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[Display omitted] • A green Ultra-High Performance Concrete (UHPC) is proposed in this study. • The phosphogypsum aggregate is included in the UHPC development. • The effects of phosphogypsum aggregate on UHPC properties are studied. • The water migration process of phosphogypsum-based UHPC is presented. • The microstructure of phosphogypsum-based UHPC is clarified. This paper presents an effective method for producing green ultra-high-performance concrete containing phosphogypsum aggregates to meet the demand for a sustainable environment. More exactly, the low field nuclear magnetic technology (LF-NMR), nanoindentation, and Backscattering images (BSEM) are used to clarify the hydration process and microstructure evolution of phosphogypsum-based ultra-high performance concrete (PG-UHPC). The results indicate that the mechanical performance of PG-UHPC decreases slightly as phosphogypsum aggregate content increases, but it is still capable of meeting the requirements of applications. Moreover, the introduction of phosphogypsum aggregate in UHPC accelerates water migration and directly affects its hydration degree. Lastly, a reasonable sulfur content can limit the degradation of interfacial transition zone and reduce the risk of matrix cracking in PG-UHPC. To conclude, advanced composite building materials with low environmental burden are prepared as a reference for the development of green ultra-high-performance concrete. [ABSTRACT FROM AUTHOR]

This study aims to clarify the absorption-desorption process of internal curing water by pumice in ultra-high-performance concrete (UHPC) system based on relaxation theory. More exactly, the dynamic migration process of water from pumice in UHPC and its micro/macro properties are analyzed by 1H nuclear magnetic resonance, backscattering electron, nanoindentation, etc. The results reveal that the prewetted pumice could delay the water release time for 1 h compared with dry pumice (5.5 h), and can continue to absorb about 14% of free water from the end of the mixing process to the beginning of water release. Notably, the release rate of water from prewetted pumice in UHPC is up to 80%, which is beneficial to the alleviation of internal relative humidity decline rate and thus reduces the autogenous shrinkage of UHPC. In addition, the use of prewetted pumice improves the microstructures of UHPC, where compared with river sand, its transport distance of water entraining reaches at 35 μm–55 μm and its interfacial transition zone (ITZ) structure is also denser. Finally, a relaxation theory-based dynamic model is successfully established, which can be used to illustrate the water migration process and predict migration distance in the UHPC system. [ABSTRACT FROM AUTHOR]

• A novel strategy for MT activation is proposed. • An appropriate proportion between MT and ARCW is suggested. • The properties of the developed green UHPC are analyzed. • The microstructure of the developed green UHPC is presented. This paper presents an efficient way to produce Ultra High-Performance Composites (UHPC) with Molybdenum tailings (MT) based on a green activation approach. Firstly, the modified Andreasen & Andersen particle packing model is carried out to obtain a densely compacted UHPC matrix. After that, the MT and an activator recycled from construction waste are included into the UHPC. Besides, the fresh and hardening properties of the newly designed UHPC are evaluated. The obtained results can be summarized as follows: Firstly, an appropriate proportion between MT and the activator recycled from construction waste (0.07–1.5 μm) can effectively reduce the porosity of the UHPC matrix, which guarantees its excellent mechanical properties and durability, then, with the activation reaction going on, the accumulated heat release of the matrix decreases, and the autogenous shrinkage is restrained, which reduces the early cracking risk of UHPC, finally, based on the proposed green activation approach, an advanced building composite with superior properties and low environmental burden could be produced. [ABSTRACT FROM AUTHOR]

This study aims to clarify the hydration kinetics and microstructure development of ultra-low water binder ratio cementitious composites (ULCC) at cryogenic temperatures based on experimental and numerical approaches. More exactly, the micro and macro properties of ULCC are firstly investigated by experiments and then the hydration mechanism is analyzed by NMR and molecular dynamics methodology. The results reveal that the hydration of ULCC can still be triggered at −20°C, while the hydration process is significantly delayed and the theoretical maximum hydration degree drops to 59.72 % of room temperature. When the temperature is further reduced to about −80°C, the hydration of ULCC is prevented, while the crystallization of the original product and the C-S-H chain length is decreased. However, in this case, the hydrogen bond stability of water between layers of C-S-H gels is improved, which can be confirmed by molecular simulation. Finally, a hydration kinetic model is constructed to quantitatively predict the development of water migration process and hydration degree in ULCC at freezing temperature. [Display omitted] • The application of cementitious materials at low temperatures is enriched. • A kinetic model for the hydration of ULCC under low-temperature conditions is established. • The process of moisture migration and ice crystal growth during freezing is visualized. • Low-temperature treatment enhances the shear and tensile stresses between layers of C-S-H. [ABSTRACT FROM AUTHOR]

