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Recently, the discovery of superconductivity in compressed electrides offers a promising route toward searching for high superconductivity in a high-pressure community. However, only a few superconducting electrides have been successfully found thus far, thereby limiting the variety of superconducting electride examples. In this work, we performed extensive structure searches on a high-pressure Y-Si system by using CALYPSO structure prediction methodology. Our simulations identified several stable stoichiometries of YSi, YSi2, YSi3, Y5Si3, Y2Si, and Y3Si under high pressure. These structures contain a diversity of structure configurations, including silicon chains, Si3 trilaterals, Si4 quadrilaterals, Si6 hexagons, Si8 rings, a Si4-Si6-Si8 frame, as well as a silicon layer. Remarkably, Y3Si is predicted to be an electride with a superconducting critical temperature (Tc) of ∼11.2 and 14.5 K at 30 and 50 GPa, respectively. These results highlight the role of the electrons at the Fermi surface in determining the superconductivity of predicted structures.

As a prominent platform possessing the properties of superconductivity (SC) and charge density wave (CDW), transition-metal dichalcogenides (TMDCs) have attracted considerable attention for a long time. Moreover, extensive efforts have been devoted for exploring the SC and/or the interplay between SC and CDW in TMDCs in the past few decades. Here, we systematically investigate the electronic properties and structural evolution of 1T-TaSe2 under pressure. With increasing pressure, pressure-induced superconductivity is observed at ∼2.6 GPa. The superconductive transition temperature (Tc) increases with the suppression of the CDW state to the maximum value of ∼5.1 K at 21.8 GPa and then decreases monotonously up to the highest pressure of 57.8 GPa. 1T-TaSe2 transforms into a monoclinic C2/m structure above 19 GPa. The monoclinic phase coexists with the original phase as the pressure is released under ambient conditions and the retainable superconductivity with Tc = 2.9 K is observed in the released sample. We suggest that the retained superconductivity can be ascribed to the retention of the superconductive high-pressure monoclinic phase in the released sample. Our findings demonstrate that both the structure and CDW order are related to the superconductivity of TaSe2.

The design of metal-bearing carbon-based materials with unique structures and intriguing properties is highly desirable in the fields of physics, chemistry, and materials science. Here, within swarm-intelligence structure search and first-principles computations, we uncovered several hitherto unknown sodium carbides (i.e., Na4C, Na3C2, NaC, Na2C3, and NaC2) under high pressure. Intriguingly, the C atom arrangement reveals multiple structure evolution behavior with increased carbon content, from isolated anions in Na4C, tetramers in Na3C2, extended chains in NaC, pentagonal rings in Na2C3, to eventually hexagonal rings in NaC2. Among predicted phases, the superconducting critical temperature Tc of NaC2 could approach ∼42 K at 80 GPa, which is slightly higher than the Tc of 39 K in the highest phonon-mediated superconductivity of MgB2 at ambient pressure. This work offers insights into the reaction of carbides containing alkali metals and paves the way for the future investigation of high superconductivity in metal carbide systems.

Methyl decanoate (MD), methyl-9-decanoate (MD9D), and n-heptane (H) as alternative blends of biodiesel (B) were used to build a detailed chemical kinetic mechanism containing 3,324 components and 11,053 elementary reactions. This condition verifies that the ignition delay time of the detailed mechanism in the experiment conditions is reasonable. MD and MD9D will produce methyl-2-palmitate (MP2D) and finally be dehydrogenated as CH2O. Furthermore, R4 (O + H2O→OH + OH) and R228 (CH2CHO + O2→CH2O + CO + OH) are the key reactions, which will influence the ignition delay and heat release. According to the simulation result, the rate of BH (the volume ratio of the biodiesel/n-heptane mixture is fixed at 20%/80%) in constant volume bomb (Cetane Ignition Delay 510, CID 510) is the highest. However, with the development of ethanol, the rates decreased. The reactors of BHE5 (BHE5 refers to a blend of 5% ethanol and 95% biodiesel/n-heptane) have the highest rate among the ethanol blends. In addition, the reaction rate of the intermediate substance of ketohydroperoxide (KHP) in a modified cooperative fuel research engine (CFR) during combustion decreased with ethanol addition. However, the KHP rate of BHE15 (BHE15 refers to a blend of 15% ethanol and 85% biodiesel/n-heptane) and BHE20 (BHE20 refers to a blend of 20% ethanol and 80% biodiesel/n-heptane) is similar, causing the closed onset of low-temperature heat release. The rate of CH2O and MP2D of BH is the highest over the others in CID 510. The rate of CH2O and MP2D of BHE5 is lower than that of BHE10 (BHE10 refers to a blend of 10% ethanol and 90% biodiesel/n-heptane), BHE15, and BHE20.

The recent discovery of a class of sodalitelike clathrate superhydrides (e.g., ${\mathrm{YH}}_{6}$, ${\mathrm{YH}}_{9}$, ${\mathrm{ThH}}_{9}$, ${\mathrm{ThH}}_{10}$, and ${\mathrm{LaH}}_{10}$) at extreme pressures, which commonly exhibit high-temperature superconductivity with the highest ${T}_{c}$ approaching 260 K for ${\mathrm{LaH}}_{10}$, opened up a new era in the search for high-temperature superconductors in metal superhydrides. There is high interest in finding alternative clathrate superhydrides that might witness the long-dreamed room-temperature superconductivity. Here, we target the experimental synthesis of europium (Eu) superhydrides where theory can fail for the prediction of superconductivity. We pressurized and laser heated a mixture of metal Eu and ammonia borane $({\mathrm{NH}}_{3}{\mathrm{BH}}_{3})$ in a diamond-anvil cell and successfully synthesized the clathrate structured ${\mathrm{EuH}}_{6}$ and ${\mathrm{EuH}}_{9}$ at conditions of 152 GPa and 1700 K, and 170 GPa and 2800 K, respectively. Two nonclathrate structured phases of ${\mathrm{EuH}}_{5}$ and ${\mathrm{EuH}}_{6}$ were also synthesized that are not reported in lanthanide superhydrides. Theoretical simulations predicted that all the synthesized europium hydrides are magnetic, where the electrical resistance measurements suggest a possible magnetic order transition temperature at around 225 and 258 K, respectively, for ${\mathrm{EuH}}_{5}$ and clathrate ${\mathrm{EuH}}_{6}$. Our work has created a model superhydride platform for subsequent investigations on how a strongly correlated effect and magnetism can affect the superconductivity of superhydrides.

