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Pd25Cu75@SiO2 core–shell and PdCu@SiO2@Cu core–shell–satellite architectures were fabricated by silica-coating of Pd25Cu75 colloids in a reverse microemulsion. Hydrolysis of tetraethylorthosilicate in the reverse microemulsion containing hydrazine and ammonia yielded a core–shell structure, while the use of ammonia only, instead of a mixture of hydrazine and ammonia, formed a core–shell–satellite structure. The ammonia-leached copper species migrated onto the developing silica shell and formed smaller Cu clusters. Air-calcination at 673 K followed by H2-reduction at 773 K of the as-synthesized samples removed the organic surfactants and generated the permeable porous silica shells. The core–shell catalyst consisted of a metal core (8.5 nm) and a silica shell (7.8 nm), while the core–shell–satellite catalyst was composed by a metal core (7.0 nm), a silica shell (8.0 nm), and satellite Cu clusters (1.4 nm) on the silica shell. When used to catalyze the selective hydrogenation of acetylene to ethylene, the core–shell–satellite catalyst showed substantially enhanced activity and stability because of the synergetic catalysis between the metal core and the surrounding Cu clusters. [ABSTRACT FROM AUTHOR]

Surface ligands play an important role in shape‐controlled growth and stabilization of colloidal nanocrystals. Their quick removal tends to cause structural deformation and/or aggregation to the nanocrystals. Herein, we demonstrate that the surface ligand based on poly(vinylpyrrolidone) (PVP) can be slowly removed from Pd nanosheets (NSs, 0.93±0.17 nm in thickness) by simply aging the colloidal suspension. The aged Pd NSs show well‐preserved morphology, together with significantly enhanced stability toward both e‐beam irradiation and electrocatalysis (e.g. ethanol oxidation). It is revealed that the slow desorption of PVP during aging forces the re‐exposed Pd atoms to reorganize, facilitating the surface to transform from being nearly perfect to defect‐rich. The resultant Pd NSs with abundant defects no longer rely on surface ligand to stabilize the atomic arrangement and thus show excellent structural and electrochemical stability. This work provides a facile and effective method to maintain the integrity of colloidal nanocrystals by slowly removing the surface ligand. [ABSTRACT FROM AUTHOR]

Surface ligands play an important role in shape‐controlled growth and stabilization of colloidal nanocrystals. Their quick removal tends to cause structural deformation and/or aggregation to the nanocrystals. Herein, we demonstrate that the surface ligand based on poly(vinylpyrrolidone) (PVP) can be slowly removed from Pd nanosheets (NSs, 0.93±0.17 nm in thickness) by simply aging the colloidal suspension. The aged Pd NSs show well‐preserved morphology, together with significantly enhanced stability toward both e‐beam irradiation and electrocatalysis (e.g. ethanol oxidation). It is revealed that the slow desorption of PVP during aging forces the re‐exposed Pd atoms to reorganize, facilitating the surface to transform from being nearly perfect to defect‐rich. The resultant Pd NSs with abundant defects no longer rely on surface ligand to stabilize the atomic arrangement and thus show excellent structural and electrochemical stability. This work provides a facile and effective method to maintain the integrity of colloidal nanocrystals by slowly removing the surface ligand. [ABSTRACT FROM AUTHOR]

Monodisperse Au-Cu nanocubes and AuCu-Cu 1.96 S heterodimers were fabricated by a step-wise polyol reduction, simply through varying the Cu/Au atomic ratio and with the aid of oleylamine and 1-dodecanethiol as the capping agents. Au 0.5 Cu 0.5 nanocubes and AuCu-Cu 1.96 S heterodimers presented the improved performance for efficient catalysis in 4-nitrophenol reduction with NaBH 4 at 298 K due to the enriched surficial Cu atoms and electron transfer from Cu to Au via the formation of Au-Cu alloys. [Display omitted] Monodisperse gold-copper nanocubes and AuCu-cuprous sulfide (Cu 1.96 S) heterodimers were fabricated by a step-wise polyol reduction with the aid of oleylamine and 1-dodecanethiol. The geometric configuration was mediated by simply varying the Cu/Au atomic ratio: Au-Cu cubes with sizes of 6.4 and 4.3 nm were yielded at Cu/Au atomic ratios of 1/3 and 1/1, respectively; while AuCu-Cu 1.96 S heterodimer, consisting of a AuCu cube of 4.6 nm and a Cu 1.96 S sphere of 6.3 nm was obtained at Cu/Au atomic ratio of 3/1. Detailed structural analysis on the intermediate products, collected at different intervals during the synthesis, revealed that small-sized Au seeds formed at 423 K, followed by the growth of Cu and Cu 1.96 S crystals at 473 K. Oleylamine coordinated to Au3+ and Cu2+ and thus mediated the particle size; while 1-dodecanethiol bonded to Au3+ and directed the cubic morphology. Excessive Cu2+, at the Cu/Au atomic ratio of 3/1, interacted with 1-dodecanethiol and formed Cu 1.96 S spherical particle that epitaxially grew over the AuCu cube, resulting in a heterodimer structure. Due to the enriched surficial Cu atoms and their electronic interactions with Au atoms, Au-Cu nanocubes and AuCu-Cu 1.96 S heterodimers showed pronounced activities for the catalytic reduction of 4-nitrophenol to 4-aminophenol with NaBH 4 at 298 K. [ABSTRACT FROM AUTHOR]

Atomic layer deposition was applied to precisely disperse Pt on Sn‐, K‐modified Al2O3, while the dispersion of Pt depended strongly on the atmosphere. Pt presented as single‐atoms in oxidative atmosphere but both single‐atoms and clusters under reductive gas. After H2‐treatment at 873 K, Pt single‐atoms, clusters and particles co‐existed in the catalysts, but their population varied considerably. The typical nanoparticles featured by crystallized Pt3Sn alloys, while the subnanometric clusters contained amorphous Pt−Sn alloys in a monolayer geometry. When tested for propane dehydrogenation at 873 K, the monolayers displayed outstanding performance; the mass specific activity approached 5.1 molC3H6 molPt−1 s−1, which was 2.7 times greater than that of particles. Structural analysis revealed that the amorphous Pt−Sn monolayer exposed more surficial Pt atoms surrounded by Sn atoms, which finely tuned the electronic property of Pt and thus favored the activation of C−H bond in propane. [ABSTRACT FROM AUTHOR]

