportation of natural gas.

Gas hydrate powder formation – Ultimate solution in natural gas flow assurance

Gas hydrates may plug hydrocarbon flowlines even at low hydrate volume fraction due to agglomeration. Anti-agglomeration is perhaps the most effective approach for flow assurance. An effective anti-agglomerant (AA) can prevent gas hydrate particles from sticking together by lowering of the water–oil interfacial tension and increase of the contact angle of water on hydrate surface. In a recent work, we have introduced a new AA formulation which is effective; it forms hydrate slurry over a broad range of oil to water ratio. In this study, we introduce a modified chemical formulation effective at extreme conditions when hydrate powders are formed from two different gases. The formation of hydrate powders has not been reported in the literature. The powders flow readily in rocking cells. The hydrate fraction can be as high as 95% with fluidity behavior. The AA effectiveness reported in this study is much higher than the past work. A new anti-agglomeration mechanism is also proposed. The gas hydrate powder formation may have applications not only in flow assurance, but also in energy storage.

Spin Coating Deposition of <i>c</i>-Oriented Wurtzite Gallium Nitride Thin Film

Spin coating growth and characterisations of c-oriented wurtzite structure gallium nitride (GaN) thin film on silicon (Si) substrate with (100) orientation was reported. The precursor solution consisted of a readily available gallium (III) nitrate hydrate powder, ethanol and diethanolamine as starting material, solvent and surfactant. All the structural and optical results showed that c-oriented wurtzite GaN thin film was deposited on Si (100) substrate. Compared with earlier reported work using sol-gel deposition, significant improvements in the structural quality of the GaN thin film were observed. The FWHM value of the thin film was approximately 2.60°. The framework described here is both an easy in setup and simple method as compared to other method such as MBE, MOCVD, and radio frequency sputtering to produce c-oriented wurtzite structure GaN thin film.

Hydrogen titanium oxide hydrate: excellent performance on degradation of methyl blue in aqueous solutions

Nanotube-assembled flower-like hydrogen titanium oxide hydrate (H2Ti2O4(OH)2), which has degradation capacity for methyl blue (MB) even in darkness, was prepared via a microwave solvothermal process. Physicochemical features of the hydrogen titanium oxide hydrate powders were characterized by X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, Fourier transform-infrared spectroscopy and UV/VIS/NIR spectrometry. The degradation of methyl blue (MB), methyl orange (MO) and Rhodamine B (Rhb) solution with a water-cooling system was carried out to study the photocatalytic properties of the powders. Results indicate that the H2Ti2O4(OH)2 has excellent performance on degradation of MB, which can be attributed to the hydroxyl group (–OH) from the surface of the catalysts confirmed by electron spin resonance signals (ESR). Furthermore, the intensity of ESR signals rapidly increased with the irradiation time and did not reach maximum after 11 min, which indicated that the photogenerated holes in the valence band of H2Ti2O4(OH)2 catalysts reacted rapidly with surface-bound water or the hydroxyl group and produced a large amount of ˙OH, which was beneficial for degrading MB. The degradation results indicate that these catalysts have potential uses in removing harmful carcinogens from water, in addition to possible applications in reducing the harmful effects of oil spills.

All-Solid-State Thin-Film Electrochemical Capacitors Using Inorganic Nanosheets Electrolytes

