An understanding of water’s anomalies is closely linked to an the phase diagram metastable noncrystalline states. Despite considerable effort, such has remained elusive and many puzzles regarding transitions in supercooled liquid water their possible amorphous proxies at low temperatures remain. Here, decompression very high density ice (VHDA) from 1.1to0.02GPa 140K studied by means dilatometry powder x-ray diffraction quench-recovered It shown that three states are reversibly connected each...

We here report differential scanning calorimetry (DSC) scans recorded by repeatedly heating the H(2)O (D(2)O) low density amorph (LDA) which was made isothermal decompression of very high-density amorphous ice (VHDA) at 140 K from 1.1 to 0.006 GPa. These DSC show a glass --> liquid transition endotherm with an onset temperature (T(g)) approximately 137 (140) rate 30 min(-1) accompanied increase in heat capacity 1.7 (1.5) J K(-1) mol(-1). establish reversibility this effect thermally cycling...

Dilatometry experiments on low- and high-density amorphous ices up to 0.30 GPa are presented together with powder x-ray diffraction data. Repeated isobaric heating cooling cycles reveal three competing processes: irreversible (micro)structural relaxation, reversible (irreversible) crystallization. The third subsequent runs produce identical curves, i.e., relaxation is absent. We interpret the deviation from linear expansivity in these curves as onset temperature of volumetric glass-to-liquid...

We have recently observed amorphous–amorphous transitions incurred upon decompressing very high density amorphous ice (VHDA) at 140 K from 1.1 to <0.02 GPa in a piston–cylinder setup by monitoring the piston displacement as function of pressure and taking powder x-ray diffractograms quench-recovered samples (Winkel et al 2008 J. Chem. Phys. 128 044510). Here we study effect changing temperature 77 160 during decompression GPa, substituting D2O for H2O 143 K. At all structural are arrested...

We report the isotropic etching of 2D and 3D polystyrene (PS) nanosphere hcp arrays using a benchtop O2 radio frequency plasma cleaner. Unexpectedly, this slow allows tuning both particle diameter shape. Due to suppressed rate at point contact between PS particles originating from their arrangement in crystals, spherical templates are converted into polyhedral structures with well-defined hexagonal cross sections directions parallel normal crystal c-axis. Additionally, we found that located...

Amorphous and graphitized nitrogen-doped (N-doped) carbon spheres are investigated as structurally well-defined model systems to gain a deeper understanding of the relationship between synthesis, structure, their activity in oxygen reduction reaction (ORR). N-doped were synthesized by hydrothermal treatment glucose solution yielding with sizes 330 ± 50 nm, followed nitrogen doping via heat ammonia atmosphere. The influence a) varying temperature (550-1000 °C) b) catalytic graphitization...

Anisotropy is a key factor regarding mechanical or transport properties and thus the functionality of porous materials. However, ability to deliberately design pore structure hierarchically organized networks toward anisotropic features limited. Here, we report two straightforward routes structured carbon monoliths with an alignment microstructure on level macro- mesopores. One approach based nanocasting (NC) precursors into hierarchical silica hard templates. The second route, direct...

Nanoporous carbon materials with customized structural features enable sustainable and electrochemical applications through improved performance efficiency. Carbon spherogels (highly porous aerogel consisting of an assembly hollow nanosphere units uniform diameters) are desirable candidates as they combine exceptional electrical conductivity, bespoke shell porosity, tunability the thickness, a high surface area. Herein, we introduce novel more environmentally friendly sol-gel synthesis...

This study presents a novel approach to developing high-performance lithium-ion battery electrodes by loading titania-carbon hybrid spherogels with sulfur. The resulting materials combine high charge storage capacity, electrical conductivity, and core-shell morphology, enabling the development of next-generation electrodes. We obtained homogeneous carbon spheres caging crystalline titania particles sulfur using template-assisted sol-gel route carefully treated titania-loaded hydrogen...