In the present study, we describe the development of betaxolol hydrochloride and montmorillonite with ion exchange in a single formulation to create a novel micro-interactive dual-functioning sustained-release delivery system (MIDFDS) for the treatment of glaucoma. Betaxolol hydrochloride molecule was loaded onto the montmorillonite by ion exchange and MIDFDS formation was confirmed by XPS data. MIDFDS showed similar physicochemical properties to those of Betoptic, such as particle size, pH, osmotic pressure, and rheological properties. Nevertheless, the microdialysis and intraocular pressure test revealed better in vivo performance of MIDFDS, such as pharmacokinetics and pharmacodynamics. With regards to wettability, MIDFDS had a larger contact angle (54.66 ± 5.35°) than Betoptic (36.68 ± 1.77°), enabling the MIDFDS (2.93 s) to spread slower on the cornea than Betoptic (2.50 s). Moderate spreading behavior and oppositely charged electrostatic micro-interactions had a comprehensive influence on micro-interactions with the tear film residue, resulting in a longer precorneal retention time. Furthermore, MIDFDS had a significant sustained-release effect, with complete release near the cornea. The dual-functioning sustained-release carrier together with prolonged pre-corneal retention time (80 min) provided sufficiently high drug concentrations in the aqueous humor to achieve a more stable and long-term IOP reduction for 10 h. In addition, cytotoxicity and hemolysis tests showed that MIDFDS had better biocompatibility than Betoptic. The dual-functioning microspheres presented in this study provide the possibility for improved compliance due to low cytotoxicity and hemolysis, which suggests promising clinical implications.

The investigations on gold science have been capturing research interest due to its diverse physical and chemical properties. Gold hydrides in the solid state, as a member of the Au compound family, are rare since the reaction of Au with H is hindered in terms of their similar electronegativity. It is expected that Li and F can provide electrons and holes, respectively, to help stabilize gold hydrides under high pressure. Herein, by means of a crystal structural search based on particle swarm optimization methodology accompanied by first-principles calculations, four hitherto unknown Li-Au-H compounds (i.e., LiAuH, LiAu2H, Li2Au2H, and Li6AuH) are predicted to be stable under compression. Intriguingly, Au-H bonding is found in LiAuH, LiAu2H, and Li2Au2H. As the gold content increases, Au atom arrangements exhibit diverse forms, from the chain in Li6AuH, the square layer in LiAuH, the network in Li2Au2H, and eventually to the coexistence of square and pyramid layers in LiAu2H. Additionally, Li6AuH has a unique cage-type lithium structure. Furthermore, electron-phonon coupling calculations show that these Li-Au-H phases are phonon-modulated superconductors with a superconducting critical temperature of 1.3, 0.06, and 0.02 K at 25 GPa and 2.79 K at 100 GPa. In contrast, we also identified two solid F4AuH and F6AuH phases with unexpected semiconductivity. They have structural configurations of H-bridged AuF4 quasi-square components and distorted AuF6 octahedrons, respectively, and have no gold-to-hydrogen bonds. Our current results indicate that electron doping at suitable concentrations under pressure can stabilize unique gold hydrides, and provide deep insights into the structures, electron properties, bonding behavior, and stability mechanism of ternary Li-Au-H and F-Au-H compounds.

Metal phosphides have triggered growing interest for their exotic structures and striking properties. Hence, within advanced structure search and first-principle calculations, we identify several unprecedented Y-P compounds (e.g., Y 3 P, Y 2 P, Y 3 P 2 , Y 2 P 3 , YP 2 , and YP 3 ) under compression. Interestingly, as phosphorus content increases, P atoms exhibit diverse behaviors corresponding to standalone anion, dumbbell, zigzag chain, planar sheet, crossing chain-like network, buckled layer, three-dimensional framework, and wrinkled layer. Particularly, Fd -3 m YP 2 can be viewed as assemblage of diamond-like Y structure and rare vertex-sharing tetrahedral P4 units. Impressively, electron-phonon coupling (EPC) calculations elucidate that Pm -3 m Y 3 P possesses the highest superconducting critical temperature T c of 10.2 K among binary transition metal phosphides. Remarkably, the EPC of Pm -3 m Y 3 P mainly arises from the contribution of low-frequency soft phonon modes, whereas mid-frequency phonon modes of Fd -3 m YP 2 dominate. These results strengthen knowledge of metal phosphides and pave a way for seeking superconductive transition metal phosphides.

Total petroleum hydrocarbons (TPH) is an important parameter for evaluating risk and establishing cleanup requirements at petroleum release sites. However, different analytical methods may provide incomparable results. To select more appropriate method and design cost-effective remediation strategy, a comparison study of four analytical methods (gravimetric method, infrared spectrometry (IR), gas chromatography-flame ionization detection (GC-FID), and ultraviolet spectrophotometer (UV)) is conducted for soil samples spiked by crude oil and fuel oils under both non-weathered and short-term weathered conditions. The gravimetric method produces higher TPH recovery for less volatile samples such as samples contaminated by motor oil and crude oil. The UV method reports very low TPH recovery and thus fails to provide the meaningful results in all tested samples. The IR method is a quick and relatively inexpensive screening tool and generally gives high TPH recovery, but the method precision and reproducibility are relatively low. The GC-FID method is relatively expensive and time consuming, but it has several advantages: (1) is more selective to hydrocarbons; (2) the method precision and reproducibility is relatively high; (3) is able to provide chemical fingerprint information. Therefore, appropriate method and should be chosen carefully depending on oil contamination type and investigation purpose. The results of short-term simulated weathering experiment showed 99.6% and 65.3% of TPH measured by the GC-FID method were removed for the kerosene and diesel contaminated soils after 14 days of weathering at 50oC, respectively. We have provided evidence that weathering is an important attenuation pathway at kerosene and diesel spill sites. We can design the most cost-effective remediation strategy according to different oil types spilled.