This study aims to establish a development model for the compressive strength of 3D printed concrete (3DPC) under the coupling influence of temperature and humidity, utilizing the maturity method. Initially, diverse curing conditions were applied to 3D printed specimens, incorporating varying temperatures (10 °C, 20 °C, 40 °C) and relative humidity levels (100% RH, 80% RH, 60% RH, 40% RH), with strength value assessed at different ages. Subsequently, a maturity model for humidity modification was proposed, and the model was calibrated through experimental results. The results show that the strength of the specimens increases over time, irrespective of the variations in curing temperatures and humidity levels. Moreover, with a decrease in humidity level, a more pronounced decline in strength is observed. Furthermore, the anisotropy index values of the rate constant in the Y-direction specimen, when cured at temperatures of 10 °C and higher humidity conditions, such as 100% RH and 80% RH, exhibit significant variations across different temperatures and moisture levels, leading to increased anisotropies. The modified maturity model can be used to predict and evaluate the strength development of 3D PC under different environmental conditions with high accuracy. • Low temperature and high humidity conditions lead to increased anisotropic behavior. • The proposed model accurately predicts the strength development of 3DPC under various temperature and humidity conditions. • The anisotropy index exhibits notable variations across different temperatures and humidity levels. [ABSTRACT FROM AUTHOR]

Cr 2 Ge 2 Te 6 is a rare layered ferromagnetic semiconductor that represents a promising material for novel thermoelectric and spintronic devices. High pressure is an effective way to change the electronic structure, and profoundly affects the physical and chemical properties of two-dimensional (2D) layered materials. Here we combined experimental results and theoretical calculations to investigate the structural evolution and properties of Cr 2 Ge 2 Te 6 under high pressure. It is found that Cr 2 Ge 2 Te 6 undergoes an isostructural phase transition from layered to non-layered structure at ~14 GPa, accompanied with a semiconductor to metal transition, which is distinct from the previous reports. The pressure-induced metallization is verified by the overlap of the valence and conduction bands, and the layered-to-non-layered isostructural transition is attributed to the enhanced interlayer Te–Te interaction by First-principles calculations. Our results provide a potential pathway to control the structure and property of layered materials and possibility for conceptually new devices via pressure engineering. • Cr 2 Ge 2 Te 6 undergoes an isostructural phase transition at ~14 GPa, and accompanied with a semiconductor to metal transition. • The semiconductor-to-metal transition was verified by IR and electrical experiments. • The metallization mechanism was interpreted by theoretical calculations. [ABSTRACT FROM AUTHOR]

With the development of solid-state lighting, full-spectrum lighting has gradually received extensive attention. Until now, Bi3+-doped narrow-band blue phosphors have been widely reported, but broadband green-yellow Bi3+-doped luminescent materials generated by metal-to-metal charge transfer have been rarely reported. In this study, a Bi3+ ion doped germanate luminescent material CsAlGe2O6:x%Bi3+ (1 ≤ x ≤ 11) is synthesized by a high-temperature sintering method. The phosphor can generate a broad green-yellow band peaking at 535 nm with a full width at half maximum of 165 nm under ultraviolet radiation. Through the analysis of the coordination environment, photoluminescence spectra and decay curves, the broadband emission spectra of Bi3+ ions are proved to be generated by the metal-to-metal charge transfer state and the 3P1 → 1S0 transition. By using theoretical research, luminescence kinetics, and Gaussian fitting, the luminescence mechanism of Bi3+ is examined. Meanwhile, the high quantum efficiency and superior thermal stability prove that the phosphor can be used as an efficient luminescent material in the field of full-spectrum LED devices. [ABSTRACT FROM AUTHOR]