[Display omitted] • Structural evolution of CuPd single-particles depended on the reaction conditions. • H 2 -reduction at 873 K led to segregation of Pd atoms over Cu-enriched surface. • Pd atoms and electron-deficient Cu surface synergistically activated H 2 and CO 2. • O-containing species under CO 2 hydrogenation induced Cu migration to form clusters. Encapsulating metal nanoparticles into a porous silica shell, forming a core–shell geometry, has been popularly applied to prevent the particles from sintering at the elevated temperatures and under reactive gases. However, structure evolution of the metal particles under reaction conditions is less known. Here, the dynamic behavior of Cu 3 Pd single-particles, confined by a permeable silica shell, during CO 2 hydrogenation have been examined by microscopic and spectroscopic characterizations. It was found that H 2 -reduction of the bimetallic particle at 673 K led to the partial enrichment of Cu on the surface, while H 2 -treatment at 873 K resulted in the surface segregation of Pd owing to the stronger adsorption of H 2 on Pd. When subjected to CO 2 hydrogenation at 517–673 K, the enriched Pd surface atoms and the electron-deficient Cu atoms synergistically activated H 2 /CO 2 molecules and promoted the activity for the reverse water–gas shift. However, the Cu atoms partially migrated onto the SiO 2 shell and formed tiny Cu clusters, induced by the strong adsorption of O-containing reaction intermediates, forming a core@shell@satellite (CuPd@SiO 2 @Cu) architecture. [ABSTRACT FROM AUTHOR]

Boehmite (γ-AlOOH) nanorods and nanoplates were hydrothermally fabricated with the aid of tetrapropylammonium bromide (TPABr) by modifying the pH values of solutions. Under acidic conditions, the adsorption of anions such as Br− or NO3− on (001) and (100) surfaces may promote the heterogeneous nucleation of boehmite, leading to rod-like boehmite. While under basic solutions, the adsorption of TPA+ cation on the (010) surface inhibits the growth of boehmite along the [010] direction and generates nanosheets. The as-synthesized γ-AlOOH precursors were calcined at 873 K and transformed into γ-Al2O3 nanorods and nanosheets. The obtained γ-Al2O3 samples presented a clear morphology-depended effect for ethanol dehydration; nanorods gave the improved selectivity of C2H4 due to the exposure of {100} facets. [ABSTRACT FROM AUTHOR]

The size and shape of Pt nanoparticles largely determine the surface atom arrangements and the electronic properties. The control of particle size and shape heavily relies on the nucleation and growth rates of Pt crystals, which are intimately associated to the synthetic conditions. Here, Pt truncated octahedra and nanodendrites were fabricated by reducing Pt4+ cations in a methanol/water mixture using PVP as the capping agent, where the shape mediation of Pt particles was done by simply varying the methanol/water ratio. The structure evolution of the intermediate products during the synthesis was monitored by UV-Vis spectroscopy and TEM/STEM. It was found that methanol-rich solution induced fast reduction of Pt4+ cations and isotropic growth of Pt crystals into truncated octahedra, whereas water-rich solution led to a slow reduction of Pt species and continuous nucleation in the initial stage and fast autocatalytic growth and oriented attachment during the later stage, forming highly branched nanodendrites. [ABSTRACT FROM AUTHOR]

Endowed with flexible surface coordination and synergetic electronic status, bimetallic particles serve as promising heterogeneous catalysts as their microstructures evolved sensitively to the treatment atmospheres, whereas knowledge of dynamic manners is less. Herein, utilizing environmental transmission electron microscopy (ETEM), the reconstructions of Cu3Pd particles in oxidization/reduction atmospheres were explored at atomic scale. Specifically, bare Cu3Pd particles went through a phase separation of CuOx and PdOx during in situ oxidation, and subsequent agglomeration after H2 reduction. While protected in a silica shell, the confined Cu3Pd particles were oxidized into Cu1.5Pd0.5O2 phase after air calcination and subsequently restructured into versatile configurations during H2 reduction. Specifically, hollow Cu3Pd alloy architecture with Pd enriched layer near surface as reduced at 200 °C. Further rising 400 to 600 °C, it yielded disordered Cu3Pd alloys with slightly Pd atoms enrichment at outmost surface. The dynamical behaviors of single Cu1.5Pd0.5O2 particle during in situ reduction have been visualized in ETEM, wherein a series of deformation, elongation and rotation is involved during the hollow architecture firstly formation, and then vanished into a Cu3Pd solid solution nanoparticle. The tunable microstructures of Cu3Pd@SiO2 driven by redox atmospheres demonstrate efficient approach for precisely regulating the chemical environments of constrained bimetallic nanocatalysts. [ABSTRACT FROM AUTHOR]

Using a combination of plasmonic metal cores (Ag, Au, and Cu) and catalytic metal/semiconductor shells is a viable approach to enhance photocatalytic chemical reactions such as the oxygen evolution reaction (OER). However, the energy transfer mechanism between the plasmonic core and the catalytic shell as well as the functional mechanism of plasmon in the OER reactions is still unclear. Here, we designed core-shell Au@Ni3S2 and yolk-shell Au-Ni3S2 with well-controlled morphology. We directly mapped the distribution of plasmon using monochromatic low-loss electron energy loss spectroscopy. The structural pore in the yolk-shell Au-Ni3S2 greatly changes the dielectric environment and significantly enhances absorption of incoming light. The incoming photoenergy was dominantly dissipated on the shell by forming electron-hole pairs, leading to a higher energy flow rate for OER reactions. The catalytic activity of yolk-shell Au-Ni3S2 achieved nearly sixfold of core-shell Au@Ni3S2 and over 80-fold of pure Ni3S2 under illumination. Our results suggest that delicate microstructural control of catalysts can be used as an effective approach to design more efficient catalysts. [ABSTRACT FROM AUTHOR]

Mg 2 (Ge, Sn) solid solutions are eco-friendly thermoelectric materials in moderate temperature (500–800 K) range. However, p-type Mg 2 (Ge, Sn) solid solutions show poor thermoelectric performance compared to the n-type counterpart. In this work, the filtering of low energy holes and the blocking of thermal excited electrons in Mg 1.92 Li 0.08 Ge 0.4 Sn 0.6 by Si addition are demonstrated, which optimize the power factor by interface barrier and reduce the lattice thermal conductivity by nanoscale composition fluctuation. Finally, the power factor of ~1.85 × 10−3 Wm−1 K−2 and the dimensionless figure of merit ZT ~0.75 are achieved in Li doped Mg 2 Ge 0.4 Sn 0.6 with Si addition at 723 K. When the band gap of matrix (E g1) is smaller than the band gap of second phase (E g2), the interface barriers in panel (a) may filter the low-energy holes while allowing the high-energy holes in the valence band (VB) before bipolar effect. Above thermal excited temperature, the energy barriers in panel (b) can filter the low-energy holes and simultaneously block the thermal excited electrons in the conduction band (CB) to suppress bipolar effect. Eventually, the results indicate that the power factor obviously increased and the thermal conductivity significantly decreased by the filtering of the low-energy holes and the blocking of the thermal excited electrons. Unlabelled Image [ABSTRACT FROM AUTHOR]