Experimental evidence has revealed superconductivity with a critical temperature, Tc, around 100 K in compressed solid phosphine, but theoretical studies have hitherto found no stable structure in any binary P-H system, leaving the characterization of the new superconductor unsettled. Here we present the findings of an advanced structure search and first-principles calculations unveiling the effect of Li as an electron donor that stabilizes the crystal structure and produces robust phonon-mediated superconductivity in the resulting Li-P-H compounds in wide ranges of stoichiometry and pressure. We showcase a trigonal LiP2H14 phase that reaches Tc of 169 K at 230 GPa and then decreases with rising pressure, which can be remedied by substituting Li with Be or Na, which considerably enhances Tc. These findings highlight the intricate and effective chemical tuning of stabilizing the crystal structure and enhancing the superconductivity in a distinct class of ternary hydrides, opening new avenues for designing and optimizing new high-Tc hydride superconductors.

Montmorillonite-loaded solid lipid nanoparticles with good biocompatibility, using Betaxolol hydrochloride as model drug, were prepared by the melt-emulsion sonication and low temperature-solidification methods and drug bioavailability was significantly improved in this paper for the first time to application to the eye. The appropriate physical characteristics were showed, such as the mean particle size, Zeta potential, osmotic pressure, pH values, entrapping efficiency (EE%) and drug content (DC%), all showed well suited for possible ocular application. In vitro release experiment indicated that this novel system could continuously release 57.83% drugs within 12 h owing to the dual drug controlled-release effect that was achieved by ion-exchange feature of montmorillonite and structure of solid lipid nanoparticles. Low irritability and good compatibility of nanoparticles were proved by both CAM-TBS test and cytotoxicity experiment. We first discovered from the results of Rose Bengal experiment that the hydrophilicity of the drug-loaded nanoparticles surface was increased during the loading and releasing of the hydrophilic drug, which could contribute to prolong the ocular surface retention time of drug in the biological interface membrane of tear-film/cornea. The results of in vivo pharmacokinetic and pharmacodynamics studies further confirmed that increased hydrophilicity of nanoparticles surface help to improve the bioavailability of the drug and reduce intraocular pressure during administration. The results suggested this novel drug delivery system could be potentially used as an in situ drug controlled-release system for ophthalmic delivery to enhance the bioavailability and efficacy.

Exploration of photovoltaic materials has received enormous interest for a wide range of both fundamental and applied research. Therefore, in this work, we identify a CsSi compound with a Zintl phase as a promising candidate for photovoltaic material by using a global structure prediction method. Electronic structure calculations indicate that this phase possesses a quasi-direct band gap of 1.45 eV, suggesting that its optical properties could be superior to those of diamond-Si for capturing sunlight from the visible to the ultraviolet range. In addition, a novel silicon allotrope is obtained by removing Cs atoms from this CsSi compound. The superconducting critical temperature (Tc) of this phase was estimated to be of 9 K in terms of a substantial density of states at the Fermi level. Our findings represent a new promising CsSi material for photovoltaic applications, as well as a potential precursor of a superconducting silicon allotrope.

A challenging but pressing task to design and synthesize novel, efficient, and robust pH‐universal hydrogen evolution reaction (HER) electrocatalysts for scalable and sustainable hydrogen production through electrochemical water splitting. Herein, we report a facile method to prepare an efficient and robust Ru‐M (M=Ni, Mn, Cu) bimetal nanoparticle and carbon quantum dot hybrid (RuM/CQDs) for pH‐universal HER. The RuNi/CQDs catalysts exhibit outstanding HER performance at all pH levels. The unexpected low overpotentials of 13, 58, and 18 mV shown by RuNi/CQDs allow a current density of 10 mA cm−2 in 1 m KOH, 0.5 m H2SO4, and 1 m PBS, respectively, for Ru loading at 5.93 μgRu cm−2. This performance is among the best catalytic activities reported for any platinum‐free electrocatalyst. Theoretical studies reveal that Ni doping results in a moderate weakening of the hydrogen bonding energy of nearby surface Ru atoms, which plays a critical role in improving the HER activity.

Determination of the structures of materials involving more light elements such as boron-rich compounds is challenging and technically important in understanding their varied compositions and super...

Recently fabricated two-dimensional (2D) black phosphorene (BP) is considered to be a promising optoelectronic sheet, but its applications are hindered by the poor stability in air. Thus, it is des...

Hydrogen-rich compounds attract significant fundamental and practical interest for their ability to accommodate diverse hydrogen bonding patterns and their promise as superior energy storage materials. Here, we report on an intriguing discovery of exotic hydrogen bonding in compressed ammonia hydrides and identify two novel ionic phases in an unusual stoichiometry NH7. The first is a hexagonal R3 m phase containing NH3-H+-NH3, H-, and H2 structural units stabilized above 25 GPa. The exotic NH3-H+-NH3 unit comprises two NH3 molecules bound to a proton donated from a H2 molecule. Above 60 GPa, the structure transforms to a tetragonal P41212 phase comprising NH4+, H-, and H2 units. At elevated temperatures, fascinating superionic phases of NH7 with part-solid and part-liquid structural forms are identified. The present findings advance fundamental knowledge about ammonia hydrides at high pressure with broad implications for studying planetary interiors and superior hydrogen storage materials.

The search for hard superconductive materials has attracted a great deal of attention due to their fundamentally interesting properties and potentially practical applications. Here we predict a new class of materials based on sodalite-like BN frameworks, X(BN)6, where X = Al, Si, Cl, etc. Our simulations reveal that these materials could achieve high superconducting critical temperatures ( Tc) and high hardness. Electron-phonon calculations indicate that Tc of these compounds varies with the doping element. For example, the superconducting Tc of sodalite-like Al(BN)6 is predicted to reach ∼47 K, which is higher than that in the renowned MgB2 (39 K). This phase and a series of other sodalite-based superconductors are predicted to be metastable phases but are dynamically stable as well. These doped sodalite-based structures are likely to become recoverable as potentially useful superconductors with high hardness. Our current results present a new strategy for searching for hard high- Tc materials.

The search of single nitrogen bond phases is of fundamental interest since they are potential high energy content materials. Recently, several experiments have reported the existence of a novel N H phase with single nitrogen bonds. However, there is no detailed information on the structures and the mechanism on its formation. In this work, formation of the N H phase was investigated employing first-principles molecular dynamics at high pressure and room temperature. The results reveal that N2 reacts readily with H2 molecules under moderate pressure at room temperature. The resulting compound is composed mainly of single N N bonds. The calculated vibrational density of state at 50 GPa is in good agreement with the experimental Raman spectrum. The theoretical results offer insights into the understanding of the polymeric mechanism in nitrogen compounds.

