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We proved that ice crystallized from water molecules within as-synthesized graphene oxide (GO) can be used as a spacer among individual GO sheets to form an expanded GO aerogel with a three-dimensional porous network structure. This designed specific structure can be retained during further processes to form graphene paper. Due to the fact that the as-fabricated graphene paper contains carbon defects and space in its infrastructure, this creates more electroactive surfaces and interfaces to significantly increase the Faradaic reaction efficiency. With the introduction of redox-electrolyte K3Fe(CN)6 into a KOH electrolyte, we can obtain a 95-fold increase in the specific capacitance compared with the value obtained in the traditional KOH electrolyte. The ice-crystallization formed graphene paper electrode showed high electroactivity because the specific porous structure can favor the fast transfer of electrolyte ions, such as Fe(CN)63- ions. The presented results prove that ice-crystallization formed GO can serve as a chemically tunable platform for electrochemical energy storage applications. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal CrystEngComm, which focuses on the design and understanding of solid-state and crystalline materials. It includes a variety of papers on topics such as cocrystals, crystal structures, stimuli-responsive properties, and piezoelectric properties. The journal is published by The Royal Society of Chemistry, a leading chemistry community. The document also mentions approved training courses offered by the society. [Extracted from the article]

The document is a contents list for the journal CrystEngComm, which focuses on the design and understanding of solid-state and crystalline materials. It includes a range of papers on topics such as solid-state reactions, separation and crystallization of polymorphs, selective adsorption, and photoelectrochemical water oxidation. The journal is published by The Royal Society of Chemistry, a leading chemistry community that reinvests its profits back into the chemistry community. The document also mentions professional recognition and qualifications for scientists, as well as a correction to a previous article. [Extracted from the article]

As an important class of natural resources, lignin and its utilization receive more and more attention. However, it is treated as waste in paper industry and causes serious pollution of natural water bodies. Meanwhile, the uncontrollable surface topography and the crystal form of natural calcium carbonate (CaCO3) severely restrict its application in the industrial field. Biomineralization may provide a perfect solution for these two issues. In this work, two types of specific crystal forms, cinnamic acid & aragonite crystal (CAAs) and cinnamic acid & vaterite crystal (CAVs) were directly synthesized in the presence of cinnamic acid. Two kinds of polymorph states were also found in the growth process of CaCO3. The structural properties of CAAs and CAVs as well as their polymorph states were characterized by FESEM, AFM, FTIR spectroscopy, XRD and TGA. The results showed that CAAs and CAVs held the crystal forms of aragonite and vaterite, respectively. The crystal forms of CaCO3 followed the growth rule that they dynamically changed from calcite to aragonite and then to vaterite. The formation mechanism is illustrated in the nucleation and crystal growth processes of CaCO3; cinnamic acid first formed various surfaces with the change in ambient conditions. These made CaCO3 to form different crystal forms and surface structures. [ABSTRACT FROM AUTHOR]

As a highly biocompatible material, hydroxyapatite (HAP) has been used extensively in various fields. Ultralong HAP nanowires with ultrahigh aspect ratios possess prominent merits such as good flexibility, high biocompatibility, excellent mechanical properties, high thermal stability, and excellent fire resistance. Consequently, ultralong HAP nanowires are promising for applications in various fields. However, the large-scale, low-cost and environmentally friendly synthesis of ultralong HAP nanowires remains a great challenge. In this work, we have developed a scalable, low-cost and green method for the synthesis of ultralong HAP nanowires using peanut oil as one of the main reaction reagents. The effects of experimental parameters on the morphology of ultralong HAP nanowires are studied, including the amounts of peanut oil, sodium hydroxide and methanol, and the molar ratio of Ca/P. The synthetic formulation for preparing ultralong HAP nanowires has been optimized by varying the experimental conditions. Importantly, compared with a previously reported calcium oleate precursor solvothermal method using oleic acid, the synthetic method using peanut oil reported herein can significantly reduce the production cost for the synthesis of ultralong HAP nanowires. It is encouraging that peanut oil is an eco-friendly, inexpensive, and sustainable food; thus, the production cost for ultralong HAP nanowires can be significantly reduced. Moreover, the synthetic strategy reported herein can be scaled up for large-scale, green and low-cost production of ultralong HAP nanowires. This novel synthetic method is promising for future industry-scale production of ultralong HAP nanowires. Furthermore, based on ultralong HAP nanowires, fire-resistant inorganic paper has been prepared by a simple vacuum-assisted filtration method. The ultralong HAP nanowire-based fire-resistant inorganic paper exhibits advantages such as high flexibility, high whiteness without bleaching, nonflammability, and excellent high-temperature resistance, which are promising for applications in various fields. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal CrystEngComm. It provides information about the articles and papers included in the issue, as well as the authors and their research topics. The journal focuses on the design and understanding of solid-state and crystalline materials. The document also mentions the Royal Society of Chemistry, which is a leading chemistry community that connects the world with the chemical sciences. [Extracted from the article]

The document is a contents list for the journal CrystEngComm, which focuses on the design and understanding of solid-state and crystalline materials. It is published by the Royal Society of Chemistry, a leading chemistry community. The contents list includes various papers and communications on topics such as crystal forms of bilirubin, distribution of basal plane dislocations in SiC single crystals, and synthesis of charge transfer cocrystals. The document also mentions approved training courses offered by the Royal Society of Chemistry. [Extracted from the article]

The document is a contents list for the journal CrystEngComm, which focuses on the design and understanding of solid-state and crystalline materials. The list includes various papers on topics such as hybrid materials, growth of single-crystalline particles, high-pressure phase transitions, coordination polymers, and optical properties of crystals. The journal is published by The Royal Society of Chemistry, a leading chemistry community. The document also mentions professional recognition and development opportunities for scientists. [Extracted from the article]

The document is a contents list for the journal CrystEngComm. It highlights various articles and papers published in the journal, covering topics such as the self-assembly of short peptides, the bending and photosalient effect of flexible crystals, and the synthesis of energetic salts. The journal focuses on the design and understanding of solid-state and crystalline materials. The Royal Society of Chemistry, a leading chemistry community, publishes the journal and reinvests its profits back into the chemistry community. [Extracted from the article]