Introduction These days, demands of safe, inexpensive and large-capacity energy storage devices are increasing for various applications as power sources of electrical vehicles. All-solid-state thin-film electrochemical capacitors using protons as carriers can meet such demands. However, solid-state electrolytes have large electrolyte resistance and interfacial resistance between electrolytes and electrodes, which cause depression of powers and energy densities of electrochemical capacitors. In this study, we focused on extremely thin nanosheets, which are plate-like particles with thicknesses of only a few nanometers. Electrolyte resistance was reduced by applying thin-films of stacked nanosheets to electrolytes. Also, all-solid-state thin-film electrochemical capacitors were fabricated, and evaluated by electrochemical measurements. As the proton conducting nanosheet, we selected a-zirconium hydrogenphosphate monohydrate (α-Zr(HPO4)2·H2O : ZrP), composed of naturally abundant elements. Experimental ZrP powders were prepared from zirconium oxide hydrate (ZrO2·nH2O) powders through treating with phosphoric acid by hydrothermal synthesis method. A colloidal suspension of ZrP nanosheets was obtained by exfoliation of ZrP powders induced by shaking with aqueous solution of tetrabutylammonium hydroxide. ZrP films were prepared by applying concentrated colloidal suspension of ZrP nanosheets on substrates and drying them in air. Protonic conductivities of ZrP films were measured by alternating-current impedance measurement in the frequency range from 1 MHz to 100 Hz with an applied voltage of ±100 mV. All-solid-state thin-film electrochemical capacitors were fabricated with ruthenium oxide hydrate (RuO2·nH2O : RuO2) as both electrodes and ZrP films as electrolytes. Galvanostatic charge/discharge tests were carried out in the cell voltage range of 0 – 1 V at a constant current density of 100 mA g− 1. Results & Discussions Fig. 1shows protonic conductivities of the ZrP film at relative humidity (R. H.) 90% and those of the ZrP tablet at saturated vapor [1]. The thickness of the ZrP film was 700 nm. Protonic conductivity of the ZrP film increased as with increasing temperature, and reached 3.2×10−6 Scm−1 at 80oC. The activation energy of protonic conduction in the ZrP film was 0.28 eV. This value is close to the activation energy of the ZrP tablet (0.25 eV) [1], and this suggests that the mechanism of protonic conduction in ZrP films is the same to that in ZrP tablets. The thickness of the ZrP film was over one thousand times smaller than that of the ZrP tablet (1 mm), so the areal electrolyte resistance could be reduced from 1.0×105 Ωcm2 (ZrP tablet at 27oC, R. H. 90%) [2] to 1.0×102 Ωcm2 (ZrP film at 30oC, R. H. 90%). Fig. 2 shows the charge and discharge curves of the all-solid-state thin-film electrochemical capacitor (RuO2|ZrP-film|RuO2) measured at a constant current density of 100 mA g−1. No recognizable plateau regions are observed in either the charge or the discharge curves. The electrochemical capacitor exhibited a reversible capacity of 22 mAh g−1 at the 10th cycle. This capacity is much higher than that of many other proton conducting all-solid-state capacitors [3, 4], and is comparable to those of electrochemical capacitors assembled with liquid electrolytes. In addition, the cycle characteristic was good and coulombic efficiency was high (h = 93%), suggesting the influences of side reactions to be small.

The dry process of ZnO film deposition by atmospheric pressure plasma

An atmospheric pressure plasma system has been developed to prepare zinc oxide (ZnO) thin film on the silicon substrate. The precursor of dry powder of Zinc acetylacetonate hydrate was directly sublimated as vapor and carried by Argon into the downstream of Nitrogen plasma jet. The films deposition process was carried out at low temperature and the substrate temperature was not over 300 oC. The examinations of thin film sample by X-ray diffraction (XRD) showed the major peak at 34o was the hexagonal wurtzite structure of ZnO. The surface morphologies and thickness of the films were evaluated by scanning electron microscopy (SEM). The mean square surface roughness of the ZnO film was only 4.063 nm and a smooth surface of ZnO thin film was obtained.