Co9S8 has been regarded as a desirable anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity. However, lithium (Li) insertion caused large volume expansion, and subsequent pulverization and capacity decay are the major challenges for its practical applications in commercial LIBs. In this work, we design an Au@Co9S8 yolk-shell nanoparticle (NP) anode and use in-situ transmission electron microscopy to study the structural, morphological, and chemical evolutions in the NPs during lithiation. Our experimental results reveal that Li insertion leads to the volume expansion of the lithiated Co9S8 shell dominantly in the outward direction, and the conversion reaction between Li and Co9S8 induces the formation of a two-phase shell with metallic Co clusters dispersed in the as-formed Li2S matrix. With corroboration of chemo-mechanical simulations, we elucidate that the lithiation-generated comparative softer phase together with the inner stiffer unlithiated Co9S8 phase contributes to the outward only deformation pattern. In addition, the insulating nature of the as-formed Li2S results in an unexpected non-reactive Au yolk during lithiation. Our findings elucidate the significance of considering the dynamical phase transformations of active materials (i.e., Co9S8) for LIBs and provide valuable insights into the rational design of new generation high-performance LIBs. [ABSTRACT FROM AUTHOR]

Transparent oxide semiconductors hold great promise for many optoelectronic devices such as transparent electronics, UV-emitting devices, and photodetectors. A p-n heterojunction is the most ubiquitous building block to realize these devices. In this work, we report the fabrication and characterization of the interface properties of a transparent heterojunction consisting of p-type NiO and n-type perovskite BaSnO3. We show that high-quality NiO thin films can be epitaxially grown on BaSnO3 with sharp interfaces because of a small lattice mismatch (∼1.3%). The diode fabricated from this heterojunction exhibits rectifying behavior with a ratio of 500. X-ray photoelectron spectroscopy reveals a type II or “staggered” band alignment with valence and conduction band offsets of 1.44 eV and 1.86 eV, respectively. Moreover, a large upward band bending potential of 0.90 eV for BaSnO3 and a downward band bending potential of 0.15 eV for NiO were observed in the interface region. Such electronic properties have important implication for optoelectronic applications as the large built-in potential provides favorable energetics for photo-generated electron-hole separation/migration. [ABSTRACT FROM AUTHOR]

High-quality graphene was directly grown on the surface of Cu nanoparticles (NPs) via chemical vapor deposition (CVD) and then the graphene-covered Cu NPs were consolidated into dense Cu-graphene nanocomposites at different temperature. The surface of Cu NPs is well protected from oxidation due to the coverage of graphene. Nanocomposite consolidated at 650 °C (Cu/G-650) exhibits a hardness of 2.53 GPa with no distinctive different electrical resistivity compared with pure Cu, 2 orders of magnitude decrease in wear rate and 175% improvement in the coefficient of friction (COF) were reported for the Cu/G-650 nanocomposite as compared with pure Cu. The formation of graphene tribofilm is attributed for the effective protection of the Cu matrix from wear. [ABSTRACT FROM AUTHOR]

The evolution of the society is characterized by an increasing flow of information from things to the internet. Sensors have become the cornerstone of the internet-of-everything as they track various parameters in the society and send them to the cloud for analysis, forecast, or learning. With the many parameters to sense, sensors are becoming complex and difficult to manufacture. To reduce the complexity of manufacturing, one can instead create advanced functional materials that react to multiple stimuli. To this end, conducting polymer aerogels are promising materials as they combine elasticity and sensitivity to pressure and temperature. However, the challenge is to read independently pressure and temperature output signals without cross-talk. Here, a strategy to fully decouple temperature and pressure reading in a dual-parameter sensor based on thermoelectric polymer aerogels is demonstrated. It is found that aerogels made of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) can display properties of semiconductors lying at the transition between insulator and semimetal upon exposure to high boiling point polar solvents, such as dimethylsulfoxide (DMSO). Importantly, because of the temperature-independent charge transport observed for DMSO-treated PEDOT-based aerogel, a decoupled pressure and temperature sensing can be achieved without cross-talk in the dual-parameter sensor devices. [ABSTRACT FROM AUTHOR]

ABSTRACT Poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) has been reported as a successful functional material in a broad variety of applications. One of the most important advantages of PEDOT:PSS is its water-solubility, which enables simple and environmental friendly manufacturing processes. Unfortunately, this also implies that pristine PEDOT:PSS films are unsuitable for applications in aqueous environments. To reach stability in polar solvents, (3-glycidyloxypropyl)trimethoxysilane (GOPS) is typically used to cross-link PEDOT:PSS. Although this strategy is widely used, its mechanism and effect on PEDOT:PSS performance have not been articulated yet. Here, we present a broad study that provides a better understanding of the effect of GOPS on the electrical and electronic properties of PEDOT:PSS. We show that the GOPS reacts with the sulfonic acid group of the excess PSS, causing a change in the PEDOT:PSS film morphology, while the oxidation level of PEDOT remains unaffected. This is at the origin of the observed conductivity changes. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 814-820 [ABSTRACT FROM AUTHOR]

Size and phase-controlled growth and assembly of semiconductor nanostructures from ultrasmall building blocks are of great significance in aspects of both science and engineering. In this work, ZnS nanostructures including nanoparticles, nanobelts, single-crystal nanowires and layered ZnS(EN)0.5 hybrid structures are flexibly synthesized in a one-pot solvothermal system using ethylenediamine (EN) as the sole coordination agent. Comprehensive structure characterization, especially including spherical aberration corrected STEM imaging under an ultralow current density (2.55 A cm−2), provides direct evidence that the role of EN molecules varies from being surface stabilizers to being internal bridging blocks with changing introduction procedures. When introduced after the formation of ZnS precursors, EN passivates the non-polarized facets of ZnS clusters and activates the anisotropic growth along the [001] axis of the ZnS clusters into 1D wurtzite nanowires. When it is added before the formation of the ZnS clusters, EN molecules serve as the bridging blocks yielding layered ZnS(EN)0.5 hybrid structures through the connection of wurtzite ZnS (110) slabs. The layered ZnS(EN)0.5 nanostructures turn into single-crystal nanobelts after the removal of the EN components. [ABSTRACT FROM AUTHOR]