In recent decades, hydrogen-rich compounds are promising candidates for room-temperature superconductors under extremely high pressure. Remarkably, the theory-oriented finding of covalent hydride H3S and a class of clathrate hydrides, such as YH9 and LaH10, with high superconducting critical temperature (Tc) above 240 K, which give rise to the hope of searching for room-temperature superconductivity among hydrogen-rich compounds under high pressure. In this paper, we focus on the research progress of binary and ternary hydrides, provide the introduction of conventional phonon-mediated superconductivity theory and the physical mechanism of high-temperature superconductivity briefly, and offer an outlook on the challenge of discovering room-temperature superconductors among hydrogen-rich compounds in the future.

(R)-1-[3-(Trifluoromethyl)phenyl]ethanol ((R)-MTF-PEL) is an important chiral building block for the synthesis of a neuroprotective compound, (R)-3-(1-(3-(trifluoromethyl)phenyl)ethoxy)azetidine-1-carboxamide. In this work, an effective whole-cell-catalyzed biotransformation was developed to produce (R)-MTF-PEL, and its productivity was increased by medium engineering strategy. The recombinant E. coli BL21(DE3)-pET28a(+)-LXCAR-S154Y variant affording carbonyl reductase was adopted for the reduction of 3'-(trifluoromethyl)acetophenone to (R)-MTF-PEL with enantiomeric excess (ee) > 99.9%. The addition of 0.6% Tween-20 (w/v) boosted the bioreduction, because the substrate concentration was increased by 4.0-fold than that in the neat buffer solution. The biocatalytic efficiency was further enhanced by introducing choline chloride: lysine (ChCl:Lys, molar ratio of 1:1) in the reaction medium, because the product yield reached 91.5% under 200 mM substrate concentration in the established Tween-20/ChCl:Lys-containing system, which is the highest ever reported for (R)-MTF-PEL production. The optimal reduction conditions were as follows: 4% (w/v) ChCl:Lys, 12.6 g (DCW)/L recombinant E. coli cells, pH 7.0, 30 ℃ and 200 rpm, reaction for 18 h. The combined strategy of surfactant and NADES has great potential in the biocatalytic process and the synthesis of chiral alcohols.

Given the highly possible existence of nickel and silicon in the Earth's core, the study of the reaction between Ni and Si and the resulting structures at the pressure corresponding to that of the Earth's core is highly required. Therefore, we have investigated the crystal structures of Ni–Si compounds at pressures of 0–350 GPa by adopting a crystal structure search algorithm in conjunction with first-principles calculations. We uncover two high Ni-content Ni5Si and Ni6Si compounds with 12-coordination Si bonded with Ni, with both showing strong chemical stability in the Earth’s core. Bonding analysis reveals that the Ni atoms in these Ni–Si compounds present oxidant features and act as electron acceptors. This distinctive anomaly is the natural result of the energy shifts of the Ni 3d and Si 3p bands, resulting in charge transfer from Si to Ni. By examining the key properties (e.g., density and sound velocities) of the Ni5Si and Ni6Si compounds, the obtained density lies within the range of the Earth’s inner core, and the estimated sound velocities are found to be consistent with seismic data. These results indicate that these two compounds could be considered as possible core constituents. Our findings provide valuable insights into the enigmatic Earth's core as well as geophysical and geochemical processes.

Despite extensive experimental and theoretical work, consensus on the crystal structure and stability of the helium-hydrogen system is lacking. In this study, we investigate the possibility of helium forming a stable compound with hydrogen by using a first-principles structure search method. As a result of first-principles simulations, we predict a helium-hydrogen compound that is mechanically stable below 8 GPa with a $\mathrm{He}{({\mathrm{H}}_{2})}_{3}$ stoichiometry. Topological analysis of electron density at the bond critical points shows that there exists a quantifiable level of van der Waals interaction between helium and hydrogen in this $\mathrm{He}{({\mathrm{H}}_{2})}_{3}$ crystal. Our current results provide a case of weak interaction in a mixed hydrogen-helium system, offering insights for the evolution of interiors of giant planets such as Jupiter and Saturn.

Summary Mitochondrial pH is a vital parameter of the mitochondrial environment, which determines the rate of many mitochondrial functions, including metabolism, membrane potential, fate, etc. Abnormal mitochondrial pH is always closely related to the health status of cells. Analyzing mitochondrial pH can serve as a proxy for mitochondrial and cellular function. This protocol describes the use of SNARF-1 AM, a pH-sensitive fluorophore, to measure mitochondrial pH. This protocol details the steps to evaluate mitochondrial pH in live adult cardiomyocytes using confocal microscopy. The protocol can be adapted to other adherent cell types. For complete details on the use and execution of this protocol, please refer to Wei-LaPierre et al. (2013)., Graphical abstract, Highlights • SNARF-1 AM is a pH-sensitive fluorophore for measuring mitochondrial pH • Mitochondrial pH measurements in live cells with confocal microscopy • This protocol uses live cardiomyocytes but can be easily adapted to other adherent cells, Mitochondrial pH is a vital parameter of the mitochondrial environment, which determines the rate of many mitochondrial functions, including metabolism, membrane potential, fate, etc. Abnormal mitochondrial pH is always closely related to the health status of cells. Analyzing mitochondrial pH can serve as a proxy for mitochondrial and cellular function. This protocol describes the use of SNARF-1 AM, a pH-sensitive fluorophore, to measure mitochondrial pH. This protocol details the steps to evaluate mitochondrial pH in live adult cardiomyocytes using confocal microscopy. The protocol can be adapted to other adherent cell types.