Using soft templating, mechanically reversible compressible resorcinol–formaldehyde aerogels can be converted into carbon with high surface area by carbonization in an inert atmosphere.

We study the density-driven phase transition from hexagonal ice in temperature range of 170--230 K up to pressures 0.65 GPa using a piston-cylinder apparatus. Pure II, pure III, or mixtures II and III are identified as products when compression-rate is varied 0.001--4 GPa/min. At low compression-rates at high temperatures, formation observed, which accordance with diagram. However, temperatures higher compression rates, metastable extends known for possible III. Metastable rather than stable...

Structural hierarchy, porosity, and isotropy/anisotropy are highly relevant factors for mechanical properties thereby the functionality of porous materials. However, even though anisotropic hierarchically organized, materials well known in nature, such as bone or wood, producing synthetic counterparts laboratory is difficult. We report first time a straightforward combination sol–gel processing shear-induced alignment to create hierarchical silica monoliths exhibiting anisotropy on levels...

Two hierarchically organized carbon materials with an inverse mesopore structure were synthesized. Their nanostructure is either composed of hexagonally packed nanofibers (nanocast carbon) or cylindrical nanopores arranged on a hexagonal lattice (soft-templated carbon). Micropores subsequently introduced by CO2 activation concomitant increase in specific surface area. All characterized regarding their using electron microscopy, gas adsorption, X-ray diffraction, and small-angle scattering....

Abstract As a result of the global demand for sustainable products, suitable alternative to resorcinol-formaldehyde aerogels, which are frequently used as precursors carbon is searched for. In this study, replacement petroleum-derived formaldehyde with natural, biobased crosslinker, namely 5-(hydroxymethyl)furfural (5-HMF) shown, and synthesis renewable, monolithic tannin aerogels demonstrated. Compared well-known tannin-formaldehyde green shows lower reactivity crosslinker associated...

We present a versatile strategy to tailor the nanostructure of monolithic carbon aerogels. By use an aqueous colloidal solution polystyrene in sol-gel processing resorcinol-formaldehyde gels, we can prepare, after supercritical drying and successive carbonization, freestanding aerogels, solely composed interconnected uniformly sized hollow spheres, which name spherogels. Each sphere is enclosed by microporous wall whose thickness be adjusted concentration, affects pore texture as well...

This study presents a direct application for freestanding and monolithic carbon spherogels, which are highly porous aerogels solely composed of hollow nanospheres, as binder-free electrode materials supercapacitors. By applying polystyrene nanospheres templating agents in the size range 277–907 nm concentrations from 1.5 to 12 wt % sol–gel polymerization process resorcinol–formaldehyde, we can distinctly tailor spheres' pore arrangement thickness microporous walls. Furthermore, required...

We report a novel method of detecting the glass --> liquid transition at high pressures, which comprises measuring relative volume change incurred upon heating glassy samples into state. show data on glycerol in pressure range 0.050-1.00 GPa to demonstrate viability method. The reversible is observed by means kink sample isobarically, attributed temperature Tg. This can only be second and subsequent cycles since it superposed compaction first cycle. isobaric thermal expansivity beta, closely...

A promising route to monolithic, hollow sphere carbon assemblies based on sustainable precursors with a tailored nanostructure is presented. These assemblies, recently termed spherogels, are generated via polystyrene template-based sol-gel process of mimosa tannin and biomass-derived 5-(hydroxymethyl)furfural. By completely replacing petroleum-based (especially toxic formaldehyde) highly porous, nanoscale monoliths obtained, which investigated as state-of-the-art, electrode materials for...

Tannin-furanic foams are a promising and biogenic alternative to oil-based porous materials. Their hydrophilic character, typically indicated by contact angle water of 70°, limits some potential applications (for instance outdoor thermal insulation). To overcome this, post-synthetic surface modification step with different fluorine-free organosilanes at 323 K was investigated focus on the final, hydrophobic performance. On one side, methyltrimethoxysilane, 3-(chloropropyl)trimethoxysilane,...