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The mechanical properties of olivine-rich rocks are key to determining the mechanical coupling between Earth’s lithosphere and asthenosphere. In crystalline materials, the motion of crystal defects is fundamental to plastic flow 1 – 4 . However, because the main constituent of olivine-rich rocks does not have enough slip systems, additional deformation mechanisms are needed to satisfy strain conditions. Experimental studies have suggested a non-Newtonian, grain-size-sensitive mechanism in olivine involving grain-boundary sliding 5 , 6 . However, very few microstructural investigations have been conducted on grain-boundary sliding, and there is no consensus on whether a single or multiple physical mechanisms are at play. Most importantly, there are no theoretical frameworks for incorporating the mechanics of grain boundaries in polycrystalline plasticity models. Here we identify a mechanism for deformation at grain boundaries in olivine-rich rocks. We show that, in forsterite, amorphization takes place at grain boundaries under stress and that the onset of ductility of olivine-rich rocks is due to the activation of grain-boundary mobility in these amorphous layers. This mechanism could trigger plastic processes in the deep Earth, where high-stress conditions are encountered (for example, at the brittle–plastic transition). Our proposed mechanism is especially relevant at the lithosphere–asthenosphere boundary, where olivine reaches the glass transition temperature, triggering a decrease in its viscosity and thus promoting grain-boundary sliding. Amorphization at grain boundaries in olivine-rich rocks under stress and consequent grain-boundary sliding could explain the decrease in viscosity between the lithosphere and the asthenosphere.

This paper examines the effect of mechanical activation on the amorphization of starch having different types of crystalline structure (A-type corn starch; B-type potato starch; and C-type tapioca starch). Structural properties of the starches were studied by X-ray diffraction analysis. Mechanical activation in a planetary ball mill reduces the degree of crystallinity in proportion to pretreatment duration. C-type tapioca starch was found to have the highest degree of crystallinity. Energy consumed to achieve complete amorphization of the starches having different types of crystalline structure was measured. The kinetic parameters of the process (the effective rate constants) were determined. The rate constant and the strongest decline in the crystallinity degree after mechanical activation change in the following series: C-type starch, A-type starch, and B-type starch.

Amorphization technology has been the subject of continuous attention in the pharmaceutical industry, as a means to enhance the solubility of poorly water-soluble drugs. Being in a high energy state, amorphous formulations generally display significantly increased apparent solubility as compared to their crystalline counterparts, which may allow them to generate a supersaturated state in the gastrointestinal tract and in turn, improve the bioavailability. Conventionally, hydrophilic polymers have been used as carriers, in which the amorphous drugs were dispersed and stabilized to form polymeric amorphous solid dispersions. However, the technique had its limitations, some of which include the need for a large number of carriers, the tendency to recrystallize during storage, and the possibility of thermal decomposition of the drug during preparation. Therefore, emerging amorphization technologies have focused on the investigation of novel amorphous-stabilizing carriers and preparation methods that can improve the drug loading and the degree of amorphization. This review highlights the recent pharmaceutical approaches utilizing drug amorphization, such as co-amorphous systems, mesoporous particle-based techniques, and in situ amorphization. Recent updates on these technologies in the last five years are discussed with a focus on their characteristics and commercial potential.

The nature of amorphous ices has been debated for more than 35 years. In essence, the question is whether they are related to ice polymorphs or to liquids. The fact that amorphous ices are traditionally prepared from crystalline ice via pressure-induced amorphization has made a clear distinction tricky. In this work, we vitrify liquid droplets through cooling at ≥10⁶ K · s−1 and pressurize the glassy deposit.We observe a first order–like densification upon pressurization and recover a high-density glass. The two glasses resemble low- and high-density amorphous ice in terms of both structure and thermal properties. Vitrified water shows all features that have been reported for amorphous icesmade from crystalline ice. The only difference is that the hyperquenched and pressurized deposit shows slightly different crystallization kinetics to ice I upon heating at ambient pressure. This implies a thermodynamically continuous connection of amorphous ices with liquids, not crystals.

Pursuing active and durable water splitting electrocatalysts is of vital significance for solving the sluggish kinetics of the oxygen evolution reaction (OER) process in energy supply. Herein, theoretical calculations identify that the local distortion-strain effect in amorphous RuTe 2 system abnormally sensitizes the Te-pπ coupling capability and enhances the electron-transfer of Ru-sites, in which the excellent inter-orbital p-d transfers determine strong electronic activities for boosting OER performance. Thus, a robust electrocatalyst based on amorphous RuTe 2 porous nanorods (PNRs) is successfully fabricated. In the acidic water splitting, a-RuTe 2 PNRs exhibit a superior performance, which only require a cell voltage of 1.52 V to reach a current density of 10 mA cm −2 . Detailed investigations show that the high density of defects combine with oxygen atoms to form RuO x H y species, which are conducive to the OER. This work offers valuable insights for constructing robust electrocatalysts based on theoretical calculations guided by rational design and amorphous materials. Elctrochemical water splitting is of vital significance for energy conversion and storage. Here the authors show an electrocatalyst based on amorphous ruthenium-tellurium porous nanorods which exhibit significantly improved OER performance than its crystalline counterparts