Mitochondria are highly dynamic organelles, constantly undergoing shape changes, which are controlled by mitochondrial movement, fusion, and fission. Mitochondria play a pivotal role in various cellular processes under physiological and pathological conditions, including metabolism, superoxide generation, calcium homeostasis, and apoptosis. Abnormal mitochondrial morphology and mitochondrial protein expression are always closely related to the health status of cells. Analysis of mitochondrial morphology and mitochondrial protein expression in situ is widely used to reflect the abnormality of cell function in the chemical fixed sample. Paraformaldehyde (PFA), the most commonly used fixative in cellular immunostaining, still has disadvantages, including loss of antigenicity and disruption of morphology during fixation. We tested the effect of ethanol (ETHO), PFA, and glutaraldehyde (GA) fixation on cellular mitochondria. The results showed that 3% PFA and 1.5% GA (PFA-GA) combination reserved mitochondrial morphology better than them alone in situ in cells. Mitochondrial network and protein antigenicity were well maintained, indicated by preserved MitoTracker and mitochondrial immunostaining after PFA-GA fixation. Our results suggest that the PFA-GA combination is a valuable fixative for the study of mitochondria in situ.

The study of superconductivity in compressed hydrides is of great interest due to measurements of high critical temperatures (Tc) in the vicinity of room temperature, beginning with the observations of LaH10 at 170–190 GPa. However, the pressures required for synthesis of these high-Tc superconducting hydrides currently remain extremely high. Here we show the investigation of crystal structures and superconductivity in the La-B-H system under pressure with particle-swarm intelligence structure-searches methods in combination with first-principles calculations. Structures with seven stoichiometries, LaBH, LaBH4, LaBH6, LaBH7, LaBH8, La(BH)3, and La(BH4)3 were predicted to become stable under pressure. Remarkably, the hydrogen atoms in LaBH8 were found to bond with B atoms in a manner that is similar to that in H3S. Lattice dynamics calculations indicate that LaBH7 and LaBH8 become dynamically stable at pressures as low as 109 and 48 GPa, respectively. Moreover, the two phases were predicted to be superconducting with a critical temperature Tc of 93 K and 156 K at 110 GPa and 55 GPa, respectively (μ∗ = 0.1). The present results provide guidance for future experiments targeting hydride superconductors with both low synthesis pressures and high Tc., The work was supported by National Natural Science Foundation of China (No. 52022089, No. 11874076, No. 52090024, and No. 12074138), and the Ph.D. Foundation by Yanshan University (Grant No. B970). A.B. acknowledges financial support from the Spanish Ministry of Science and Innovation (Grant No. FIS2019-105488GB-I00). R.J.H. acknowledges support from the U.S. National Science Foundation (Grant No. DMR-1933622).

Tailoring the inherent structure of materials is an effective way to improve the hydrogen storage capacity of metal materials. In this work, we report the effect of rhodium (Rh) nanocrystals (NCs) on the hydrogenation reaction. We found that Rh NCs could form rhodium monohydride (RhH) at a lower pressure than the bulk Rh because of its high specific surface area and structure defects. In addition, Rh NCs in the form of icosahedrons exhibited a much higher hydrogen absorption efficiency than Rh nanocubes. Furthermore, much smaller irregular Rh nanoparticles are even partially converted to RhH at lower pressure because of the nanosize effect. We thus believe that it is possible to design materials with excellent hydrogen storage properties under mild conditions.

The study of titanium trisulfide (TiS3) has been an intensely researched subject due to the wide range of industrial applications (e.g., photo-voltaic and thermoelectric devices). The effects of pressure in reducing inter-atomic distances and modifying crystal structures are well known, thus pressure may provide a route to improve the physical or chemical properties of materials. We herein report the prediction of potential superconductivity in titanium trisulfide by first principles calculations in combination with a swarm structure search methodology. We found that pressure can efficiently alter the crystal structures in TiS3 from the monoclinic phase into a cubic phase at 71 GPa accompanied by the destruction of layered packing pattern with S-S units and forming infinitely S-S linear chains in three dimensions. Strikingly, our study unravels the superconductive potential of this cubic phase with an estimated transition temperature of ∼9.3 K at 80 GPa. Our current results offer insights into understanding the high-pressure electronic behaviors of solid TiS3.

We present a comprehensive study on structural and electronic properties of lanthanum intermetallic compounds (${M}_{x}{\mathrm{La}}_{y}$, $M=\text{Be}$, Mg, Al, Ga, In, Tl, Pb, and Bi) under high pressure. By using a swarm intelligence structure search method combined with first-principles calculations, pressure-induced phase transitions of ${M}_{x}{\mathrm{La}}_{y}$ were investigated, with several new structures predicted. A universal yet intriguing phenomenon was found; that is, all of these compounds will decompose into elemental solids at certain pressures, which is against the general intuition that extreme pressure always stabilizes and densifies materials. Mechanical analysis suggests that this anomalous behavior is associated to the elastic moduli and interatomic interaction in ${M}_{x}{\mathrm{La}}_{y}$, and their changes under extreme pressure. A low bulk modulus and larger atomic volume of La result in a smaller volume for the elemental mixture compared to their compound at high pressures, which leads to an energetically favorable $PV$ work and enthalpy for the elemental mixture. Furthermore, the external pressure tends to weaken the La-$M$ electrostatic interaction in compounds as evidenced by the reduced charge transfer between La and $M$, which in turn modifies the electronegativity of La and $M$ and destabilizes the compounds. Our results shed light on the high-pressure behaviors of La-based intermetallic compounds and provide important guidance for understanding other La-like intermetallic compounds at high pressures.

The study of two-dimensional (2D) materials has attracted considerable attention owing to their unique but fascinating properties. Here we systematically explored 2D carbon nitride monolayer sheets via the particle swarm optimization algorithm in combination with density functional theory. As a result of structural searches, four carbon nitride monolayers are predicted with stable stoichiometries of C5N2, C2N, C3N2 and CN. These predicted structures are semiconductors with an optimal band gap for solar cell application as indicated in our electronic simulations. Our current results also reveal the high tensile strengths of the predicted structures compared to known porous carbon nitride monolayer sheets. This work may provide a route for the design of 2D candidates in the application of photovoltaic materials.