The document is a contents list for the journal CrystEngComm, which focuses on the design and understanding of solid-state and crystalline materials. The contents list includes various papers on topics such as acoustic shockwave-induced morphological transformation, copper-organic frameworks, and the assembly of poly(3-hydroxybutyrate). The journal is published by The Royal Society of Chemistry, a leading chemistry community. The document also mentions other journals in the field of environmental science. [Extracted from the article]

A general and programmed fast crystallization process (about 12 seconds) was designed to synthesize binary (MOx) and ternary (ABO3, A2BO4) metal oxide nanomaterials with controllable sizes and composition. The fast crystallization process mainly included the burning of metal-nitrate–filter-paper without additional energy supply and it can lead to the formation of exceptionally fine binary and ternary crystallites with sizes of ∼10–20 nm. The thermodynamic reduction potential of the metal-nitrate–filter-paper burning system can be estimated to be between −0.26 and 1.72 V, which can favor the occurrence of redox reactions, i.e. Cu2+→ Cu+→ Cu, Ni2+→ Ni, Co2+→ Co3+, Ce3+→ Ce4+, and Pr3+→ Pr4+. When used as anode materials for lithium-ion batteries, most of the as-burned metal oxides displayed high cycling stability. The discharge capacity of CoO nanoparticles can reach as high as 501.1 mA h g−1 after continuous 50 discharge–charge cycles at a current density of 100 mA g−1. The proposed fast crystallization route provided a versatile, facile and fast method for the synthesis of functional metal oxide nanomaterials with controllable sizes and composition. [ABSTRACT FROM AUTHOR]

A novel fluorescent material that can change its emission properties in response to different external stimuli holds significant importance for the development of sensors, information storage, and encryption materials. In this work, we designed and synthesized two zinc(II) coordination compounds, [Zn(HL)I2]·CH3OH (1) and [Zn(HL)Br2]·CH3OH (2), which exhibit remarkable changes in their emission properties under three different external stimuli. The two compounds were prepared using a simple one-pot method by reacting zinc(II) salts with 4-(N,N-diphenylamino)benzaldehyde and 3-amino-2-pyridinone. Under the stimulation of NH3 vapor, both compounds underwent decomposition, leading to a transformation of their fluorescence from yellow to blue, exhibiting a significant blue-shift of more than 170 nm. After exposure to HCl vapor, the fluorescence color of the two original compounds changed from yellow to red, and the color change could be easily distinguished by the naked eye under UV light irradiation. Then after fumigation with NH3 vapor, the color of both samples changed from red to blue. Based on the high-contrast NH3-responsive properties and HCl-responsive properties, we designed and developed test papers capable of detecting HCl vapor and NH3 vapor. Furthermore, due to the transformation from the crystalline state to the amorphous state during grinding, the two compounds also demonstrated high-contrast mechanochromic luminescence properties. After grinding, the color of the two compounds changes significantly from yellow to orange. [ABSTRACT FROM AUTHOR]

Poly(ε-caprolactone-co-trimethylene carbonate) (PCLTMC) is a biodegradable copolymer, which is widely used for medicine and tissue repair systems, and its morphology, degradation and mechanical properties have been extensively investigated. However, its crystallization behavior with different copolymerization ratios has not been studied systematically, which is of great significance for the study of property regulation and an understanding of the crystallization behavior of random copolymers. In this paper, the relationship between the crystallization temperature Tc, melting point temperature Tm and crystallinity Xc of copolymers with different molar ratios was determined by differential scanning calorimetry (DSC) using a non-isothermal crystallization method. The results show that the melting point and crystallinity of the copolymer decrease with an increase in TMC composition. The equilibrium melting point of the copolymers was predicted by an isothermal crystallization method, using the Hoffman–Weeks extrapolation method and crystallization rate growth fitting method both based on Lauritzen–Hoffman theory. It is proved that Lauritzen–Hoffman theory is of great significance for guiding the kinetic behavior of PCLTMC crystallization. [ABSTRACT FROM AUTHOR]

This paper investigates the synthesis, crystal structure, thermal properties, and energetic performance of two 1D coordination polymers (CPs). The CPs, namely, [Zn(atrz)(DNBA)2(H2O)2]n (1) and [Cd(atrz)(DNBA)2(H2O)2]n (2), were designed and synthesized based on the nitrogen-rich ligand 4,4′-azobis-1,2,4-triazole (atrz) and 3,5-dinitrobenzoic acid (HDNBA) via a mixed ligand strategy using a simple and environment-friendly method. The CPs were characterized by various spectroscopic and analytical techniques along with single-crystal X-ray diffraction (SCXRD). SCXRD analysis reveals a distorted octahedral geometry around the metal ions (Zn/Cd), leading to the formation of a 1D coordination polymer while constructing a 2D structural framework through intermolecular hydrogen bonding. Both the CPs exhibit similar thermal stability but considerably differ in their heat of formation values (1 = −894.43, 2 = 1635.93 kJ mol−1). CP 2 has higher detonation velocity (7.24 km s−1) and pressure (23.67 GPa) compared to 1 (detonation velocity: 6.28 km s−1, detonation pressure: 17.57 GPa) owing to its higher heat of formation and density. Both the CPs exhibit ideal insensitivity to friction and impact stimuli, ensuring their safety during transportation and processing. The value of average activation energy obtained from isoconversion ASTM E698 for 1 and 2 was reported to be 143.8 and 168.0 kJ mol−1, respectively. This study explores the development of energetic CPs through the mixed ligand strategy based on the atrz ligand and incorporating HDNBA as the co-ligand to reduce the sensitivity while maintaining the comparable energetic performance of previously reported atrz-based complexes. This paper also highlights the potential use of CPs as explosives by demonstrating higher energetic performance. [ABSTRACT FROM AUTHOR]

The exploitation of photo-responsive metal–organic frameworks (MOFs) is important in the field of optical switching, advanced detection, and molecular machines. However, it remains challenging due to the heavy dependence on conventional organic photochromic molecules. Herein, a novel photochromic MOF based on benzophenone units, [Zn4(μ2-O)(μ3-O)(cdip)2(DMF)]n (H4cdip = 5,5′-carbonyldiisophthalic acid) (1), has been successfully synthesized. Compound 1 exhibits instant and reversible photochromic behavior under 365 nm UV and X-ray irradiation through the radical formation of benzophenone units. Furthermore, the fluorescence of 1 can be reversibly modulated during the photochromic process. The excellent stability and reproducibility make it suitable for inkless erasable printing paper. [ABSTRACT FROM AUTHOR]