It is currently not understood how some chronic infections exhaust antigen-specific T cells over time and which pathogen components contribute to exhaustion. Here, we dissected the behavior of primed CD4+ T cells exposed to persistent antigen using an inducible transgenic mouse system that allowed us to control antigen presentation as the only experimental variable, independent of the persistent inflammation and disease progression that complicate infectious models. Moreover, this system restricted antigen presentation to dendritic cells (DC5) and avoided confounding B, CD8+ T, or innate cell responses. When antigen presentation was extended beyond the expansion phase, primed CD4+ls survived, but exhibited reduced memory functionality in terms of their proliferative capacity and cytokine expression potential., The effect was antigen dose and time dependent, not associated with increased PD-1 expression or reduced calcium influx, but impaired Jun phosphorylation in response to ICR engagement. Upon antigen removal, the cells regained the ability to proliferate, but remained unable to produce high levels of IL-2 and TNF-α. These data show that persistent antigen by itself rapidly induces a dysfunctional state in CD4+ T cells that is only partially reversible upon antigen removal. These findings have implications for vaccine optimization and for the possible reinvigoration of CD4+ T cells during chronic infection. [ABSTRACT FROM AUTHOR]

A Nile red (NR) dye cathode with an asymmetric redox structure of para C＝N and C＝O bonds was developed for use in an efficient lithium organic battery with a good capacity of 125 mA h g−1 and two visible discharge/charge voltage plateaus (≈2.0 V and ≈1.7 V). The NR cathode demonstrated the advantages of employing cost-effective dyes to achieve multigradient voltage platform regulation. [ABSTRACT FROM AUTHOR]

The strong metal-support interaction and its chemical nature was examined over a Ir/TiO2 catalyst, constructed by dispersing 2 nm Ir colloids on the {001} facets of anatase TiO2. Air-calcination of the Ir/TiO2 sample led to the oxidation of Ir particles into IrOx clusters. Upon H2-reduction at 573 K, the IrOx species were reduced into metallic with a prominent character for H2-chemisrption. As further raising the temperature to 673–773 K for H2-reduction, strong metal-support interactions occurred pronouncedly and the amounts of chemically adsorbed hydrogen dropped significantly. Spectroscopic and microscopic analysis found that the formation of surface Ir-Ti alloys on the Ir particles dominated the metal-support interactions, rather than the traditional encapsulation of the metal particles by TiOx overlayers. The surface Ir-Ti alloy, thus formed, promoted the selectivity for hydrogenating the C = O bond in acetophenone by altering the adsorption model of the C = O bond in the substrate. [ABSTRACT FROM AUTHOR]

In the field construction of shale oil (gas) hydraulic fracturing, the veins present in the shale may deflect the propagation path of hydraulic fractures. The metal chalcopyrite veins are widely contained in Jimusar Shale, but the effect of the metal veins on the fracture propagation at different temperatures is still unclear. Based on the extended finite element simulation and semicircular bending test method, the effect of temperature on the interaction law of the metal veins and hydraulic fractures is studied. The results show that the fracture propagation path in the rock sample is more tortuous with the increasing temperature; Compared with the 23 °C rock sample, the fracture toughness of rock samples without the vein and with the vein at 200 °C increase by 7.79% and 22.78%, respectively. The higher the temperature, the more difficult it is for the fracture to offset at the interface between the rock and the metal veins. But the temperature does not affect the distance of fractures offset. The results of this study can provide a reference for the design of hydraulic fractures of shale with the metal veins. • The shale samples with the metal vein are heated under the different temperature condition. • The interaction between the fracture and the metal vein is quantitatively investigated by the semicircular bending test, the acoustic emission test and wavelet analysis. • The results of the interaction between the metal vein and the fracture are investigated by the extended finite element method. • The effects of temperature on the interaction between the metal vein and the fracture are discussed. [ABSTRACT FROM AUTHOR]

The catalytic performance is tunable by controlling the reconstruction process in operando conditions. The surficial and interfacial properties of catalysts determine the catalytic activity of materials. • We tuned the catalytic performance of NiAu-based materials by the heat triggered the surficial and interfacial modification. • We promoted the activity stability of catalysts for hydrogen generation by controlled the reconstruction during reaction. • We used XPS and DFT to verify the synergistic effect between Au and Ni/NiO, in which they show high similarity. Catalytic activity of nanostructured materials are closely tied with structure, thus developing nanomaterials with processable structures has arisen as a new strategy for designing high active catalysts. In this work we report the realization of controllable structural evolution of NiAu-based materials in operando conditions. The structure evolution of NiAu catalysts at atomic scale has been characterized by ex-situ scanning transmission electron microscopy. The catalytic activity for ammonia borane hydrolysis has promoted for 4.4-fold after adapting structural evolution. The catalytic stability has increased for 16-fold of maintaining 75% activity. This work provides inspiration for emerging catalysts design based on bimetallic nanoparticles with both high performance and durability in a catalytic reaction system. [ABSTRACT FROM AUTHOR]

Wearable electronic devices have emerged as a pivotal technology in healthcare and artificial intelligence robots. Among the materials that are employed in wearable electronic devices, organic thermoelectric materials possess great application potential due to their advantages such as flexibility, easy processing ability, no working noise, being self-powered, applicable in a wide range of scenarios, etc. However, compared with classic conductive materials and inorganic thermoelectric materials, the research on organic thermoelectric materials is still insufficient. In order to improve our understanding of the potential of organic thermoelectric materials in wearable electronic devices, this paper reviews the types of organic thermoelectric materials and composites, their assembly strategies, and their potential applications in wearable electronic devices. This review aims to guide new researchers and offer strategic insights into wearable electronic device development. [ABSTRACT FROM AUTHOR]

Pressure (P), temperature (T), and humidity (H) are physical key parameters of great relevance for various applications such as in distributed diagnostics, robotics, electronic skins, functional clothing, and many other Internet‐of‐Things (IoT) solutions. Previous studies on monitoring and recording these three parameters have focused on the integration of three individual single‐parameter sensors into an electronic circuit, also comprising dedicated sense amplifiers, signal processing, and communication interfaces. To limit complexity in, e.g., multifunctional IoT systems, and thus reducing the manufacturing costs of such sensing/communication outposts, it is desirable to achieve one single‐sensor device that simultaneously or consecutively measures P–T–H without cross‐talks in the sensing functionality. Herein, a novel organic mixed ion–electron conducting aerogel is reported, which can sense P–T–H with minimal cross‐talk between the measured parameters. The exclusive read‐out of the three individual parameters is performed electronically in one single device configuration and is enabled by the use of a novel strategy that combines electronic and ionic Seebeck effect along with mixed ion–electron conduction in an elastic aerogel. The findings promise for multipurpose IoT technology with reduced complexity and production costs, features that are highly anticipated in distributed diagnostics, monitoring, safety, and security applications. [ABSTRACT FROM AUTHOR]