This study establishes the fractal evolution model of proton spatial distribution in low water/binder cement-based composites (LW/B-CC) based on fractal theory and low field nuclear magnetic resonance (LF NMR) technology. The results show that the fractal evolution process of gel water, capillary water and surface water distributions in LW/B-CC presents three stages: the first 4–6 h after the beginning of hydration, 4–6 h to 12 h, and 12 h to long-term stage. In the first and second stages, the fractal dimensions of gel and capillary water increase linearly with hydration time, while the fractal dimension of surface water decreases linearly. The boundary is a sudden change of fractal dimensions after about 4–6 h of hydration. The third stage starts after about 12 h of hydration, at which time the fractal dimensions begin to converge to fixed values. Besides, this study reveals the mathematical relationship between fractal dimension (D f) and particle size distribution modulus (q), which is conducive to achieve the full-cycle regulation of LW/B-CC. [Display omitted] • T 2 distributions of 1H in LW/B-CC mortar with different W/B are obtained. • Fractal dimensions of gel, capillary and surface water distributions are calculated. • Change curves of fractal dimension with hydration time are divided into 3 stages. • Fractal evolution model of microstructure for LW/B-CC is proposed. • Pore fractal model and Particle packing model for LW/B-CC are unified. [ABSTRACT FROM AUTHOR]

• CaIn 2 S 4 /TiO 2 nanocomposites were fabricated by a two-step hydrothermal process. • The structure and morphology of CaIn 2 S 4 /TiO 2 heterostructures were characterized. • The CaIn 2 S 4 /TiO 2 heterostructures exhibited efficient MO degradation activity. • The possible Z-scheme photocatalytic reaction mechanism was revealed. Semiconductor heterostructures are regarded as an efficient way to improve the photocatalytic activity. Herein, novel Z-scheme CaIn 2 S 4 (CIS)/TiO 2 heterostructures photocatalysts were synthesized by a simple two-step hydrothermal approach. Compared with single phase nanostructures of TiO 2 and CIS, the CIS/TiO 2 -0.05 g nanocomposites exhibited efficient and stable photocatalytic activity, with 97% of methyl orange (MO) decomposed within 30 min under UV–visible light irradiation. In addition to increased broad light absorption, the outstanding photocatalytic performance is mainly attributed to intimate contact and matched energy band positions between CIS and TiO 2 , which efficiently produce more active electrons and holes, reduce the photogenerated electron-hole recombination, and boost photoinduced charge carrier transfer. The possible Z-scheme mechanism for the photocatalytic reaction in the system was reasonably proposed. This work would arouse an increasing interest in designing more Z-scheme heterojunction photocatalysts with high efficiency for the application of photodegradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Structure transformation of confined water and framework compressibility of hydrated AlPO 4 -11 are studied. • Water transforms to unsaturated configurations from saturated tetrahedral structure upon compression. • Hydrated AlPO 4 -11 exhibits an unexpected high compressibility in Ar relative to that in silicone oil. • The complex Ar-H 2 O and H 2 O-framework interaction after Ar penetration is responsible for the abnormal compressibility. The behaviors of water under non-ambient conditions, especially in confinement environment, have long been of special interest due to the important roles in biological and geological processes. Here, we have performed an infrared spectroscopic investigation on the pressure-induced hydrogen-bond transformation of water in one-dimensional, elliptical channels of AlPO 4 -11. Upon compression, the hydrogen-bonds of confined water strengthen and water molecules transform from tetrahedral coordination configuration to low and intermediate configurations, which may be a high-density disordered state. This transformation is distinct from the commonly accepted liquid–solid and solid–solid phase transition in bulk water. Stronger hydrogen-bonds are formed and a further transformation of hydrogen-bonded water takes place in the hydrostatic environment of Ar than the case without pressure transmitting medium (PTM). In addition, the mechanical compressible behaviors and framework deformation of the host matrix are also discussed. X-ray diffraction study shows that the hydrated AlPO 4 -11 exhibits an unexpected high compressibility in Ar. Its bulk modulus before framework collapse is 14.1 GPa, 4 ∼ 5 times smaller than that in silicone. The anisotropic axial compressibilities of AlPO 4 -11 demonstrate that the ellipticity of the channel cross-section increases in silicone oil while it decreases in Ar because the relatively contractive behavior along minor axis direction is slowed down. Such pressure-induced responses are ascribed to the complex Ar-H 2 O-framework interaction after Ar penetration. This study offers us a new knowledge of crystal-fluid interaction in determining the mechanical behaviors of open-framework materials under high pressure and provides implications for the water evolution and circulation in water-carrying natural zeolites under extreme geological conditions in nature. [ABSTRACT FROM AUTHOR]