As a new generation of photoelectric materials, organic-inorganic halide perovskites have been widely used in photodetectors, solar cells and other fields, but most of the current mainstream applications are thin film materials. Compared with polycrystalline thin films, perovskite single crystals have fewer grain boundaries and relatively stable electron and hole transport, and are ideal materials for optoelectronic devices. To realize the controllable growth of CH3NH3PbBr3 (MAPbBr3) crystals, understand their growth mechanism, and reflect the inherent physical and chemical properties of the material, a new type of internal growth temperature control and external circulation cooling growth system was developed in this paper, which can accurately control the temperature change during crystal growth. The size of the grown MAPbBr3 single crystal reaches 62 × 58 × 23 mm³, which is the largest single crystal reported to date. The measured single crystal absorption cut-off edge, optical band gap, and carrier lifetime are superior to the traditional simple inverse temperature crystallization (ITC) method, which will help its deep applications in photovoltaics, optoelectronics, and X-ray imaging. [ABSTRACT FROM AUTHOR]

Radical-cation salts of formula β?-(BEDT-TTF)4[(H3O)Fe(C2O4)3]·guest have produced a large number of superconductors and provided a route to introduce magnetism and chirality into the same multifunctional material. A relationship has been found in these salts between the length of the b axis and the superconducting Tc. Increasing the b axis length by introducing larger guest molecules, such as benzonitrile and nitrobenzene, gives the highest superconducting Tcs in this family of salts. Smaller guests such as pyridine show no superconducting transition, whilst asymmetrical guests which are larger than nitrobenzene have given a different bilayered structure. Other potential guest molecules have been limited by their ability to be used as the solvent in which the crystals are grown via electrocrystallisation. This paper reports a method which introduces guest molecules into the crystal which are a solid or liquid additive within the crystal-growing solvent 1,2,4-trichlorobenzene:ethanol. We present the crystal structures of five new BEDT-TTF radical-cation salts with tris(oxalato)ferrate anions using guest molecules toluene, phenol, benzaldehyde, 4-bromobenzaldehyde, and kojic acid. [ABSTRACT FROM AUTHOR]

In this paper, CoMn-layered double hydroxide (CoMn-LDH) was synthesized by the co-precipitation method, and it was applied to activate peroxymonosulfate (PMS) for degradation of bisphenol A (BPA). The results showed that CoMn-LDH with regular morphology and high purity was successfully prepared. The results of BPA degradation experiments showed that the oxidation system had high ability to degrade BPA. The degradation efficiency of BPA reached 95.33% after 90 min at room temperature, pH = 7.0, a PMS concentration of 2.0 mmol L−1 and 0.3 g L−1 catalyst. And the removal rate of total organic carbon (TOC), indicating the mineralization degree of BPA, was 55.83% in 90 min. Finally, the catalytic mechanism of the reaction was preliminarily investigated using radical trapping experiments and X-ray photoelectron spectroscopy (XPS). Free radical trapping experiments showed that OH˙ and SO4˙− radicals were produced in the reaction process, and OH˙ was the main active radical. CoMn-LDH showed excellent stability and reusability in cycling experiments, and had good practical value. [ABSTRACT FROM AUTHOR]

CTGS crystals are widely used in the field of high-temperature piezoelectricity because of their excellent piezoelectric properties. In this paper, the Ca2+ lattice of CTGS crystals is replaced by Sr2+ with a larger radius to improve their piezoelectric properties. (Sr0.2Ca0.8)3TaGa3Si2O14 and Ca3TaGa3Si2O14 single crystals with a diameter of 25 mm were grown using the vertical Bridgman method. The full width at half maximum (FWHM) of X-ray rocking curves of SCTGS and CTGS crystals are 57.6′′ and 22.3′′, respectively. It was found that the thermal properties of SCTGS crystals, such as specific heat, thermal diffusion and thermal conduction, are slightly lower than those of CTGS crystals. At room temperature, the dielectric permittivity ε T11 increased from 18.59 to 18.78, and the piezoelectric coefficient d11 also increased from 4.22 pC N−1 to 4.54 pC N−1. The electrical resistivities of the X-cut plates of SCTGS and CTGS crystals are approximately 3.78 × 107 Ω cm and 2.40 × 107 Ω cm at 800 °C, respectively. Therefore, SCTGS will be a promising candidate piezoelectric material in the field of high-temperature sensing. [ABSTRACT FROM AUTHOR]

Viologen is capable of generating radicals in response to an applied stimulus, giving it an abundance of stimuli responsive properties. However, the radical state of viologen is often unstable, which hinders further studies on the radical properties of viologen. In this paper, the salicylhydrazide group was chosen as a donor group to bond with mono-substituted bipyridyl groups to obtain three novel D–A type viologen compounds. The compounds were harvested and characterized by X-ray single crystal diffraction, optical spectroscopy, EPR and DFT calculation, etc. The results show that compounds 1–3 adopt certain free radical states at room temperature under ambient light, which may be attributed to the electron-donating properties of the salicylhydrazide group and the degree of system conjugation. In addition, compound 1 has a hydrochromic property and compounds 2 and 3 have photocurrent effects under UV radiation. [ABSTRACT FROM AUTHOR]

As a promising candidate to replace lithium-ion batteries, rechargeable aqueous zinc ion batteries (AZIB) are receiving increasing attention due their high energy density, high safety, low cost and environmental friendliness. In this study, metal ions may be introduced into the interlayer gap of layered vanadium oxide nanobelts through a one-step hydrothermal process, without changing their original structure. Moreover, we have demonstrated by density functional theory computations that Mn metal ions not only serve as structural pillars but also enhance the conductivity of MnxVO2·0.2H2O, facilitating the migration of Zn ions. As a result, the electrochemical performance of MnxVO2·0.2H2O as an AZIB cathode has significantly improved; after 100 cycles at 0.5 A g−1, it exhibits a high reversible capacity of 350 mA h g−1. With a high current density of 5 A g−1, the initial capacity can still reach 295 mA h g−1. This paper suggests an effective method to maximize the efficiency of AZIB electrode materials. [ABSTRACT FROM AUTHOR]