Synthesis And Characterization Of Fe4[Co(CN)6]3.16H2O/SiO2 nano-composites By Coprecipitation Method

Nano-dimensional powder of iron cobalt cyanide hydrate in silica matrix (member of Prussian-blue family) was obtained using ferric chloride, cobalt chloride, potassium cyanide and silica in their dilute solution through coprecipitation method. The crystal structures and surface morphology of nanoparticles were characterized by the powder X-Ray diffraction (XRD) and transmission electron microscopy (TEM). The formation of compound Fe4 (Co(CN)6)3.16H2O was revealed by Fourier transform infrared (FTIR) spectroscopy. The magnetic properties of prepared samples were measured at room temperature using a Vibrating sample magnetometer (VSM). Effect of the thermal annealing on the phase decomposition and phase evolution of prepared samples for different temperature and time duration has been discussed. The results showed that the structure, phase and shape of the nanocrystallite are strongly influenced by the sintering temperature and time period. Results also showed that direct phase transition from Fe4 (Co (CN)6)3.16H2O to CoFe2O4 occurred at temperature 300 0 C (2h). The shape of embedded CoFe2O4 (a final product) in silica matrix is almost spherical and its average size ranges 15-25 nm. Copyright © 2013 VBRI press.

Characterisation of large scale structures in starch granules via small-angle neutron and X-ray scattering

Small angle scattering (SAS) techniques have a distinguished track record in illuminating the semi-crystalline lamellar structure of the starch granule. To date, there have been few attempts to use SAS techniques to characterise larger-scale structures reported from imaging techniques such as growth rings, blocklets or pores, nor how these structures would modulate the well-known scattering arising from the semi-crystalline lamellar structure. In this study, SAS data collected over an extended q range were gathered from dry and hydrated starch powders from varied botanical sources. The use of neutrons and X-rays, as well as comparing dry and hydrated granules, allowed different levels of contrast in scattering length density to be probed and therefore selected structural regions to be highlighted. The lowest q range, 0.002–0.04Å−1, was found to be dominated by scattering from the starch granules themselves, especially in the dry powders; however an inflection point from a low contrast structure was observed at 0.035Å−1. The associated scattering was interpreted within a unified scattering framework with the inflexion point correlating with a structure with radius of gyration ∼90Å – a size comparable to small blocklets or superhelices. In hydrated starches, it is observed that there is an inflection point between lamellar and q−4 power-law scattering regions at approximately 0.004Å−1 which may correlate with growth rings and large blocklets. The implications of these findings on existing models of starch lamellar scattering are discussed.