[Display omitted] • The structures and low temperature behaviors of confined water in AlPO 4 -11 are studied. • Ice-like tetrahedral configuration, liquid-like structures, coordinated and relatively free water are found. • Small oligomers and low-density water with stronger hydrogen bonds appear at low temperatures. • Both the interface interaction and nanoconfinement effects play important roles. The interfacial and confined water have long been attractive objects due to their crucial roles in biological, geological processes, etc. In this paper, we investigate the hydrogen-bonded structures of water and their low temperature transitions in the subnano channels of AlPO 4 -11 for the first time on the basis of infrared spectroscopy. The number of the adsorbed water molecules is estimated to be 8.45 per channel in one unit cell by thermogravimetric analysis. It is found that the confined water molecules are involved in saturated and unsaturated coordination with different hydrogen bond strengths at ambient temperature. The former refers to ice-like four-coordinated water and the latter includes liquid-like structures, Al-coordinated and relatively free water molecules. Unique coordination between water molecules and framework Al sites is responsible for the ice-like structures in the channels above the ice melting point. The appearance of liquid-like structures is closely related to the strong channel confinement, which does not allow the formation of extensive tetrahedral hydrogen-bonded configuration. As temperature decreases, a structural transformation of confined water happens in the channels of AlPO 4 -11. Isolated small water oligomers and two new components with stronger hydrogen bonds, such as low-density amorphous ice-like structures and a kind of low-density liquid-like structures are preferred. Our results provide important insights into the structural organizations and thermal-dynamic behaviors of confined water in extreme narrow channels. [ABSTRACT FROM AUTHOR]

• Time-dependent infrared spectra of hydrated AlPO 4 –5 are studied. • Low, intermediate and strong hydrogen-bonded water structures are present in the channels. • The hydrogen bonds of unsaturated coordinated water strengthen upon water adsorption. • Water molecules in intermediate coordination transform to tetrahedral structures. • The water-framework interaction facilitates the closure of Al-O-P angles and framework contraction. The structures of the adsorbed water molecules in AlPO 4 –5, their structural evolutions and changes of Al-O-P angles between tetrahedra upon water adsorption were investigated by infrared spectroscopy. The results indicate that Al-H 2 O coordination is present in the channels and the adsorbed water molecules are in low, intermediate and strong hydrogen-bonded environments. The population of the water species varies with a sudden enhancement from 70–140 min, showing similarity to the reported abnormal isotherm due to the increase of host-guest interaction sites. This large-scale uptake of water accelerates structural transformations of water from intermediate to strong hydrogen-bonded structures. Moreover, the water-framework interaction facilitates the closure of Al-O-P angles and thus results in the framework contraction. This study opens the door to a good knowledge of the hydrogen-bonded structures of H 2 O and framework deformation in hydrated AlPO 4 –5 from the viewpoint of infrared spectroscopy. Water molecules in AlPO 4 –5 are in low, intermediate and tetrahedrally coordinated hydrogen-bonded structures. The population of the latter increases at the expense of the intermediate coordinated water and subsequent adsorbed water molecules. The Al-O-P angles in the framework close upon water adsorption. [Display omitted] [ABSTRACT FROM AUTHOR]

We have investigated the pressure‐induced behaviors of nitrogen confined in the zero‐dimensional cavities of zeolitic imidazolate framework (ZIF)‐8 using Raman spectroscopy. Pressure forces the nitrogen molecules in the pressure‐transmitting medium (PTM) to enter the inner pores of ZIF‐8, and two Raman bands attributed to the nitrogen molecules interacting with the framework of ZIF‐8 and those approximately in the central part of the cavities surrounded by the former are observed. The confined nitrogen species transform in a different way under high pressure from those of the bulk nitrogen and the confined nitrogen in the one‐dimensional inorganic channels. Both the intermolecular interaction and the host–guest interaction jointly contribute to the transformation and a highly disordered and densely compressed state of the confined nitrogen is formed at 20 GPa. A hysteresis is found when comparing the Raman spectra at low and industrially accessible pressures after a compression and decompression cycle, suggesting that the ability of ZIF‐8 to storage nitrogen molecules increases. This study opens a new path toward understanding new behaviors of nitrogen in the nanostate and applications of ZIF‐8 for gas storage and capture. [ABSTRACT FROM AUTHOR]