The paper discusses the use of ultrasound in separating different polymorphic forms of metacetamol. The study examines the influence of various sonication parameters on the separation process, including nucleation time, morphology, and number of nucleation. The results indicate that lower sonication parameters lead to the nucleation of stable form I, while higher insonation time induces the nucleation of metacetamol hemihydrate. This helps to control the nucleation of stable form I and separate the hemihydrate from pure aqueous solution with reduced nucleation time. In situ optical microscopy was used to confirm the morphology of nucleated polymorphs. Powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) analyses were used to confirm the internal structure and thermal stability of the grown stable form I and hemihydrate crystals, respectively. The study concludes that ultrasonication is a reliable, robust and optimal method that significantly impacts the crystallization and separation of metacetamol polymorphs. [ABSTRACT FROM AUTHOR]

In this work, by using two kinds of viologen ligands, three POM-based compounds were obtained under hydrothermal and solvothermal conditions, namely, {Cu2(Cbybpy)6(Cl)2[H4(β-Mo8O26)3]}·12H2O (1), (HCbybpy)2·(β-Mo8O26) (2) (Cbybpy·Br = 1-(2′-cyano-biphenyl-4-ylmethyl)-[4,4′]bipyridinyl-1-ium bromide) and (HtBbbpy)6·(β-Mo8O26)2·(α-Mo8O26) (3) (tBbbpy·Cl = 1-(4-tert-butyl-benzyl)-[4,4′]bipyridinyl-1-ium chloride). The structures were characterized by FT-IR spectroscopy, PXRD and single crystal X-ray diffraction. These three compounds exhibit dissociative structures, in which there is a bi-nuclear Cu cluster in 1. Compounds 1–3 have a photochromic ability under irradiation of a Xe lamp with a filter (300–400 nm), showing fast photoresponse and different degrees of color change. Therefore, compounds 1–3 can be used in mixed matrix films for visible UV detectors. Compounds 1–3 also have photoluminescence properties with a good fluorescence quenching effect under irradiation. The powder samples of 1–3 can also be simply treated by ultrasonic treatment with ethanol solution and deposited on filter paper, which can be used as inkless and erasable printing materials. Taking compound 2 as an example, we prepared its metal ion detection test paper and realized the visual detection of Hg2+, Cu2+, and Co2+. Compounds 1 and 2 exhibit amine-selective sensing in contact with different amine vapors, so they can be used as organic amine detectors. [ABSTRACT FROM AUTHOR]

This paper focuses on the generation and transformation of defects associated with subsurface damages (SSDs) in seed crystals during the physical vapor transport (PVT) growth of 4H-SiC crystals. SSDs in the 4H-SiC seed crystal were first revealed and labeled through photo-chemical etching. After 30 min of PVT growth on the 4H-SiC seed crystal, we found that ridge-like substances with a height ranging from 0.2 to 1.5 μm were formed in the region above the SSDs in the 4H-SiC seed crystal. Raman spectra analysis indicated that these ridge-like substances were 4H-SiC under tensile strain. We then continued the PVT growth to obtain a 4H-SiC boule and carried out a wafering process to obtain 4H-SiC single-crystal wafers. For the bottom wafer, above the 4H-SiC seed wafer, the full width at a half maximum (FWHM) of the rocking curves of the region above the SSDs of the seed wafer was higher than that in the other regions, indicating that the SSDs degrade the crystalline quality of 4H-SiC single crystal. The average value of the FWHM of the rocking curves of the top wafer became lower than that of the bottom wafer, indicating that the effect of SSDs gradually recovers. Molten-KOH etching indicated that SSDs in the 4H-SiC seed crystal give rise to the formation of low-angular grain boundaries (LAGBs) that consist of a wall of threading edge dislocations (TEDs) in 4H-SiC single crystals. [ABSTRACT FROM AUTHOR]

The sesquioxide Lu2O3 possesses superior physical and chemical properties and emerges as a promising host material for high-power laser applications. However, Lu2O3 has an extremely high melting point, making it difficult to prepare large-size and high-quality crystals. In this paper, we report the growth of a Yb:Lu2O3 crystal with dimensions of Φ50.7 × 43.0 mm3 using the temperature gradient technique (TGT) combined with the directional solidification technique. The full width at half maximum (FWHM) of the high-resolution X-ray rocking curve of the crystal was determined to be 58.76 arcsec. Additionally, the optical homogeneity root mean square (RMS) was 10−5. The thermal properties, spectroscopic characterization, and continuous wave (CW) laser operation of Yb:Lu2O3 crystal were systematically studied. The results demonstrate the efficacy of the TGT as a novel approach for growing large-sized Lu2O3 crystals of exceptional quality. [ABSTRACT FROM AUTHOR]

Transmetalation plays a very important role in the study of functional MOFs, but it is rarely used in metal–organic salts (MOSs). In this paper, four kinds of MOSs were synthesized by using the tetradentate ligand N,N′-bis (pyridin-4-ylmethyl) ethane-1,2-diamine and MCl2 (M = Zn, Co, Cu), labelled as [H4L]4+·2[CoCl4]2−·2H2O (1), [H4L]4+·2[ZnCl4]2−·2H2O (2), [H4L]4+·[CuCl4]2−·2Cl− (3), and [H4L]4+·2[CuCl4(H2O)]2− (4). Salt 3 was obtained by the metal-ion exchange of salt 1, and salt 4 was successfully synthesized by liquid-assisted grinding (LAG) of salt 3 and CuCl2·2H2O, which was a stoichiometric ratio-controlled transformation that occurred with the change in the geometry of copper(II) anions from [CuCl4]2− and [CuCl4(H2O)]2−. The reaction process was monitored dynamically by atomic absorption spectroscopy (AAS), fluorescence spectroscopy, and powder X-ray diffraction (PXRD). This suggested that transmetalation combined with LAG was an alternative method to obtain MOSs for different metal ions. [ABSTRACT FROM AUTHOR]