미세직경 얼음을 이용한 CO2하이드레이트 제조특성 연구

가스 하이드레이트는 순수한 물이 이루는 격자구조 내에 다양한 가스분자들이 선택적으로 포획되어진 고체상의 화합물로, 최근 이산화탄소를 포집, 수송, 저장 하는 CCS (Carbon Capture and Storage)기술에 이를 응용하려는 연구가 활발히 진행되고 있다. 가스 하이드레이트를 적용한 CCS 기술의 핵심은 효과적으로 <TEX>$CO_2$</TEX> 하이드레이트를 제조하는 기법의 개발이며, 본 연구에서는 초음파 노즐을 이용하여 수십 나노미터 직경의 미세수적을 통해 고속의 <TEX>$CO_2$</TEX> 하이드레이트 제조기술 개발하였고, 이 과정의 특성을 파악해 보았다. 주파수 2.4 MHz의 초음파 노즐을 이용하여 미세직경의 수적을 분무하고 이송가스(carrier gas)로 <TEX>$CO_2$</TEX>를 적용, 미세 수적과 <TEX>$CO_2$</TEX>가 동시에 급속 냉각되는 저온 반응기에 도입되어 다공질 얼음입자가 직접 평균 <TEX>$10.7{\mu}m$</TEX> 직경의 <TEX>$CO_2$</TEX> 하이드레이트로 생성되는 연속공정을 개발하였다. 미세직경 얼음입자를 시작물로 하여 정압조건에서 <TEX>$CO_2$</TEX> 하이드레이트가 생성되도록 하며 가스포집량을 측정, 그의 가스 포집속도를 알아본 결과, 미세직경이며 동시에 다공 얼음이 제공하는 높은 기-고 접촉면적으로 인해 가스 하이드레이트 생성에 매우 적합한 것을 알 수 있었으며, 제조된 <TEX>$CO_2$</TEX> 하이드레이트의 자기보존효과(self-preservation effect)를 실험으로 확인함으로서 <TEX>$CO_2$</TEX> 가스의 수송에도 이용 가능함을 알 수 있었다. Gas hydrate is an inclusion compound consisting of water and low molecular weight gases, which are incorporated into the lattice structure of water. Owing to its promising aspect to application technologies, gas hydrate has been widely studied recently, especially <TEX>$CO_2$</TEX> hydrate for the CCS (Carbon Capture and Storage) issue. The key point of <TEX>$CO_2$</TEX> hydrate technology for the CCS is how to produce gas hydrate in an efficient and economic way. In this study, we have tried to study the characteristic of gas hydrate formation using micro-sized ice through an ultrasonic nozzle which generate 2.4 MHz frequency wave. <TEX>$CO_2$</TEX> as a carrier gas brings micro-sized mist into low-temperature reactor, where the mist and carrier gas forms <TEX>$CO_2$</TEX> hydrate under <TEX>$-55^{\circ}C$</TEX> and atmospheric pressure condition and some part of the mist also remains unreacted micro-sized ice. Formed gas hydrate was average 10.7 of diameter at average. The starting ice particle was set to constant pressure to form <TEX>$CO_2$</TEX> hydrate and the consumed amount of <TEX>$CO_2$</TEX> gas was simultaneously measured to calculate the conversion of ice into gas hydrate. Results showed that the gas hydrate formation was highly suitable because of its extremely high gas-solid contact area, and the formation rate was also very high. Self-preservation effect of <TEX>$CO_2$</TEX> hydrate was confirmed by the measurement of <TEX>$CO_2$</TEX> hydrate powder at normal and at pressed state, which resulted that this kind of gas storage and transport could be feasible using <TEX>$CO_2$</TEX> hydrate formation.

About transformation of the deep-water methane bubbles into hydrate powder and hydrate foam

During the Russian Academy of Sciences “MIRI na Baikale, 2008–2010” expedition, deep-water experiments with the bubbles of methane seeping from the bottom at depths 405, 860 and 1400 meters were carried out. These depths correspond to gas hydrate stability zone. Bubbles were caught by the trap which was looked like an inverted glass. It was found that the behavior of bubbles in a trap depends on the depth. At depth of 405 meters formation of hydrates was not observed. Having got to a trap at the depth of 860 meters, bubbles became covered by solid hydrate envelope, kept the initial form, and after a time period collapsed in a number of hydrate fragments which showed all properties of a granular matter. No visible changes in the hydrate granular matter were observed in the course of lifting it to a depth of 380 meters. Shallower, the decomposition of the hydrate granular matter into methane gas was observed. In the experiments at depth of 1400 meters the caught bubbles, becoming covered by hydrate envelope formed solid hydrate foam in the trap. At lifting this foam structure was deformed slightly but simultaneously a free gas left the foam and filled the trap. The volume of free gas in the trap at lifting varied according to the Boyle-Mariotte law.

Breakup of deep-water methane bubbles

During the Russian Academy of Sciences “MIRI na Baikale. 2008–2009” expedition, deep-water experiments on methane bubbles emerging from the lake bottom at depth of 1400 and 860 meters were carried out. Bubbles escaping the seabed were caught by a trap, which was an inverted glass. Entering in the trap, bubbles became covered by a gas hydrate envelope and then after a time period collapsed into a number of gas hydrate solid fragments. Due to positive buoyancy, fragments remained in the top part of a trap, exhibiting properties of a powder. The glass’s bottom was replaced with a 1 mm mesh grid, allowing the finest gas hydrate particles to sift through the grid, rising upwards. It is proposed that bubble collapse into fragments is related to the pressure drop in the bubble in the course of formation of the gas hydrate envelope. No visible changes in the gas hydrate powder were observed in the course of lifting it to a depth of 380 meters. Shallower than 380 meters, i.e., outside the zone of gas hydrate stability, decomposition of the gas hydrate powder into methane gas was observed.