Conversion of CO2 gas to CO fuels is one of the most promising solutions for the increasing threat of global warming and energy crisis. The efficient catalyst Ni–Au dumbbell converting CO2 into CO at elevated temperatures has high CO product selectivity; however, the accompanied atomic diffusion and subsequent surface reconstruction affect the catalytic efficiency of chemical reaction. Atomic scale characterization of structural evolution of the catalyst, which is essential to correlate the functional mechanism to active catalyst surfaces, is yet to be studied. Here, in situ transmission electron microscopy experiments and atomistic simulations are performed to characterize the structural evolution of Ni–Au dumbbell nanoparticles under two different external stimuli. In the condition of high temperature and vacuum, the Ni–Au nanostructure reveals a clear shape reconstruction from the initial dumbbell to core–shell‐like, which is induced by capillary force to minimize free surface energy of the system. The shape transformation involves two stages of processes, initial fast Au diffusion followed by slow source‐controlled diffusion. At ambient temperature, the combination of CO2 and electron flux surprisingly induces analogous structural transformation of Ni–Au nanostructure, where the associated chemical reaction and CO absorption stimulate the Au migration on Ni surface. Such surface reconstruction can be widely present in catalytic reactions in different environmental conditions, and the results herein demonstrate the detailed processes of Ni–Au structure evolution, which provide important insights for understanding the catalyst performance. At high temperature or gas environment, the Ni‐Au nanostructure reconstructs from dumbell to core‐shell. Such surface reconstruction is widely present in catalytic applications, and the dynamical structural evolution provides important insights for understanding catalyst performance. [ABSTRACT FROM AUTHOR]

Perylene dianhydride (PDA), a low-cost, readily available, and chemically stable organic cathode material, has received extensive attention in recent years. However, its large π planar structure often results in poor or difficult-to-control micro-nanostructures during conventional electrode processing methods, such as dry mixing. This leads to limited cycling life and rate performance. Here, we present a simple electrospinning strategy for controlling the micro-nanostructures of electrodes based on PDA, carbon black Super P (SP), and polyvinylidene fluoride (PVDF) composites. The spinnable PVDF polymer not only provides the micro-nanofibrous structure but also realizes the function of the binder in the electrodes, offering the hierarchical micro-nanostructures of the electrospun PDA (PDA-es) electrodes. The unique structure enables PDA-es electrodes to possess rapid charge transport properties and ultrafast reaction kinetics. Specifically, the PDA electrode based on high molecular weight electrospun PVDF (PDA-es-H) demonstrates a high initial specific capacity (126.2 mA h g−1), robust cycling stability (∼95% and ∼60% capacity retention after 100 cycles at 50 mA h g−1 and 1000 cycles at 100 mA h g−1, respectively), and excellent rate performance. This study provides a straightforward and efficient strategy for realizing the micro-nanostructures of organic electrodes for high-performance lithium-organic batteries. [ABSTRACT FROM AUTHOR]

An in situ gel separator based on an electrospun three-layer nanofibrous membrane (PSE11-Gel) is developed for high-performance lithium-organic batteries (LOBs). The highly efficient shuttle effect inhibition of organic cathode molecules or lithiated intermediates has been demonstrated for PSE11-Gel to realize high-capacity stable LOBs. [ABSTRACT FROM AUTHOR]

Terahertz (THz) technologies provide opportunities ranging from calibration targets for satellites and telescopes to communication devices and biomedical imaging systems. A main component will be broadband THz absorbers with switchability. However, optically switchable materials in THz are scarce and their modulation is mostly available at narrow bandwidths. Realizing materials with large and broadband modulation in absorption or transmission forms a critical challenge. This study demonstrates that conducting polymer‐cellulose aerogels can provide modulation of broadband THz light with large modulation range from ≈ 13% to 91% absolute transmission, while maintaining specular reflection loss < −30 dB. The exceptional THz modulation is associated with the anomalous optical conductivity peak of conducting polymers, which enhances the absorption in its oxidized state. The study also demonstrates the possibility to reduce the surface hydrophilicity by simple chemical modifications, and shows that broadband absorption of the aerogels at optical frequencies enables de‐frosting by solar‐induced heating. These low‐cost, aqueous solution‐processable, sustainable, and bio‐friendly aerogels may find use in next‐generation intelligent THz devices. [ABSTRACT FROM AUTHOR]

Abstract Surface modification of nanostructured catalysts is fundamental in accelerating sluggish oxygen evolution reaction (OER). Herein we demonstrate that nanostructured Nickel Selenide (NiSe2) exhibits excellent capability for OER owing to the high compatibility between (200) plane and alkaline solution. The dendrite-like nickel selenide achieves a specific current density of 10 mA/cm2 at an overpotential low to ∼299 mV. The NiSe2 has high stability, in which overpotential decreased ∼2 mV after 10 000 cycles. We demonstrated that the catalytic efficiency of OER could be promoted by increasing the exposure ratio of (200) plane. This work discloses that kinetics of OER are related to specific facets exposure, in which it opens up the possibility of designing active and stable catalysts for OER utilization. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

In order to study the mechanism of gas generation from the asphaltene, the thermal pyrolysis simulation experiment of the asphaltene is carried out by using high temperature and high pressure closed system. During asphaltene pyrolysis, the amount of methane is constantly increased but those of ethane, propane, and butane + pentane are all first increased and then decreased and eventually go to zero with the increase of the experiment temperature. And the dynamic parameters of gaseous hydrocarbon generation can be used to analyze the dynamic procedure of the asphaltene pyrolysis at the geological scale. The experimental results can perfect the theory of the origin of natural gas and provide an evidence for source judgment and resource evaluation of natural gas in marine strata in China. [ABSTRACT FROM AUTHOR]