Water splitting catalysed by earth-abundant materials is pivotal for global-scale production of non-fossil fuels, yet our understanding of the active catalyst structure and reactivity is still insufficient. Here we report on the structurally reversible evolution of crystalline Co 3 O 4 electrocatalysts during oxygen evolution reaction identified using advanced in situ X-ray techniques. At electrode potentials facilitating oxygen evolution, a sub-nanometre shell of the Co 3 O 4 is transformed into an X-ray amorphous CoO x (OH) y which comprises di-μ-oxo-bridged Co 3+/4+ ions. Unlike irreversible amorphizations, here, the formation of the catalytically-active layer is reversed by re-crystallization upon return to non-catalytic electrode conditions. The Co 3 O 4 material thus combines the stability advantages of a controlled, stable crystalline material with high catalytic activity, thanks to the structural flexibility of its active amorphous oxides. We propose that crystalline oxides may be tailored for generating reactive amorphous surface layers at catalytic potentials, just to return to their stable crystalline state under rest conditions. Understanding of catalyst structure and reactivity is important for the development of water splitting catalysts. Here, the authors report reversible structural transformation of the near-surface of crystalline Co 3 O 4 electrocatalysts to an amorphous CoO x (OH) y during oxygen evolution.

Lithium-sulfur batteries show great potential to achieve high-energy-density storage, but their long-term stability is still limited due to the shuttle effect caused by the dissolution of polysulfides into electrolyte. Herein, we report a strategy of significantly improving the polysulfides adsorption capability of cobaltous oxide by amorphization-induced surface electronic states modulation. The amorphous cobaltous oxide nanosheets as the cathode additives for lithium-sulfur batteries demonstrates the rate capability and cycling stability with an initial capacity of 1248.2 mAh g -1 at 1 C and a substantial capacity retention of 1037.3 mAh g -1 after 500 cycles. X-ray absorption spectroscopy analysis reveal that the coordination structures and symmetry of ligand field around Co atoms of cobaltous oxide nanosheets are notably changed after amorphization. Moreover, DFT studies further indicate that amorphization-induced re-distribution of d orbital makes more electrons occupy high energy level, thereby resulting in a high binding energy with polysulfides for favorable adsorption. Regulating the adsorption behaviour of the polysulfide species is the key to achieving highly stable Li-S batteries. Here, the authors show that amorphization-induced redistribution of d orbitals enable CoO to be a favourable candidate for polysulfide adsorption and conversion.

Electrified solid–liquid interfaces (ESLIs) play a key role in various electrochemical processes relevant to energy 1 – 5 , biology 6 and geochemistry 7 . The electron and mass transport at the electrified interfaces may result in structural modifications that markedly influence the reaction pathways. For example, electrocatalyst surface restructuring during reactions can substantially affect the catalysis mechanisms and reaction products 1 – 3 . Despite its importance, direct probing the atomic dynamics of solid–liquid interfaces under electric biasing is challenging owing to the nature of being buried in liquid electrolytes and the limited spatial resolution of current techniques for in situ imaging through liquids. Here, with our development of advanced polymer electrochemical liquid cells for transmission electron microscopy (TEM), we are able to directly monitor the atomic dynamics of ESLIs during copper (Cu)-catalysed CO 2 electroreduction reactions (CO 2 ERs). Our observation reveals a fluctuating liquid-like amorphous interphase. It undergoes reversible crystalline–amorphous structural transformations and flows along the electrified Cu surface, thus mediating the crystalline Cu surface restructuring and mass loss through the interphase layer. The combination of real-time observation and theoretical calculations unveils an amorphization-mediated restructuring mechanism resulting from charge-activated surface reactions with the electrolyte. Our results open many opportunities to explore the atomic dynamics and its impact in broad systems involving ESLIs by taking advantage of the in situ imaging capability. The development of advanced polymer electrochemical liquid cells for transmission electron microscopy allows direct monitoring of the atomic dynamics of electrified solid–liquid interfaces during copper-catalysed CO 2 electroreduction reactions.

Surface amorphization provides electrocatalysts with more active sites and flexibility. However, there is still a lack of experimental observations and mechanistic explanations for the in situ amorphization process and its crucial role. Herein, we propose the concept that by in situ reconstructed amorphous surface, metal phosphorus trichalcogenides could intrinsically offer better catalytic performance for the alkaline hydrogen production. Trace Ru (0.81 wt.%) is doped into NiPS 3 nanosheets for alkaline hydrogen production. Using in situ electrochemical transmission electron microscopy technique, we confirmed the amorphization process occurred on the edges of NiPS 3 is critical for achieving superior activity. Comprehensive characterizations and theoretical calculations reveal Ru primarily stabilized at edges of NiPS 3 through in situ formed amorphous layer containing bridging S 2 2− species, which can effectively reduce the reaction energy barrier. This work emphasizes the critical role of in situ formed active layer and suggests its potential for optimizing catalytic activities of electrocatalysts. Surface amorphization generally provides electrocatalysts with more active sites and flexibility. Here it is employed in-situ liquid TEM to observe the surface reconstruction on Ru-NiPS3 nanosheets, confirming that the amorphization on the edges of NiPS3 is critical for achieving superior activity.