Dynamics of apoB100-Containing Lipoproteins Determined by Incoherent Elastic Neutron Scattering

Apolipoprotein B100 (apoB100)-containing lipoproteins (very low density lipoprotein (VLDL) and low density lipoprotein (LDL)) are the principal fat and cholesterol carriers in blood. During metabolic conversion from VLDL to LDL, the particle size decreases (from ∼ 80 nm to 20 nm) and lipid composition is changed, however, the amphiphilic apoB100 molecule remains bound to its lipoprotein particle and most likely compensates for structural changes due to its inherent conformational flexibility and dynamics .Here, we report on motions in the time range of 100 ps to 1 ns in human-LDL, human VLDL and yolk-VLDL, which were recorded by elastic neutron-scattering temperature scans from 20K to 310 K using hydrated lipoprotein powders. The mean square displacement values were calculated from the scattering vector dependence of the elastic intensity I(Q). The effective force constants , which are a measure for the resilience of the particle, were derived from the slopes in the vs. T scans. In the low-temperature harmonic regime we found no substantial differences between lipoprotein fractions ( ∼1 N/m). Nevertheless, lipoproteins are softer compared to hydrated myoglobin powder (2 N/m) or purple membranes (1.7 N/m) [1]. Significant differences were observed with increasing temperatures. Both, human and yolk VLDL show two breaks in the scan with a steep increase in above 270K, whereas LDL shows a smooth behavior above a dynamic transition around 220K. Accordingly, at physiological temperatures VLDL-fractions are highly soft and mobile ( ∼0.08 N/m) as compared to LDL ( ∼ 0.2 N/m). Sucrose, added as cryoprotectant, significantly modified the dynamics of VLDL, as it confers extreme stability to VLDL over the whole temperature range and substantially suppresses dynamic transitions.[1] G. Zaccai, Science 288 (2000), 1604-1607

On the behaviour of water hydrogen bonds at biomolecular sites: Dependences on temperature and on network dimensionality

Neutron scattering experiments have been used to investigate the effects of temperature and network dimensionality (from hydrated powders to highly concentrated solutions) on the hydrogen bond dynamics of hydration water molecules at specific sites in selected biomolecules. With this aim in view, the evolution of hydration water dynamics of a prototypical hydrophobic amino acid with polar backbone, N-acetyl-leucine-methylamide (NALMA), and a hydrophilic amino acid, N-acetyl-glycine-methylamide (NAGMA), has been investigated as a function of temperature. We show that the temperature dependence of the diffusive dynamics of water molecules is the same for both hydrophilic and hydrophobic peptides. A comparison between hydrated powders and high concentrated solutions reveals a similar behaviour, particularly for the hydrophobic peptide. On the other hand we find a distinct difference in the behaviour with temperature of the hydrogen bond lifetime in solutions and hydrated powders. Whereas at room temperature the hydrogen bond lifetime is longer in solution than in the hydrated powder, the reverse situation obtains at low temperatures. This result suggests a change in the plasticity of the hydrogen bond network depending on its extension. Differences in the densities of states lend support to this concept.

Compressive strength of ice-powder pellets as portable media of gas hydrate

This paper provides experimental results from an investigation to assess the compressive strength of ice-powder pellets for potential use as a solid form of gas hydrate. The mechanical strength of the pellets is one of the key parameters in designing a cost effective storage system, as well as transportation carrier ships and re-gasification processes, because the amount of BOG (boil off gas) is directly related to the size of the storage tank, the pellet size, and the shape and permeability of the pellets. Ice powder, being a convenient substitute for hydrate powder, can be fabricated into cylindrical and capsule-type shaped pellets, and the resulting mechanical strength, in terms of the stackable height, has been measured for different press forces. A procedural verification of producing and testing the ice pellets suggests some useful insights for deciding the porosity, size and shape of the pellet designs for realizing a portable media for natural gas hydrates.