Abstract Ordered hierarchical structured films are considered promising photoanodes for high-performance water-splitting because of their large surface area for light absorption and excellent charge transfer process. In this paper, a novel hierarchical structured photoanode based on growing TiO 2 on a Si nanowire substrate and coupling with Fe 2 O 3 nanothorns was designed and fabricated via a simple method to obtain photoelectrochemical (PEC) properties. The Fe 2 O 3 /TiO 2 /Si nanowire arrays (NWs) were characterized in detail using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis spectra. The 3D Fe 2 O 3 /TiO 2 /Si hierarchical photoanode exhibited a photocurrent density of 3.5 mA cm−2 at a bias potential of 1.23 V (vs. RHE), which is approximately 87.5 times higher than that of the Si nanowire array (NW) photoanode. The measurement results showed that the improved PEC performance could be attributed to the synergistic effect of the large surface area, low charge transfer resistance, and high charge separation in the hierarchical structure. Highlights • A novel 3D hierarchical Fe 2 O 3 /TiO 2 /Si photoanode was designed and fabricated. • The structural and morphological properties of Fe 2 O 3 /TiO 2 /Si were characterized. • The Fe 2 O 3 /TiO 2 /Si exhibited much higher photocurrent density than that of Si NWs. • EIS was conducted to investigate the properties of the charge transfer process. [ABSTRACT FROM AUTHOR]

In this paper, nanocrystalline antimony sulfide (Sb 2 S 3 ) thin films were prepared on a tin-doped indium oxide (ITO) substrate via a facile polyvinylpyrrolidone (PVP)-assisted hydrothermal method. The crystal structure, morphology and optical properties of the Sb 2 S 3 films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV–vis spectroscopy. Well-crystallized Sb 2 S 3 films possessed a honeycomb-like morphology with a whole thickness of approximately 360 nm on the ITO substrate and had a band gap of 2.0 eV. The reaction parameters that influenced the formation of Sb 2 S 3 films, such as reaction time, temperature and quantity of PVP were investigated. PVP was found to play an important role in the formation of the honeycomb-like Sb 2 S 3 films. In the absence of PVP, only large aggregates formed on the ITO substrate. A possible growth mechanism of the Sb 2 S 3 films has been proposed. Furthermore, the as-synthesized Sb 2 S 3 film exhibited a photocurrent density of −0.025 mA cm −2 at 0 V ( vs . RHE) in a neutral solution, close to that of the heated Sb 2 S 3 film. A stability test demonstrated that the as-synthesized Sb 2 S 3 film was stable in both neutral and acidic solutions. This investigation might provide a feasible method for preparing high-quality Sb 2 S 3 films to be used in solar energy conversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • The latest progress on intelligent development of UHPC are thoroughly reviewed. • The intelligent techniques are useful to aid the mixture design of UHPC. • The 3D printing technology creates the novel mode for the UHPC manufacturing. • Rheological properties are crucial for the 3D printed UHPC. The quick rise of intelligent technologies promotes the development of the construction industry into a new phase. As an advanced cement-based materials, ultra-high performance concrete (UHPC) breaks the performance upper limit of traditional concrete materials, which has also been empowered by intelligent techniques. Hence, this work comprehensively reviews the progress on the intelligent design and manufacturing of UHPC materials. The review mainly includes various design methods and performance characteristics of 3D printed UHPC (3DP-UHPC). The results reveal that currently, the particle packing methods, especially compressible packing model (CPM) and modified Andreasen and Andersen (MAA) model, are domain in designing UHPC materials. Meanwhile, the intelligent design methods, referring to optimal design by computer technology, are also increasingly used due to their high efficiency and accuracy in property predicting. Notably, recently, a new design concept was proposed by the joint use of particle packing models and machine learning techniques. On the other hand, the intelligent manufacturing of UHPC mainly refers to3DP-UHPC. Here, the rheology (especially thixotropy) and printability (pumpability, extrudability and buildability) are crucial for the manufacturing of 3DP-UHPC. Adding steel fibers can enhance the matrix strength, but also will increase the anisotropy of 3DP-UHPC by regulating fiber orientation. Overall, the intelligent development of UHPC is a significant direction for the construction industry, attracting increasing interest and attention. The outcomes of this study emphasize the advantages and significance of using intelligent techniques to design and manufacture UHPC materials, which holds great references and support for future construction projects. [ABSTRACT FROM AUTHOR]