This study investigated the effects of free-range (FR) and cage-rearing (CR) systems on intestinal health, carcass traits, and microbial diversity in the Danzhou chicken breed. Two groups of 125 hens in each group, aged 42 wk, were reared under FR and CR systems. At 50 wk, 50 hens from each group were randomly selected for carcass analysis and 10 hens for intestinal morphology and microbiota profiling. Results indicated a significant increase in villus height (VH) in the duodenum (P < 0.05) , jejunum (P < 0.01), and ileum (P < 0.001) of the CR group. Additionally, the ratio of VH to crypt depth (VR) significantly (P < 0.001) increased in the jejunum, while crypt depth (CD) decreased significantly (P < 0.001) in the same section in the CR group. Carcass traits, including dress weight (DW), eviscerated with giblet weight (EGW), eviscerated weight (EW), and leg muscle weight (LW) significantly improved (P < 0.05) in the CR group. Microbial diversity showed significant β-diversity differences, with Lactobacillus, Enterococcus , and Oxalobacteraceae as dominant biomarkers in the CR group. Conversely, Actinomycetaceae, Erysipelotrichaceae, Coriobacteriaceae, Eubacterium, Actinomyces, Scardovia, and Lachnospiraceae were dominant in the FG group. Correlation analysis showed duodenum Lactobacillus was positively correlated with VH (P < 0.05) , EW (P < 0.05), and LW (P < 0.001). Jejunum Lactobacillus was positively correlated considerably with VH (P < 0.01), VR (P < 0.05) , DW (P < 0.05), EGW (P < 0.01), and LW (P < 0.001). Ileum Lactobacillus was positively correlated with EGW (P < 0.01), EW (P < 0.05), and LW (P < 0.01). Aeriscardovia in duodenum was positively (P < 0.01) associated with EGW. Enterococcus in the duodenum was positively (P < 0.05) associated with EGW and in Jejunum positively correlated with VH (P < 0.05) and VR (P < 0.01). The study concludes that cage rearing improves intestinal health, carcass traits, and microbial diversity in Danzhou chickens, with Lactobacillus and Enterococcus playing key roles. [ABSTRACT FROM AUTHOR]

Because of the booming industry, the leaked oily wastewater has seriously threatened human health and the ecological environment. To address this issue, we herein report a composite membrane for oil–water separation. Firstly, a silicone semi-interpenetrated network (IPN) was synthesized by the in situ polymerization of aminopropyl trimethoxysilane and vinyl trimethoxysilane in a polylactic acid (PLA) solution. Then, the PLA@silicone semi-IPN fibrous membranes were obtained via electrospinning the synthesized solution. The silicone semi-IPN offers adjustable inner morphologies and a good porous structure for fibrous membranes. Specifically, the PLA@silicone semi-IPN fibrous membrane shows an outstanding oil-absorbing value of 83.9 g/g and a good lipophilic/hydrophobic performance with a contact angle of 158.7°. More importantly, the obtained fibrous membrane owned a good oil–water selectivity. The oil droplets could be spread and absorbed by the fibrous membrane in water within 2.2 s. Such efficient separation for oil and water mixtures will make the PLA@silicone semi-IPN fibrous membrane a good candidate for oil-polluted water treatments. [ABSTRACT FROM AUTHOR]

For rotary machinery, periodic components in signals are always extracted to investigate the condition of each rotating part. Time domain averaging technique is a traditional method used to extract those periodic components. Originally, a phase reference signal is required to ensure all the averaged segments are with the same initial phase. In some cases, however, there is no phase reference; we have to establish some efficient algorithms to synchronize the segments before averaging. There are some algorithms available explaining how to perform time domain averaging without using phase reference signal. However, those algorithms cannot eliminate the phase error completely. Under this background, a new time domain averaging algorithm that has no phase error theoretically is proposed. The performance is improved by incorporating the fractional delay filter. The efficiency of the proposed algorithm is validated by some simulations. [Copyright &y& Elsevier]

• ZnO-Al 2 O 3 layer has a mesoporous structure and good affinity to H 2 S gas. • ZnO in layer can selectively adsorb and react with H 2 S gas molecules to form ZnS. • The formation of ZnS increases layer's elastic modulus and the sensing performance. • The SAW sensor can detect 10 ppb H 2 S gas with a response of 500 Hz. ZnO-Al 2 O 3 nanocomposite was synthesized and developed as a high performance sensitive and selective layer for surface acoustic wave (SAW) sensor, aiming for in-situ detection of H 2 S gas in ppb level operated at room temperature. ZnO-Al 2 O 3 nanocomposite, synthesized though a sol-gel method, was spin-coated onto a quartz based SAW resonator. This composite layer inherits the mesoporous structure of the Al 2 O 3 layer and good affinity to H 2 S gas molecules of the ZnO layer, and thus can selectively adsorb and react with H 2 S gas molecules to form ZnS compounds on its surface. This reaction leads to significant decreases of both pore sizes and total pore volume of the layer, an increase of layer's elastic modulus, thus causing a large positive shift of the frequency responses of the SAW sensor. The sensor operated at room temperature shows a frequency response of ∼500 Hz to 10 ppb H 2 S, with an excellent selectivity and good recovery property. [ABSTRACT FROM AUTHOR]

• The surfactant- and polymer-free synthesis of a new kind of nonmetallic N-doped Pt nanoparticles. • The N doping within Pt lattice induces tensile strain, leading to an enhanced ORR activity and excellent durability. • This N-doped Pt nanocatalyst shows a negligible degradation in ORR activity (only 3.7%) after a 20,000-cycle ADT. • Provide a competitive strategy for preparation of Pt-based oxygen reduction catalysts in PEMFCs. The availability of highly active and durable Pt based catalysts at a high metal loading is a prerequisite for practical applications in proton exchange membrane fuel cells (PEMFCs). Herein, we for the first time report the simple surfactant- and polymer-free synthesis of nonmetallic N doped Pt nanoparticles as electrocatalysts with an enhanced activity and excellent durability for oxygen reduction reaction (ORR) and such a synthetic procedure has been extended in a large-scale (>100 g/batch) for practical production already. X-ray diffraction and aberration-corrected transmission electron microscopy results clearly confirm that the doping of N within Pt lattice leads to the tensile strain in Pt nanoparticles. The tensile-strained Pt nanoparticles exhibit a negligible ORR activity decay by only 3.7% after a 20,000-cycle accelerated durability test (ADT) between 0.6 and 1.1 V/RHE, which places it among the most durable Pt-based catalysts reported for the ORR. While eliminating the strain effect, the activity degradation of the ORR on the Pt nanoparticles increases to 18.1%, close to that of commercial Pt/C catalyst (27.9%). Importantly, the tensile strain of N doped Pt nanoparticles is still remained after the ADT, assessing the structural stability of N-doped Pt nanoparticles. Theoretical calculations reveal that the N-doped Pt nanoparticles are chemically more stable than pristine ones due to Pt-N bonding effect, thus explaining well its excellent durability during the ORR. PEMFC integrated with as-prepared catalyst delivers a cell voltage of 0.65 V at the current density of 1.4 A·cm−2, satisfying the needs for vehicle use. The simple surfactant- and polymer-free approach presented here can be readily applied to other nonmetal doped Pt nanostructures and provides a promising potential for the practical applications in PEMFCs. [ABSTRACT FROM AUTHOR]