Polypropylene ionic thermoplastic elastomers: Synthesis and properties

Polypropylene ionic thermoplastic elastomers have been prepared by melt radical grafting of maleic anhydride onto polypropylene in the presence of N-bromosuccinimide followed by neutralization of the resulting elastomeric grafted polypropylene using sodium salts. Sodium hydroxide and sodium acetate were compared in aqueous solution, as anhydrous or hydrated powders. The neutralization reaction was followed by Fourier transform infrared spectroscopy, allowing the development of a method to determine the effective neutralization degree. Important physical changes were recorded upon neutralization. Especially thermal stability, shear storage modulus and complex viscosity in the flow region were largely increased as a function of the neutralization degree.

The impact of hydration water on the dynamics of side chains of hydrophobic peptides: From dry powder to highly concentrated solutions

Elastic and quasielastic neutron scattering experiments are used to investigate the dynamics of side chains in proteins, using hydrophobic peptides, from dry and hydrated powders up to solutions, as models. The changes of the internal dynamics of a prototypical hydrophobic amino acid, N-acetyl-leucine-methylamide, and alanine amino acids are investigated as a function of water/peptide molecular ratio. While previous results have shown that, in concentrated solution, when the hydrophobic side chains are hydrated by a single hydration water layer, the only allowed motions are confined and can be attributed to librational/rotational movements associated with the methyl groups. In the present work we observe a dynamical evolution from dry to highly hydrated powder. We also observe rotational and diffusive motions and a dynamical transition at approximately 250 K for long side chain peptides while for peptides with short side chains, there is no dynamical transition but only rotational motions. With a local measurement of the influence of hydration water dynamics on the amino acid side chains dynamics, we provide unique experimental evidence that the structural and dynamical properties of interfacial water strongly influence the side chain dynamics and the activation of diffusive motions. We also emphasize that the side chain length has a role on the onset of dynamical transition.

Visible light photocatalysis by a Titania–Rhodium(III) complex

Titania hybrid photocatalysts containing 0.5, 1.0, 2.0, and 5.0 wt% of rhodium(III) were prepared by chemisorption of RhCl 3 × 3H 2O onto anatase hydrate powder (TH). Analytical data suggest that a titania–trichlororhodate complex is produced containing a [TiO 2]–O–Rh bond. Similar results are found in the case of modification by RhBr 3 × 3H 2O. Diffuse reflectance spectra exhibit an absorption shoulder throughout the visible region down to 700 nm. Photoelectrochemical measurements indicate that the quasi-Fermi level of electrons is gradually shifted to more anodic potentials with increasing rhodium loading reaching a value of −0.34 V at pH 7 (vs. NHE) in the case of 5.0%RhCl 3/TH. This is more anodic by 210 mV as compared to unmodified TH. Upon visible light irradiation this photocatalyst induces a fast mineralization of 4-chlorophenol whereas cyanuric acid, which is known to be mineralized in the presence of the analogous Pt(IV) modified titania, is not degraded.

Efficient storage of hydrogen fuel into leaky cages of clathrate hydrate

We demonstrate an alternative principle to efficiently store molecular hydrogen fuel into clathrate hydrate medium. Hydrogen-free hydrate powders quickly absorb the hydrogen gas at moderate pressure appropriate for industrial applications. The absorption kinetics was observed in situ by nuclear magnetic resonance (NMR) spectroscopy in a pressurized tube. The diffusion of hydrogen through the solid hydrate medium was directly measured by pulsed field gradient NMR. At temperatures down to 250K, the stored hydrogen is still mobile so that the hydrate storage should work well even in cold environments.