A hybrid photocatalyst with high photocatalytic activity under visible light was developed. The photocatalyst – graphene oxide (GO)/hemin/titanium dioxide (TiO2) nanocomposite was prepared by a simple method via adsorption at room temperature within 3 h, and was characterised using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV–Vis spectroscopy. The results show that TiO2 nanoparticles were dispersed on the surface of GO sheets uniformly, and the crystal structure remained the same as original anatase TiO2 phase in the presence of GO and hemin. Extended absorption of the nanocomposite into the visible region is benefit for the novel hybrid photocatalyst to utilise visible light more efficiently in the photocatalytic reaction. The photocatalytic activity increased about 70% in the presence of GO and hemin (96%) comparing to pure TiO2 (26%). The nanocomposite catalyst could stably adsorb and degrade methylene blue of different concentration without H2O2 or sacrificial electron donor at a relatively wide range of pH values within 3 h. As well as, the prepared GO/hemin/TiO2 nanocomposite shows good stability and reusability in the photocatalytic reaction, enabling it a potential application in wastewater treatment.

Pressure is a useful tool to profoundly modify the volume and electronic structure of materials, resulting in the formation of new structures with exotic physical and chemical properties. The high-symmetry cubic barium fluoride (BaF2) with a space group of Fm-3m (Z = 4) is the prototypical fluorite-type compounds at ambient condition, which is shared with many alkaline-earth fluorides. The study of high-pressure evolution of the BaF2 phase is of fundamental importance in helping to understand the structural sequence and principles of crystallography. In this work, we here have systematically investigated the high-pressure structural transition of BaF2 up to 200 GPa using an effective CALYPSO methodology. Strikingly, two thermodynamically favored phases with orthorhombic Pnma and hexagonal P63/mmc symmetry are found at 3.6 and 19.2 GPa, respectively. Distinguishingly, P63/mmc phase remains stable up to 90.5 GPa, and then transform to Pnma structure. Further electronic calculations indicate that BaF2 maintains insulating feature until 200 GPa. Our current results have broad implications for other AB2-type compounds that may harbor similar novel structured evolution behavior at high pressure.

To explore the effect of the addition of ethanol (E) on the combustion behavior of biodiesel/n-heptane (BH) blends, autoignition characteristics of the BHE blends were studied in two experimental systems: a modified cooperative fuel research (CFR) engine and a constant-volume combustion chamber (CID 510) used for rating the derived cetane number of fuels. The observations of ignition behavior include the critical compression ratio and heat release profile, which are assessed using the CFR engine. The equivalence ratio is 0.25 and 0.45, respectively, while the physical and chemical ignition delays are measured by the CID 510 under a wide range of air temperatures and oxygen dilution levels. With the addition of the ethanol, the critical compression ratio increases, which indicates that the reactivity decreases. According to the heat profiles, because of the complex composition of the blend, the onset of the high temperature heat release (HTHR) and low temperature heat release (LTHR) did not vary linearly w...

Single crystals of a complex Zintl compound with the composition Na_4Ge_(13) were synthesized for the first time using a high-pressure/high-temperature approach. Single-crystal diffraction of synchrotron radiation revealed a hexagonal crystal structure with P6/m space group symmetry that is composed of a three-dimensional sp^3 Ge framework punctuated by small and large channels along the crystallographic c axis. Na atoms are inside hexagonal prism-based Ge cages along the small channels, while the larger channels are occupied by layers of disordered sixfold Na rings, which are in turn filled by disordered [Ge_4]^(4–) tetrahedra. This compound is the same as “Na_(1–x)Ge_(3+z)” reported previously, but the availability of single crystals allowed for more complete structural determination with a formula unit best described as Na_4Ge_(12)(Ge_4)_(0.25). The compound is the first known example of a guest–host structure where discrete Zintl polyanions are confined inside the channels of a three-dimensional covalent framework. These features give rise to temperature-dependent disorder, as confirmed by first-principles calculations and physical properties measurements. The availability of single-crystal specimens allowed for measurement of the intrinsic low-temperature transport properties of this material and revealed its semiconductor behavior, which was corroborated by theoretical calculations.

Crystal structure prediction techniques coupled with enthalpies obtained at 0 K from density functional theory calculations suggest that pressure can be used to stabilize the chlorides of xenon. In particular, XeCl and XeCl2 were calculated to become metastable by 10 GPa and thermodynamically stable with respect to the elemental phases by 60 GPa. Whereas at low pressures Cl2 dimers were found in the stable phases, zigzag Cl chains were present in Cmcm XeCl at 60 GPa and atomistic chlorine comprised P63/mmc XeCl and Fd3m XeCl2 at 100 GPa. A XeCl4 phase that was metastable at 100 GPa contained monomers, dimers, and trimers of chlorine. XeCl, XeCl2, and XeCl4 were metallic at 100 GPa, and at this pressure they were predicted to be superconducting below 9.0, 4.3, and 0.3 K, respectively. Spectroscopic properties of the predicted phases are presented to aid in their eventual characterization, should they ever be synthesized.

Tungsten nitrides have been intensely studied for technological applications owing to their unique mechanical, chemical, and thermal properties. Combining first-principles calculations with an unbiased structural searching method (CALYPSO), we uncovered a novel orthorhombic structure with a space group Cmc21 as the thermodynamically most stable phase for tungsten dinitride (WN2) between 46–113 GPa. The computed elastic constants and phonons reveal that the Cmc21-WN2 structure is dynamically stable at atmospheric pressure. Moreover, hardness calculations indicate that this structure is likely to become a hard material. Our current results may stimulate further experimental work on synthesizing these technologically important materials and improve the understanding of the pressure-induced phase transitions of other transition-metal light-element compounds.

Using earth abundant transition metal-based compounds to replace noble metal catalysts towards hydrogen evolution from water splitting seems to have great importance worldwide. Compositional modulation and structural design on nanoscale have been hot topics for the optimization of their catalytic properties and have attracted great research interest. In this study, we report Co/CoN Janus nanoparticles embedded in a porous nitrogen doped carbon (Co/CoN–NC) composite catalyst, derived by the heat treatment of a Co2+ containing polymer in ammonia atmosphere. The as-obtained hybrid catalyst showed excellent electrocatalytic activities for the hydrogen evolution reaction in both acidic and basic media, and it delivered a current density of 10 mA cm−2 at the overpotential of 160 mV in 1 M KOH and 190 mV in 0.5 M H2SO4 electrolyte. In addition, the catalyst could sustain potentiostatic electrolysis for at least 100 hours at 10 mA cm−2 in both acidic and alkaline solutions. Mechanistic study suggested that the high activity of the composite electrocatalyst originated from the Janus effects between Co and CoN, which enhanced the electron transfer efficiency and led to fast hydrogen adsorption and desorption kinetics.