Given its safer working potential and higher theoretical capacity, Li3VO4 has become a potential alternative anode material to graphite. However, the hydrophilicity, low electrical conductivity, and unsatisfactory reaction kinetics of the Li3VO4 anode pose a challenge. In this paper, a graphene-wrapped Li3VO4@rGO hybrid was prepared using a novel efficient uniform rotation solvothermal (URS) method. Graphene with high electrical conductivity accelerates the reaction kinetics of the anode material to improve its rate performance. The URS method restrains the agglomeration of particles to shorten the diffusion paths of Li+. The uniform reaction obtained by this method and the lamellar shape of graphene synergistically enlarge the specific surface area of Li3VO4 to supply additional active sites for the extraction/insertion of Li+. Therefore, Li3VO4@rGO–R exhibits superior cycling performance (249.5 mA h g−1 after 4000 cycles at 5 A g−1) and rate performance (243.3 mA h g−1 at 10 A g−1). This study provides a versatile and efficient method for enhancing the electrochemical performance of anode materials. [ABSTRACT FROM AUTHOR]

In this paper, the functionalized ligand 2-(imidazole-1-yl)terephthalic acid was obtained by grafting an imidazole group onto 2-bromoterephthalic acid. Then, defective MOFs were synthesized with Hf ions and the ligand in the presence of monocarboxylic acid acting as a modulator, and NHC (nitrogen heterocyclic carbene)–CO2 adducts were grafted onto the Hf-based MOFs to catalyze the cycloaddition reaction of epoxides with CO2 to produce cyclic carbonates under green conditions of ambient pressure and being solvent- and cocatalyst-free. The mesopore defects created by the modulator and DMC (dimethyl carbonate) solvothermal etching, the enhanced Lewis acidity of the Hf clusters and the grafted NHC–CO2 adducts can improve synergistically the catalytic performance of the MOFs via decreasing activation energy, promoting mass transfer and providing more active catalytic sites. The results show that the highest conversion rate reaches 81.64% at 100 °C and 10 h for the cycloaddition reaction of CO2 with epichlorohydrin. Finally, a possible reaction mechanism was proposed based on characterization and catalytic measurement. [ABSTRACT FROM AUTHOR]

This study investigated the relationship between the failure of a silicon carbide (SiC) Schottky barrier diode (SBD) and the corresponding defects on its 4H-SiC substrate and epitaxial layer. The dislocations enlarged by KOH etching and other surface defects of SiC materials were characterized by SICA88, and the linking function of which was used to track the same locations on the 6 inches wafer. This paper statistically showed the type of defect that leads to dead dies that are featured with breakdown points. Results show that 88% of breakdown points on the device were strongly related to single threading screw dislocations (TSDs), or TSD related defects in the substrate. In addition, 77% of the breakdown points would correspond to small pits on the epitaxial layer, that originate from substrate TSDs. In conclusion, substrate TSDs, which inherit and produce pits on the epitaxial surface, have a higher probability to cause SiC SBD breakdowns. Possible reasons for how a TSD can extend and develop into a pit on the epitaxial layer were proposed. [ABSTRACT FROM AUTHOR]

In this paper, the effect of Na+ concentration on the crystalline phase, morphology, and content of vaterite in a system with different Ca2+ and CO32− ratios using steamed ammonia liquid waste as the calcium source was investigated, and the effect of Na+ on the yield of vaterite was studied systematically for the first time. The obtained products were characterized by powder X-ray diffraction (XRPD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, laser particle size analysis (LPSA), and so on. The results show that the variation of Na+ concentration in different Ca2+ and CO32− ratio systems has an effect on the particle size, morphology, content, and CaCO3 yield of vaterite. Thermogravimetric (TG) analysis indicates that Na+ is involved in forming CaCO3 but does not enter the interior of the vaterite crystals. Mechanistic analysis shows that changes in Na+ concentration can alter the initial pH of the reaction system and the conductivity of the solution, thus changing the processes such as early nucleation and crystal growth of vaterite as well as inhibiting the vaterite phase transition, which determines the particle size of the vaterite obtained. This study reveals to a certain extent the influence of Na+ on the early nucleation and crystal growth of vaterite and provides theoretical support for the realization of large-scale industrial production of vaterite. [ABSTRACT FROM AUTHOR]

The high temperature stability of zirconia crystals is improved by regulating the content of the stabilizer Y2O3. Cubic zirconia crystals with thermal stability are one of the most active academic research areas for zirconia crystal materials. Nonetheless, the reason for the discoloration of blue cubic zirconia at high temperatures was not determined. In this paper, the spectra of yttria-stabilized zirconia (YSZ) were investigated, and the local structure regulation was carried out to determine the reasons for the colour instability of crystals at high temperatures. Two kinds of blue cubic zirconia samples with different ZrO2–Y2O3 ratios were heated at 800 °C for 1 hour in an air atmosphere. The structure, optical characteristics, and electron binding energy of cubic zirconia crystals with different ratios before and after heating were compared. Sample A changed colour, while sample B remained unchanged. The amount of Y2O3 stabilizers in sample A is three times higher than that in sample B. The significant shift in the absorption cut-off edge of sample A after heating indicates a reduction in the crystal bandgap. The high temperature discoloration of the crystals is attributed to an increase in oxygen vacancies. The study of XPS, XRD, and Raman showed an increase in the concentration of oxygen vacancies in sample A after heating. The thermoluminescence spectra indicate the depth of oxygen vacancy defects and the increase in defect concentration after heating. [ABSTRACT FROM AUTHOR]

A Cd1−xMgxTe crystal is considered an ideal room temperature radiation detector material due to its excellent opto-electrical properties. In this paper, three large Cd0.95Mg0.05Te ingots with a diameter of 30 mm and a length of more than 100 mm were successfully grown by the modified vertical Bridgman method under different excess Te conditions (0.5 at%, 1.0 at% and 1.5 at%). The results showed that the as-grown Cd1−xMgxTe crystals have cubic zinc-blende structures. The band gap of the crystals ranged from 1.43 eV to 1.52 eV, the density of Te inclusions ranged from 2.7 × 103 cm−2 to 1.0 × 105 cm−2, the resistivity ranged from 8.22 × 106 Ω cm to 1.51 × 1010 Ω cm, and the IR transmittance ranged from 33% to 60%. With the increase of excess Te, the band gap, crystal resistivity and infrared (IR) transmittance decreased, and the density of Te inclusions increased. The analysis of the low temperature photoluminescence (PL) and Raman scattering spectra indicated that the crystal quality deteriorated gradually with the increase of excess Te. The crystal grown under 0.5 at% excess Te conditions had the best optical and electrical properties. [ABSTRACT FROM AUTHOR]