• Micro/macro properties of LW/B-CC are investigated by experiments. • The mechanism of water migration is analyzed by molecular dynamics methodology. • Porous zeolite alleviates the self-desiccation of seawater-mixed LW/B-CC. • The migration of water molecules is more efficient in Na-heulandite. • Zeolite is an appropriate aggregate for producing LW/B-CC incorporating seawater. This study focus on dynamic characteristics of water distribution and migration in low water/binder cement-based composites (LW/B-CC) mixed with seawater and natural zeolite based on experimental and numerical approaches. More exactly, micro/macro properties of LW/B-CC are investigated by experiments and then the mechanism of water migration is analyzed by molecular dynamics methodology. The results reveal that the internal curing effects reflected by 1H nuclear magnetic resonance (NMR) and shrinkage test indicate that porous zeolite alleviates the self-desiccation of LW/B-CC matrix, especially in seawater-mixed LW/B-CC. Besides, the use of seawater improves the interfacial transition zone (ITZ) between zeolite and matrix. Molecular dynamics simulations exhibit an enriched ion content at the zeolite-water interface, which tends to block the transportation of water molecules. Meanwhile, the migration of water molecules is more efficient in Na-heulandite induced by a more equal distribution of extra-framework charges. With evidence from experimental and numerical approaches, ions in seawater are confined by the lattice of zeolite, and more water can be stored in the pores of zeolite and used as internal curing water; hence, zeolite is an appropriate type of aggregate for producing LW/B-CC incorporating seawater. [ABSTRACT FROM AUTHOR]

The structure of K 7 SrY 2 B 15 O 30 is clearly investigated and the fabricated WLED shows a low CCT and suitable CIE coordinates. [Display omitted] • A novel non-concentration quenching K 7 SrY 2 B 15 O 30 : Eu3+ phosphor was designed. • The PL properties and non-concentration quenching phenomena were explained. • Thermal quenching behavior and related mechanism were investigated in detail. • The phosphor has high quantum efficiency and excellent thermal stability. • The fabricated WLED showed low color temperature and suitable CIE color coordinate. Inhibiting energy migration between Eu3+ ions in a fixed host to get higher doping concentration is a permanent topic. Herein, a novel non-concentration quenching red-emitting K 7 SrY 2-2x B 15 O 30 : xEu3+ (0.1 ≤ x ≤ 1.0) phosphor was synthesized via high-temperature sintering method. XRD measurement, Rietveld refinement results, and radius percentage deviation calculation demonstrated the phase purity and the occupation preference of Eu3+ ions. With continuously increasing doping Eu3+ ions, the absence of concentration quenching could be explained by long distance between two Eu3+ (7.012 Å) and the K 7 SrEu 2 B 15 O 30 could exhibit striking photoluminescence performance with the highest emission wavelength centered at 617 nm. Meanwhile, under the radiation of 393 nm, the high internal quantum efficiency (∼ 78.71 %), excellent color purity (∼ 88.32 %) and robust thermal stability whose emission intensity at 140 °C could still reach ∼ 97.31 % could guarantee its potential application. When coating BaMgAl 10 O 17 : Eu2+, (Ba, Sr) 2 SiO 4 : Eu2+, and K 7 SrEu 2 B 15 O 30 on a near-ultraviolet chip, the bright white light with a low correlated color temperature of 4211 K and CIE color coordinates of (0.3675, 0.3556) could be obtained. Taking the analytic results above, the non-concentration quenching K 7 SrY 2 B 15 O 30 : Eu3+ compound has great potential to act as a candidate for red-emitting phosphors in solid-state lighting field. [ABSTRACT FROM AUTHOR]