Recent theoretical calculations predict that megabar pressure stabilizes very hydrogen-rich simple compounds having new clathrate-like structures and remarkable electronic properties including room-temperature superconductivity. X-ray diffraction and optical studies demonstrate that superhydrides of lanthanum can be synthesized with La atoms in an fcc lattice at 170 GPa upon heating to about 1000 K. The results match the predicted cubic metallic phase of LaH10 having cages of thirty-two hydrogen atoms surrounding each La atom. Upon decompression, the fcc-based structure undergoes a rhombohedral distortion of the La sublattice. The superhydride phases consist of an atomic hydrogen sublattice with H-H distances of about 1.1 A, which are close to predictions for solid atomic metallic hydrogen at these pressures. With stability below 200 GPa, the superhydride is thus the closest analogue to solid atomic metallic hydrogen yet to be synthesized and characterized.

In the present work, a novel metal-free ORR electrocatalyst, with large specific surface area (2600 m 2 g −1 ), high content of N dopants (3.12 at.%) and 3D cross-linking hierarchically porous structure (abbreviated as LHNHPC) is readily prepared by using a modified classical carbon-aerogel method with NH 3 as the activating agent. Compared with benchmark Pt/C catalyst, it is found that, LHNHPC exhibits similar electrocatalytic activity towards oxygen reduction reaction (ORR), superior durability and excellent methanol tolerance in basic media. The above electrochemical properties of LHNHPC are mainly attributed to the synergistic contribution of its unique hierarchical pore structure, the rich N doping and the large surface area. It can be anticipated that the proposed two-step process could be used for mass production of metal free electrocatalysts for a wide range of electrochemical devices including fuel cells and metal-air batteries.

A systematic structure search in the La–H and Y–H systems under pressure reveals some hydrogen-rich structures with intriguing electronic properties. For example, LaH10 is found to adopt a sodalite-like face-centered cubic (fcc) structure, stable above 200 GPa, and LaH8 a C2/m space group structure. Phonon calculations indicate both are dynamically stable; electron phonon calculations coupled to Bardeen–Cooper–Schrieffer (BCS) arguments indicate they might be high-Tc superconductors. In particular, the superconducting transition temperature Tc calculated for LaH10 is 274–286 K at 210 GPa. Similar calculations for the Y–H system predict stability of the sodalite-like fcc YH10 and a Tc above room temperature, reaching 305–326 K at 250 GPa. The study suggests that dense hydrides consisting of these and related hydrogen polyhedral networks may represent new classes of potential very high-temperature superconductors.

Using global structure searches, we have explored the structural stability of CaB$_3$N$_3$, a compound analogous to CaC$_6$, under pressure. There are two high-pressure phases with space groups $\textit{R3c}$ and $\textit{Amm2}$ that were found to be stable between 29 and 42 GPa, and above 42 GPa, respectively. The two phases show different structural frameworks, analogous to graphitic CaC$_6$. Phonon calculations confirm that both structures are also dynamically stable at high pressures. The electronic structure calculations show that the $\textit{R3c}$ phase is a semiconductor with a band gap of 2.21 eV and that the $\textit{Amm2}$ phase is a semimetal. These findings help advance our understanding of the Ca-B-N ternary system.

High performance composite of nanosized Li4Ti5O12 (LTO) and graphene nanosheets was fabricated using a novel atomic layer deposition (ALD) seeded process incorporated with hydrothermal lithiation for the first time. TiO2 nanoislands as seeds were anchored on graphene by ALD process, triggering the unique structure formation of subsequent LTO. The synergistic effects of nanosized LTO and graphene endow the composite with a short lithium ion diffusion path and efficiently conductive network for electron and ion transport, boosting the excellent reversible capacity, rate capability, and cyclic stability as anode materials for lithium ion capacitors (LICs). The reversible capacity of 120.8 mA h g−1 at an extremely high current rate of 100 C was achieved successfully, and the electrode can be charged/discharged to about 70% of the theoretical capacity of LTO in 25 s. Meanwhile, the composite exhibited excellent cyclic stability of 90% capacity retention at 20 C with nearly 100% Coulombic efficiency after 2500 cycles. The sintering treatment after hydrothermal reaction has significant effects on the crystallinity, defect density, microstructure and electrochemical property of the composite, which is also supported by theoretical calculations. The results provide a versatile roadmap for synthesis of high performance LTO based composite and new insights into LICs.

Carbon-based frameworks composed of sp3 bonding represent a class of extremely lightweight strong materials, but only diamond and a handful of other compounds exist despite numerous predictions. Thus, there remains a large gap between the number of plausible structures predicted and those synthesized. We used a chemical design principle based on boron substitution to predict and synthesize a three-dimensional carbon-boron framework in a host/guest clathrate structure. The clathrate, with composition 2Sr@B6C6, exhibits the cubic bipartite sodalite structure (type VII clathrate) composed of sp3-bonded truncated octahedral C12B12 host cages that trap Sr2+ guest cations. The clathrate not only maintains the robust nature of diamond-like sp3 bonding but also offers potential for a broad range of compounds with tunable properties through substitution of guest atoms within the cages.

The recent theory-orientated discovery of record high-temperature superconductivity (T_{c}∼250 K) in sodalitelike clathrate LaH_{10} is an important advance toward room-temperature superconductors. Here, we identify an alternative clathrate structure in ternary Li_{2}MgH_{16} with a remarkably high estimated T_{c} of ∼473 K at 250 GPa, which may allow us to obtain room-temperature or even higher-temperature superconductivity. The ternary compound mimics a Li- or electron-doped binary hydride of MgH_{16}. The parent hydride contains H_{2} molecules and is not a good superconductor. The extra electrons introduced break up the H_{2} molecules, increasing the amount of atomic hydrogen compared with the parent hydride, which is necessary for stabilizing the clathrate structure or other high-T_{c} structures. Our results provide a viable strategy for tuning the superconductivity of hydrogen-rich hydrides by donating electrons to hydrides via metal doping. Our approach may pave the way for finding high-T_{c} superconductors in a variety of ternary or quaternary hydrides.