In general, β-Ga2O3 films with (2¯01) out-of-orientation have been widely obtained and reported on (0001) sapphire substrates by various growth methods. In this paper, the unusual (3¯10)-oriented β-Ga2O3 films have been epitaxially grown on (0001) sapphire substrates with high crystal-quality under Ga-rich conditions by halide vapor phase epitaxy (HVPE). The out-of-plane epitaxial relationship as (3¯10) β-Ga2O3//(0001) α-Al2O3 has been confirmed by XRD and HRTEM analysis. Under most growth conditions, β-Ga2O3 films exhibit the coexistence of (3¯10) and (2¯01) out-of-plane orientation domains, and increasing the growth temperatures and HCl flow-rates can enhance the growth of (3¯10)-oriented β-Ga2O3. Off-angled (0001) sapphire substrates with off-angles (Δa) toward 〈112¯0〉 have been introduced to control the in-plane domains. It was indicated that the (2¯01)-oriented domains have been gradually eliminated with increasing the off-angles, and pure (3¯10)-oriented β-Ga2O3 films with the best crystal quality reported so far have been obtained while the off-angle was ∼7°. The decrease of the domain boundaries and defects caused by the in-plane rotational domains have led to the improvement of the crystal quality of the as-grown films. [ABSTRACT FROM AUTHOR]

In this paper, we present the synthesis and characterization of a Cl-bearing member of the phosphate family of compounds with a tetragonal crystal structure and similar topology in the basic projection. The title compound was obtained under hydrothermal conditions and its crystal structure was determined by single crystal low temperature X-ray diffraction. The structure of NaCo7.38(PO4)4Cl4 is formed with CoO4Cl2 octahedra sharing faces and assembled into eight-component ring clusters with a very short Co–Co distance of 3.014 Å. These clusters are linked in a three-periodic network via vertex-bridge contacts of adjacent octahedra and PO4 tetrahedra. Na atoms occupy the open channels of the framework. The structure is discussed as a derivative of cubic sulphohalite, Na6(SO4)2ClF, with the symmetry lowering from the widespread Fm3¯m space group of sulphohalite to the tetragonal acentric space group I4¯2m in our case; these space groups are symmetrically related by subordination "group → subgroup". Theoretical calculations of possible pathways of Na migration through the framework showed that although the structure contains a sufficient number of voids for sodium ions, their migration is limited by the size of the channels. However, the obtained results indicated that the migration of Li+ ions is very likely through a two-periodic network parallel to the ab plane, which means that Li-containing structural varieties of NaCo7.38(PO4)4Cl4 with possible formulae Li5Co2+Co3+3(PO4)4Cl4 or Li4Co3+4(PO4)4Cl4 can possess ionic conductivity. The angle of intracluster Co–O–Co bonds of 105.4° allows us to assume that there is an antiferromagnetic exchange interaction between the Co atoms, and we assume that the intercluster exchange interactions between Co2+/3+ ions through the intermediate PO4 groups are also probable. [ABSTRACT FROM AUTHOR]

The structure–property relationship is always the focus when organic light-emitting materials are used mainly in the aggregated state in some fields, such as optoelectronic devices, sensors, and bioimaging. To clarify a clear structure–property relationship between the aggregate structure and the luminescent property, the intermolecular dimer, which represents the smallest aggregate in a number, is selected as an ideal research model. However, how to achieve an intermolecular dimer by a rational molecular design is rarely found in previous papers in this field. Here, we design and synthesize three pyrene derivatives, aiming at achieving the pyrene-based dimer in a solid state, by bridging pyrene and benzo[d]thiazole (BZT) in a different position on a phenylene. The pyrene and BZT groups are connected with each other in the ortho-, meta-, and para-positions of the phenylene to construct three molecules Py-oBZT, Py-mBZT, and Py-pBZT. Experimental and theoretical investigations demonstrate that only Py-oBZT shows pyrene-based dimer stacking with a discrete feature due to the large steric hindrance provided by the BZT group. Compared to individual pyrenes in the crystal, the pyrene-based dimer in the Py-oBZT crystal exhibits a different molecular orientation, which is verified by the presence of multiple potential wells of the pyrene dimer using a theoretical simulation of the potential energy surface. This work not only examines the effect of steric hindrance on the formation of the pyrene dimer packing, but also provides an understanding of the multiplicity of the pyrene dimer structures. [ABSTRACT FROM AUTHOR]

Molecular-based dielectric switching materials are special crystal–crystal structure phase transition materials, and play an important role in multifunctional materials and other fields. In this paper, a trivalent cyclic amine is used as the building unit to successfully prepare a molecular crystal material, 1,4,7-triazacyclononane trihydrochloride, 1, with abundant hydrogen bonds and high temperature dielectric switching properties, and its IR, TGA, DSC, VT-PXRD (variable-temperature PXRD), VT-structures, and T–ε′ (temperature dependence of the real part of the dielectric constant) are characterized and analyzed. The space group of 1 is P21/n at 298 K and R3¯m at 403 K. Two endothermic peaks appeared near 369 K and 380 K and one exothermic peak appeared near 363.5 K in the DSC heating–cooling cycle test. In the vicinity of the corresponding phase transition temperature, 1 shows an obvious reversible change of dielectric plateau and small dielectric loss. The dielectric switching cycle curves show that 1 has good dielectric switching performance. All of these interesting physical properties are closely related to the reversible order–disorder states of cations and anions in the molecule. This work shows that 1 is a switchable dielectric molecular crystal material with broad application prospects, and provides a new route for design and synthesis of switchable dielectric materials with excellent properties. [ABSTRACT FROM AUTHOR]