CuCo 2 S 4 is regarded as a promising electrode material for supercapacitor, but has inferior conductivity and poor cyclic stability which restrict its wide-range applications. In this work, hierarchically hybrid composite of CuCo 2 S 4 /carbon nanotubes (CNTs) was synthesized using a facile hydrothermal and sulfuration process. The embedded CNTs in the CuCo 2 S 4 matrix provided numerous effective paths for electron transfer and ion diffusion, and thus promoted the faradaic reactions of the CuCo 2 S 4 electrode in the energy storage processes. The CuCo 2 S 4 /CNTs-3.2% electrode exhibited a significantly increased specific capacitance of 557.5 F g−1 compared with those of the pristine CuCo 2 S 4 electrode (373.4 F g−1) and CuO/Co 3 O 4 /CNTs-3.2% electrode (356.5 F g−1) at a current density of 1 A g−1. An asymmetric supercapacitor (ASC) was assembled using the CuCo 2 S 4 /CNTs-3.2% as the positive electrode and the active carbon as the negative electrode, which exhibited an energy density of 23.2 Wh kg−1 at a power density of 402.7 W kg−1. Moreover, the residual specific capacitance of this ASC device retained 85.7% of its original value after tested for 10,000 cycles, indicating its excellent cycle stability. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ar ion implantation modifies the surface of fused silica and improves the LIDTs of the optics at moderate fluences. • The generation of compressive stress layer strengthens the surface of fused silica by surface densification. • The surface molecular structure of fused silica changes during the Ar ion implantation process. • The concentration of defects at fused silica surface reduces when the ion fluence is below 1 × 1017 ions/cm2. Abstract In this work, effects of 10 keV argon ion implantation on laser-induced damage threshold (LIDT) of fused silica were systematically investigated with ion fluences ranged from 1 × 1016 ions/cm2 to 1 × 1018 ions/cm2. Results show that only when the ion fluence increases above 1 × 1017 ions/cm2, the surface roughness apparently increases due to the formation of argon bubbles in the surface of fused silica. The concentration of defects decreases with the increased fluences up to 1 × 1017 ions/cm2 but then increases further, especially for the oxygen deficient center (ODC) defect. Based on the nanoindentation test results, Ar ion implantation generates large compressive stress and strengthens the surface of fused silica by surface densification. With the increase of the Ar ion fluences, the LIDTs of the samples increase due to the increases in both surface compressive stress and defects annihilation. However, at higher ion fluences, the increase of the densities of defects and argon bubbles are identified as the key reasons for the decrease of the LIDTs. Therefore, Ar ion implantation can improve the LIDTs of fused silica at moderate fluences. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pt 3 Fe particle is individually confined by SiO 2 forming the Pt 3 Fe@SiO 2 core–shell nanostructure. • The crystal-phase of a single Pt 3 Fe particle is tuned from the disordered A1 to the ordered L1 2. • L1 2 phase exhibits the superior behaviors than A1 phase for C 2 H 2 hydrogenation toward C 2 H 4. • Pt 3 ensemble with isolated 3-fold hollow site is enriched on L1 2 particle. Tuning the crystal-phase of bimetallic particles enables a precise control of catalytically active sites but is experimentally challenged by the averaging ensemble effects that are caused by the particle communications occurred during the crystal-phase transformation. Here, H 2 -treatment at 773–973 K of Pt 3 Fe single-nanoparticle, confined by a permeable silica shell, achieved crystal-phase transformation from the disordered A1 phase to the chemically ordered L1 2 phase. Detailed microscopic and spectroscopic characterizations have identified that the disordered A1 particle possessed contiguously connected large Pt domains while the ordered L1 2 particle afforded regularly populated Pt 3 ensembles surrounded by Fe single-atoms. The isolated 3-fold hollow Pt site in the three-atom ensemble efficiently boosted the adsorption of acetylene, yielding a much higher hydrogenation activity. The reaction rate of the L1 2 particle was twice of that for the A1 particle. Moreover, the charge transfer from the neighboring Fe single-atoms to the Pt atoms on the L1 2 particle expedited the desorption of ethylene, promoting the selectivity as well. Overall, both geometric and electronic interactions in the ordered crystal-phase synergistically facilitated the selective hydrogenation of acetylene to ethylene. [ABSTRACT FROM AUTHOR]

Zr-based ceramics are of interest for applications in aerospace propulsion, owing to their high hardness and stability. Application of these ceramics requires better understanding of their mechanical behavior in small scales and at elevated temperatures. Here, we prepared a ZrB 2 -ZrC ceramic eutectic composite, consisting of self-assembled ZrC rods grown within a single-crystalline ZrB 2 matrix, and studied the mechanical properties of the individual eutectic phases using nanoindentation at both room and elevated-temperatures. The Vickers hardness of the eutectic composite was measured at room temperature. These data provide insight into the understanding of the mechanical behavior of the individual phases of non-oxide ceramic eutectic composites for high-temperature applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel polyimide-based nanofiltration membranes were prepared by constructing dual coordination interactions. • The skin and supporting layers of NF membranes can be controlled by designing coordination interactions. • Nanofiltration membrane performance optimized by controllable microstructure. Polyimide-based nanofiltration membranes (NF) featuring customizable chemical structure and outstanding comprehensive performance have garnered tremendous interest for potential applications in ions rejection. Coordinated interactions can build supramolecular networks in polyimide that reshuffle phase separation behavior during membrane formation, thus conferring microstructural flexibility to nanofiltration membranes. In this paper, novel nanofiltration membranes were prepared by constructing dual coordination interactions in polyimide, and the structures were confirmed by NMR, FTIR, EDX, and XPS analyses. As expected, the skin and supporting layers of the PI-based NF membranes can be controlled by designing coordination conditions during membrane formation. A promising result is that the resulted NF membranes occur higher reject of metal ions than the pristine membranes prepared by conventional non-solvent induced phase separation methods. The optimized performance showed significantly higher permeability for removing Mg2+ ions, giving water permeance of 477.7 L m−2 h−1·bar−1 and a rejection of over 80%. Moreover, the resulted PI-based NF membranes occur better solvent resistance than the pristine NF membranes due to the enhanced coordination structures. As a preliminary study, this work gives a new strategy to regulate the microstructure of nanofiltration membranes, promising further potential for applications in ion removal. [ABSTRACT FROM AUTHOR]