Structure searches of beryllium chalcogenides (BeS, BeSe, and BeTe) at high pressures using a swarm intelligence algorithm, in conjunction with density functional theory, reveal modulated polymorphs, unusual for such simple binary compounds. Apart from the well-known cubic (space group $F\overline{4}3m$, zinc-blende structure) to hexagonal closed-packed (space group $P{6}_{3}/mmc$, nickel-arsenide structure) structural transition, a further transition at higher pressure to an orthorhombic structure is predicted for BeS and BeSe. The orthorhombic phase is space group Cmca in BeS and Pnma before finally adopting Cmca in BeSe, each accompanied by the onset of modulation of the atomic arrangement. The amplitude of displacements associated with the modulation increases with increasing pressure and molecular dynamics simulations show the modulated structure to become stable at least to 300 GPa and 2000 K. This unusual structural modulation is not seen, however, in BeTe, which instead transforms to a $C2/m$ phase. Links are drawn between the modulated phases of BeS and BeSe and the high-pressure modulated phases of their parent chalcogens. Our results provide key insights into understanding the modulation in binary compounds at high pressure.

Although many metal hydrides were predicted by theory, very few of those were so far realized in experiment. Here, we systematically investigated the Ta-H system below 85 GPa, and found that the hexagonal close-packed $\mathrm{Ta}{\mathrm{H}}_{\ensuremath{\sim}2}$ can be gradually transformed into $\mathrm{Ta}{\mathrm{H}}_{\ensuremath{\sim}3}$ above 60 GPa at room temperature. With the help of density-functional theory calculations, the space group of $\mathrm{Ta}{\mathrm{H}}_{\ensuremath{\sim}3}$ can be determined as a $I\overline{4}3d$ phase, which is isostructural to the Domeykite mineral. Such structure is rather rare and was not predicted in the earlier theoretical works due to the large unit cell. We also tried laser heating at high pressures and found that temperature plays a key role in tuning the $\mathrm{Ta}{\mathrm{H}}_{\ensuremath{\sim}3}$ phase to $\mathrm{Ta}{\mathrm{H}}_{\ensuremath{\sim}2}$ phase; however, no other new tantalum hydrides were synthesized. During decompression, the $\mathrm{Ta}{\mathrm{H}}_{\ensuremath{\sim}3}$ was completely decomposed to the $\mathrm{Ta}{\mathrm{H}}_{\ensuremath{\sim}2}$ below 30 GPa. Further experiments are still required for the synthesis of other tantalum polyhydrides at a higher pressure range and for the comparison with the theoretical calculations.

Silicon disulfide, ${\mathrm{SiS}}_{2}$, is thought to occur in interstellar dust and is of fundamental interest more generally among the silicon chalcogenides as a comparator to ${\mathrm{SiO}}_{2}$, an important component of terrestrial planets. However, the high-pressure behaviors of silicon sulfides are unclear. Here, using an efficient structure search method, we systematically explore the structural evolution of different Si-S stoichiometries up to 250 GPa. ${\mathrm{SiS}}_{2}$ is found to be stable below 155 GPa, above which it decomposes into two compounds, SiS and ${\mathrm{SiS}}_{3}$. SiS adopts a high-symmetry cubic structure consisting of eightfold-coordinated silicon in face-sharing ${\mathrm{SiS}}_{8}$ polyhedra, while ${\mathrm{SiS}}_{3}$ crystallizes in a rhombohedral structure containing ninefold-coordinated ${\mathrm{SiS}}_{9}$ polyhedra. Analyses suggest that the Si eightfold-coordination environment could be a common feature for group IV--VI compounds under high pressure. Our findings provide insights on the nature of Si-S compounds under ultrahigh pressure.

Transparent and flexible supercapacitors (TFSCs) could diversify the future wearable electronics owing to the fascinating optoelectronic and electrochemical performances. Herein, we report symmetric TFSCs assembled by reduced graphene oxide (rGO)@Ag nanowire/poly (ethylene terephthalate) (PET) transparent electrodes for capacitive storage, in which the interfacial structure of rGO film can be tuned by a facile freeze drying technique. The enlarged interlayer spacing of rGO film deteriorated the electronic migration derived from the loose layer structure, whereas about 33–52% of the areal capacitance of TFSCs was boosted as compared with the ones without freeze drying at the same transmittance. It is concluded that the enlarged inter-distance of rGO film could facilitate diffusion and transport of ions in the electrolyte, furthermore, the expanded rGO film could provide more interface to accommodate more ions for storage. The simulation results also confirmed the lower diffusion barrier and larger band gap of rGO with larger interlayer distance. The mechanically robust TFSCs exhibit the maximum energy density of 89.2 nWh cm−2, and the maximum power density of 4.63 μW cm−2 with remaining energy density of 41.1 nWh cm−2, as well as 3000 cyclic stability, demonstrating an efficient strategy toward high performance TFSCs.

Efficiency of whole-cell biocatalysis in aqueous buffer solution is mainly limited by the low cellular membrane permeability and poor solubility of hydrophobic non-natural substrate. In this study, highly efficient bioreduction of 3,5-bis(trifluoromethyl)acetophenone (BTAP) to (S)-1-[3,5-bis(trifluoromethyl)phenyl]ethanol ((S)-BTPE) with excellent enantioselectivity (> 99.9 % ee) by a novel yeast isolate Cyberlindnera saturnus ZJPH1807 was achieved via a integrated strategy of natural deep-eutectic solvent (NADES) and surfactant. The introduction of L-carnitine: lysine (C:Lys, molar ratio 1:2) in the reaction medium improved cell membrane permeability effectively and relieved BTAP toxicity to the cells. The Tween-80 addition further accelerated catalytic yield by increasing solubility of BTAP for 7.6-fold compared with neat aqueous buffer solution. After the optimization of key reaction parameters, a 81.0 % yield within 24 h under 500 mM substrate loading was achieved in the established C:Lys/Tween-80-containing system, compared with a 76.4 % yield for 30 h in aqueous buffer system under 200 mM BTAP concentration. This biocatalytic process was also feasible at 500 mL preparation scale with a 79.7 % (S)-BTPE yield under 500 mM BTAP. The developed combinational strategy of NADES with surfactant is an effective approach for enhancing bioreductive efficiency of hydrophobic substrates mediated by whole-cell catalyst, and has great potential in biocatalysis.