This paper describes our findings on the molecular association patterns of seven hexacoordinated Sn(IV)(axial-L)2-(5,10,15,20-tetraiodophenylporphyrin) complexes [where L = F-substituted benzoate anions]. The systematic and progressive variation of the fluorine content on the molecular scaffold resembling a rigid wheel-and-axle duo demonstrates that it is possible to induce I⋯F hetero-halogen interactions among other weak interactions such as C–H⋯O, C–H⋯π, π⋯π etc. Hirshfeld surface analysis further supports the role of hetero-halogen interactions in the model compound 6. DFT-based electrostatic potential surface studies show the presence of a σ-hole on the iodine atom and thus vouch for its electrophilic nature in all the observed I⋯F halogen bonds. A homo-halogen I⋯I contact with much non-linearity is observed in 7, and, conspicuously, no F⋯F is found in any of the structures studied due to the hard nature of the fluorine atom. Quantum theory of atoms in molecules (QTAIM) analysis clearly reveals the presence of bond critical points, thus confirming the existence of homo- and hetero-halogen bonds within the studied dimer. Further support for the attractive nature of homo- and hetero-halogen bond interactions is gathered through noncovalent interaction-reduced density gradient (NCI-RDG) analysis, which shows the attractive nature of such interactions. Overall, the combined experimental and theoretical studies presented here showcase the occurrence of both homo- and hetero-halogen interactions and their role in the self-assembly process and associated photophysical properties of metalloporphyrin complexes. [ABSTRACT FROM AUTHOR]

The exploration of proton-conducting solid-state electrolytes operating under humidified conditions is currently of considerable significance for fuel-cell technology. However, the effect of the hydrophilicity of various hydrophilic groups in materials on the proton conductivity remains unknown. Metallo-hydrogen-bonded frameworks (MHOFs) provide a promising alternative for solving this difficult problem due to their versatile functional groups, easy-to-identify structures, tunable functionalities and good chemical stabilities. In this paper, we designed and synthesized two MHOFs with similar chemical structures, [Co(PPA)2(H2O)2(NCS)2·2H2O] (Co-2PPA) and [Co(PPA)4(NCS)2] (Co-4PPA) (PPA = 4-(3-pyridinyl)-2-amino pyrimidine), to elucidate the issue. Indeed, Co-2PPA and Co-4PPA show remarkably distinct proton conductivities due to the presence of different hydrophilic groups, which are 2.96 × 10−4 and 2.78 × 10−5 S cm−1 at 333 K and ∼97% RH, respectively, approaching one order of magnitude. We found that the difference in proton conductivities between Co-2PPA and Co-4PPA is primarily correlated with the different water uptake of the samples. The results originate from the different hydrophilic affinity between hydrophilic groups (H2O and –NH2) in MHOFs and adsorbed water molecules, i.e., the more similar the structure between hydrophilic groups and water molecules, the greater the hydrophilicity, the higher the water uptake, the better the proton conductivity, following the "like-attracts-like" rule. Furthermore, frequency- and temperature-dependent dielectric spectroscopy measurements reveal that there exists proton transfer along hydrogen bonds in Co-2PPA and Co-4PPA, obeying the Grotthuss proton-hopping mechanism. Notably, different changes in hydrogen bond lengths of Co-2PPA and Co-4PPA with increasing temperature are responsible for the various Ea values for proton conduction. This work gives an attractive idea for designing solid-state proton conductors and investigating the proton-conducting mechanism. [ABSTRACT FROM AUTHOR]

High-quality seeding is the key to ensure the preparation of high-quality sapphire single crystals. The strength and direction of the melt flow control the crystal seeding shape and bubble movement and will directly affect the quality of crystal seeding. To improve the crystal seeding quality under complex convection, based on the lattice Boltzmann method, an optimization method of seed crystal rotation was proposed before crystal seeding, and the unsteady melt flow rate, internal temperature of the melt and crystal rotation speed were calculated and analyzed. The coupling relationship between the Grashof number and the Reynolds number is analyzed. The results show that the optimization method of crystal rotation can effectively restrain the convection of the melt and improve the temperature distribution on the surface of the melt. Compared with the multi-frame intercomparison visual inspection detection method and artificial seeding method, the method proposed in this paper is helpful to improve the quality of sapphire seeding. [ABSTRACT FROM AUTHOR]

The optical properties and potential applications of metal nanostructures are mainly related to the unique surface plasmon resonance (SPR) effects that highly depend on the morphology, composition, assembly style and surrounding medium of metal nanostructures. Compared with monometallic nanoparticles, bimetallic composite nanostructures exhibit improved physicochemical properties. In this paper, the preparation and performance study of core–shell Au@Ag nanocuboids and open Au@Pd nanoframes were carried out based on Au nanorods with different aspect ratios. The co-reduction method was applied to control the deposition of Ag atoms on the surface of Au nanorods to obtain Au@Ag nanocuboids. The nanocuboids have flat surfaces and exhibit an adjustable SPR effect in a wide spectral region. Moreover, they show an ultra-sensitive response to the change of the surrounding medium. The refractive index sensitivity of the Au@Ag nanocuboids is better than that of the Au nanorods. Due to the rich edges and sharp corners, this Au@Ag nanocuboid structure can also be used as a hard template for further growth of highly active nanoframes. Then we controlled the deposition of Pd atoms on the surface, especially the edge parts, of Au@Ag nanocuboids. A new nanostructure of open Au@AgPd nanoframes was constructed after selectively etching the Ag shell. These open nanoframes not only show strong SPR properties similar to Au nanorods, but also exhibit excellent catalytic performance in the electrocatalytic reaction of ethanol. This work provides an idea for designing efficient sensors and nanocatalysts. [ABSTRACT FROM AUTHOR]

The development of a bifunctional ruthenium-based electrocatalyst that can efficiently and economically drive both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) remains challenging because ruthenium species can undergo severe agglomeration during preparation which can significantly reduce the catalytic activity. Constructing supported metal catalysts can not only improve the stability of Ru but also improve the catalytic performance by adjusting the electronic structure, which is an effective way to solve the current challenges. In this paper, Ru-loaded MoO2/MoO3 heterostructures (Ru–MoOx) with oxygen vacancies were successfully synthesized by controlling the annealing temperature. This special structure can effectively tune the electronic structure, enhance the electrical conductivity and increase the active sites, thus improving the catalytic activity of the catalyst. Performance studies have shown that Ru–MoOx exhibits excellent HER and OER performance in alkaline media. And it is not surprising that the overall water decomposition performance of Ru–MoOx is also excellent, requiring only a cell voltage of 1.54 V to reach 10 mA cm−2. [ABSTRACT FROM AUTHOR]