In this study, aluminophosphate molecular sieve AlPO 4 -11, with one-dimensional elliptical channels, was investigated under high pressure in non-penetrating silicone oil by X-ray powder diffraction, infrared spectroscopy and theoretical simulation, focusing on its intrinsic and template-modified mechanical behaviors. Two distinct compressible regimes were observed for both the calcined and as-synthesized AlPO 4 -11 frameworks before pressure-induced amorphization (PIA). The channel cross-section in the calcined AlPO 4 -11 framework showed an obvious increase in the ellipticity during this process. The framework structure began to lose crystallinity at approximately 2–3 GPa and underwent significant amorphization at 6.6 GPa. PIA was mainly induced via the destruction of the constructed species along the periodic crystallographic planes which are parallel to the channel axis. The bulk moduli showed that this empty framework was rather soft in these regimes. For the as-synthesized AlPO 4 -11 framework, the mechanical stability of the channels was markedly improved by the template molecules. A different elliptic deformation of the cross-section with a reduced contractility in the minor axis direction was presented. Discontinuous volume evolution occurs at 3–4 GPa and significant amorphization was postponed to 13.7 GPa. The as-synthesized AlPO 4 -11 was stiffer than calcined AlPO 4 -11 and showed a soft to hard transformation due to the strengthened host-guest interaction upon compression. Moreover, infrared spectra indirectly confirmed the structural collapses by detecting the vibrational characteristics of the embedded template molecules. The present results provided a comparative and basic knowledge of the intrinsic and extrinsic stability, compressibility, channel deformation and collapse of the AlPO 4 -11 framework under high pressure. This study emphasized the importance of guest molecules in modifying the mechanical behaviors of zeolites and resisting framework collapse. • Both the calcined and as-synthesized AlPO 4 -11 frameworks exhibit isostructural transformations under high pressure. • Two different compressible regimes are found before pressure-induced amorphization. • The template molecules strengthen the mechanical stability and modify the structural evolution of AlPO 4 -11. • The template molecules also function as local probes to detect the framework transformations in the infrared experiment. [ABSTRACT FROM AUTHOR]

In this paper, CaIn 2 S 4 films with vertically aligned and interconnected hierarchical nanosheets were directly fabricated on tin-doped indium oxide (ITO) substrate via a facile hydrothermal process with no additional directing agent. The crystal structure, morphology and optical properties of the obtained CaIn 2 S 4 films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV–vis spectra. The results revealed the successful synthesis of uniform CaIn 2 S 4 hierarchical nanosheet films on ITO substrate with a whole thickness of about 3 μm and an average nanosheet thickness of about 20 nm, with the band gap of 2.17 eV. A possible mechanism for the formation of CaIn 2 S 4 films in hydrothermal process has been proposed. The CaIn 2 S 4 hierarchical nanosheet films exhibited a photocurrent density of approximate 0.2 mA cm−2 at 0.82 V (vs. NHE) in a neutral solution. In addition, the CaIn 2 S 4 films also exhibited superior photocatalytic activity for methyl orange and 1-naphthol. This study provided a green and facile method for the synthesis of high-quality CaIn 2 S 4 films applied in photocatalytic water splitting and photodegradation of organic pollutant. • Hierarchical nanosheet CaIn 2 S 4 films were fabricated by a hydrothermal process. • The CaIn 2 S 4 films exhibited good PEC performance in a neutral solution. • The CaIn 2 S 4 films demonstrated good MO and 1-naphthol degradation activity. • The structural and morphological properties of CaIn 2 S 4 films were characterized. [ABSTRACT FROM AUTHOR]

The dynamic behavior study of iodine molecules in the confinement environment is a fundamental scientific issue of great interest. Here, we report a comparative study on the high temperature transformation of iodine species in AFI and AEL channels. No solid, liquid and gas phase transition sequence is observed as the bulk iodine. In the AFI channels, the iodine chains dissociate into the lying iodine molecules and then transform to the standing iodine molecules upon heating. However, the iodine species in AEL channels show different behaviors. The iodine chains, lying and standing molecules still exist under the similar heating conditions. Furthermore, we discuss the discrepancies in terms of the total energy of the confinement systems when one iodine molecule is placed in the channel with different orientations and at different positions. The calculated energy shows the standing configuration is the stable state in I@AFI system, while the standing and lying iodine are preferable in I@AEL system. The higher translational energy barrier and different stable configurations for iodine molecules in AEL channels are responsible for the discrepancies in structural transformation from that in AFI channels. This study makes us have a good knowledge of the influence of host-guest interaction in the confinement environment on the dynamic behavior of confined iodine molecules and provides a method for further manipulating and controlling iodine molecules. Image 1 • The confined iodine molecules in the channels of AFI and AEL show different dynamic behaviors upon heating. • In the former, the confined iodine transform to standing configuration, while those in the latter exist in the states of chains, lying and standing iodine under similar heating conditions. • The confinement environments have an important influence on the molecular behavior of iodine. [ABSTRACT FROM AUTHOR]