The development of high-performance and cost-effective electrocatalysts for the oxygen evolution reaction (OER) is critical to renewable energy conversion and storage technologies. Among of them, metal organic frameworks (MOFs) have been proved to be effective substitutes for precious metals. In this paper, a series of mixed NiCoFe-MOFs with low crystallinity were synthesized by a simple one-step solvothermal method, which can be used as a direct electrocatalyst for the OER. Notably, the flower-like nanocatalyst NiCoFe-MOF-2 exhibits a hierarchical pore network and a large specific surface area (149.6 m2 g−1), which results in an adjustable electronic structure, effective mass transfer, and abundant exposed active sites. In addition, due to the synergy between the three metals Fe, Co and Ni, NiCoFe-MOF-2 can exhibit excellent electrocatalytic OER performance, with a low overpotential of 321 mV at 10 mA cm−2, superior to commercial RuO2 (379 mV), a Tafel slope of 48 mV dec−1 and long-term stability. The result may stimulate more designs of MOF-derived catalysts with multi-scale structures and multi-components designed for various electrochemical energy conversion devices. [ABSTRACT FROM AUTHOR]

In this paper, a series of coordination polymers, {[Zn(adb)(L1)2]·solvent}n (L1 = solvent = N,N-dimethylacetamide, Hui-3-DMA; L1 = N,N-dimethylformamide and no solvent, Hui-3-DMF; L1 = N,N-diethylformamide and no solvent, Hui-3-DEF) have been synthesized by hydrothermal reactions of Zn(NO3)3·6H2O and 4,4′-(anthracene-9,10-diyl)dibenzoic acid (H2adb). These compounds show similar one-dimensional (1D) zig-zag chain structures, which are limited by the end-coordination of the solvent molecules. Interestingly, these compounds all show blue-emission properties, which could be easily modulated by using different solvents. Among them, Hui-3-DMA presents an excellent quantum yield performance, as high as to 54.1%, which is very promising for blue-emission materials. Moreover, various-temperature fluorescence studies reveal good linear or exponential decline trends for their emission intensity as temperature increases, demonstrating the potential of these compounds as fluorescent thermometers. [ABSTRACT FROM AUTHOR]

In this paper, the geometric structures and electron-optical properties of AlAs/GaS heterojunctions and Se-doped AlAs/GaS heterojunctions are calculated based on first-principles of density functional theory (DFT). At the same time, the influence of the AlAs layer's 5° rotation stacking method on the AlAs/GaS heterojunction is discussed. The results show that the AlAs/GaS heterojunction is a type-II van der Waals heterojunction (vdWH) with a direct bandgap of 0.974 eV, and the Z-scheme electron transfer mechanism is more conducive to the separation of photogenerated electrons and holes. Both semiconductor-to-metal transitions can be achieved by applying an external electric field and strain. Under the action of an external electric field and uniaxial strain, AlAs/GaS maintains the type-II energy band alignment throughout the process. When biaxial strain is applied, the heterojunction is accompanied by a direct–indirect bandgap transition. It is worth mentioning that the optical absorption of the AlAs/GaS heterojunction is significantly higher than that of the two monolayers, and the absorption range is wider. The above characteristics indicate that the AlAs/GaS heterojunction has wider applications in fields such as photodetectors. [ABSTRACT FROM AUTHOR]

Nucleation (or induction) time, the time elapsed from the instance of creation of supercooling a solution to the instance of detection of a first nucleation event, differs widely in a stochastic manner when samples are small like droplets. The nucleation time distributions Pr(t) are closely related to primary nucleation rates. Many attempts have been made to estimate primary nucleation rates from Pr(t). When the plot of ln Pr(t) vs. t is not linear, primary nucleation rates have never been estimated successfully, although these non-linear plots are frequently encountered in reality. This paper proposes a new method for estimating primary nucleation rates from non-linear Pr(t) distribution data. Primary nucleation rates were extracted by analyzing literature data of Pr(t) distributions. The extracted nucleation rates were heterogeneous ones. The relevance of mononuclear-mode nucleation in small samples to polynuclear-mode nucleation in large industrial-scale crystallizers is discussed theoretically. [ABSTRACT FROM AUTHOR]

The signs of the extrema of the molecular electrostatic surface potential (MESP) are an effective means of probing the surface reactivity behavior of molecules. They determine the electrophilicity and nucleophilicity regions, which collectively explain why one polar region of the surface of a given molecule attracts another region of opposite polarity in the same or in a neighboring molecule, resulting in the formation of molecular complexes or supramolecular assemblies in large-scale chemical systems. The chemical systems discussed in this paper are derivatives of fullerenes, carbon nanotubes and a few allotropes of graphene, that have been extensively explored, both theoretically and experimentally, to form a variety of functional materials for application in various fields of chemistry, biology, and polymer and nanomaterials science. We show, using the MESP model, that these highly-valued delocalized systems feature electron-rich and electron-deficient π-regions that can be regarded as negative and positive π-holes, respectively. The former and latter may be regarded as efficient π-hole acceptors of electrophiles (viz. a hydrogen bond) and tetrel bond donors, respectively, when in close proximity with the same or different chemical systems in the crystalline phase. The appearance of negative regions on the surface of the C＝C bonding region of the chemical systems considered for investigation was found to be consistent with the relatively large delocalization index of the corresponding bond, revealed using the quantum theory of atoms in molecules. Some dimers of C20, C60 and C70 fullerene systems with commonly known diatomic molecules (N2, CO, HX and X2 (X = F, Cl, Br) and F2, etc.) are investigated to illustrate the concept developed above. [ABSTRACT FROM AUTHOR]

Crystallization is an important unit operation in industry, and proteins are widely studied owing to their biological activity and multiple functions. Protein crystals can not only facilitate the elucidation of protein structural information but also have important prospects in biopharmaceuticals. However, owing to their high molecular weight and complex structure, most proteins are difficult to crystallize or the crystallization processes are difficult to control effectively. This paper aims to provide an overview of recent reinforcement techniques for protein crystallization. Several important additive applications and principles in protein crystallization are comprehensively reviewed, including ionic liquids (ILs), deep eutectic solvents (DESs), and molecularly imprinted polymers (MIPs). The mechanism of external fields, including magnetic, electric, ultrasonic, shear, and light fields, enhancing protein crystallization are described and summarized. Finally, the challenges and future research prospects of protein crystallization are proposed. This work is expected to guide the rational design of the protein crystallization process. [ABSTRACT FROM AUTHOR]