Single crystal silicon is an important material used for semiconductor devices and also a potential material in device research. Far-infrared optical properties are studied for the helium ion implanted samples with different fluences of 5.0 × 1016, 1.0 × 1017, 2.0 × 1017, and 4.0 × 1017 cm−2. The absorption coefficient and refractive index of silicon with different helium concentrations are measured in the wave number range from 4 to 85 cm−1 and temperature range from 145 to 520 K. The results show that the absorption coefficient increases with increasing fluence of helium ions, but the refractive index decreases. The correlations between absorption coefficient and refractive index and temperature of all samples are similar. The refractive index increases with temperature in the whole measurement temperature range, but the absorption coefficient has different trends in the different wavebands. The absorption coefficient decreases with the increase of temperature in the region below 12 cm−1; however, the absorption coefficient increases when the wave number is larger than 30 cm−1. The absorption coefficient curves at different wavebands are well fitted by the Drude model. A large number of helium bubbles and defects, such as voids and dislocations have been observed in the implanted area by transmission electron microscopy (TEM), which contributes to the increase of optical absorption. [ABSTRACT FROM AUTHOR]

Multi-fracture hydraulic fracturing has been widely used in unconventional oil or gas production. Determining the fracture geometry at the end of multi-fracture propagating simultaneously and early estimating of the stimulation performance can improve the understanding of the well productivity. Coupled with other information on treatment execution, this understanding may help define changes in treatment design and execution that increase well productivity. G-function pressure drop curves analysis is an important method to determine the single fracture geometry. However, it is difficult to estimate the multi-fracture geometry in each fracturing stage by G-function model. In this paper, we propose a new model to calculate the multi-fracture geometry based on the G-function plot of pressure falloff data after hydraulic-fracture treatment in each fracturing stage. First, stress shadow and the dynamic partitioning of flow rate are first considered in the G-function model for the calculation of multi-fracture geometry distribution. Second, proportional function of fracture length is incorporated in the G-function model in this paper, which solves the problem of the non-uniqueness of fracture lengths and widths calculation outcomes. Through comparing with the numerical simulation results, our model is verified. Finally, a sensitivity analysis of the fracture control parameters is performed based on our model. This paper provides a new semi-analytical method to quickly determine the multi-fracture geometry after each horizontal well fracturing stage. It can be used to evaluate the performance of multi-fracture hydraulic fracturing and help improve the well productivity. • A field-scale model was proposed to determine multi-fracture geometry by hydraulic-fracture treatment pressure falloff data. • Stress shadow and partitioning of flow rate were considered in the G-function model for calculating multi-fracture geometry. • Effects of physical parameters (N , σ min , n ′ , d , and H) related to multi-fracture characteristics were analyzed. [ABSTRACT FROM AUTHOR]

Developing fully rigid-chain polyimides with reversible sol-gel/gel-sol transitions is of great interest for designing high-performance materials. To date, few approaches have been employed to construct polyimide gels other than hydrogen bonding. Here, we report a polyimide-Zn(II) complex with thermo-responsive sol-gel/gel-sol transition behavior by introducing supramolecular coordination interactions. The tunable dynamic sol-gel behaviors of polyimide-Zn(II) complexes were confirmed using rheological methods. Microstructure analysis shows that coordination interactions occur between the benzimidazole molecules and Zn(II) ions. As a result, the apparent viscosity of the polyimide-Zn(II) complex even rises approximately four orders of magnitude higher than that of the PI-neat oligomer solution. Based on the 2D-correlation spectra and X-ray diffraction results, we deduced that the formation of dense chain stacking caused by coordination effects plays an essential part in the reversible sol-gel transition. As a preliminary experiment, this work gives a novel strategy to construct polyimide gels, showing application prospects in the fabrication of porous polyimide membranes, high-performance polyimide fibers, and aerogels, etc. • A novel polyimide-Zn(II) organogel was prepared by introducing supramolecular coordination bonds. • Strong interactions undergo between the benzimidazole molecules and Zn(II) ions. • The chain stacking behavior caused by coordination effects plays an essential part in the reversible sol-gel transition. [ABSTRACT FROM AUTHOR]

Photocatalytic overall water and CO2 conversion splitting under visible light irradiation. • Synthesis of phosphorus doped g-C3N4 (P-CN) with its coupling to CdSe quantum dots (QDs). • For band gap engineering conformation DFT and Time depended-DFT were used. • Expending visible-light response of g-C3N4 upto near infra-red region (700 nm). • Photocatalytic Activities for solar fuel production and environmental remediation. Solar energy harvesting and conversion into useful chemical energy with the aid of semiconductor photocatalysts is a promising technique to solve both energy and environmental issues. This work reports a successful synthesis of CdSe quantum dots (QDs) modified phosphorus doped g-C 3 N 4 (P-CN) for advanced photocatalytic applications. Phosphorus doping and structural coupling with CdSe QDs are shown to significantly extend visible-light response of g-C 3 N 4 up to 700 nm. The optimized sample 4CdSe/P-CN demonstrates enhanced visible-light driven overall water splitting activities for H 2 and O 2 evolution i.e. 113 and 55.5 μmol.h−1. g−1, respectively, as well as very high photocatalytic CO 2 to CH 4 conversion efficiency (47 μmol.h−1. g−1). It also exhibit higher activity (78 %) for 2,4-dichlorophenol degradation as compared to pristine CN-sample. Combined photoluminescence, transient/single wavelength photocurrent, photoelectrochemical, and coumarin fluorescence spectroscopy demonstrate that 4CdSe/P-CN nanocomposite exhibit enhanced charge separation efficiency which is responsible for improved visible light catalytic activities. Our work thus provide a new strategy to design low-cost and sustainable photocatalysis with wide visible-light activity for practical overall water splitting and CO 2 reduction applications. [ABSTRACT FROM AUTHOR]

Mild aqueous rechargeable Zn-ion batteries emerge as potential grid energy storage devices due to excellent cycling stability, high Coulombic efficiency and low cost. However, reliable cathodes with high rate capability still need to be optimized. Previous vanadium oxide cathodes generally show the mechanism of Zn2+ intercalation into crystal layers, during which the lattice structure of active materials keeps stable. Different from this intercalation mechanism, here, we report a special conversion mechanism of Zn2+ storage. Vanadium oxide nanotubes with interlaminar dodecylamine are employed as the cathode. During the initial activation process, the cathode is fully converted to layered zinc pyrovanadate with amorphous zones induced by protonated dodecylamine, while the discharge process results in reversible formation of an amorphous-phase product during cycling. Layered zinc pyrovanadate can be electrochemically recovered from the amorphous phase after the Zn2+ de-intercalation. Despite an armorphous phase as the discharge product, this active material shows high cycling stability and fast Zn2+ kinetics. In addition, this cathode displays a specific energy density of ~242.5 Wh kg−1 and shows capacity retention of 80.5% after 950 cycles at 2.4 A g−1. Even at a high current density of 9.6 A g−1, the cathode delivers a specific energy of ~50 Wh kg−1 (5460 W kg−1) in 33 s. Although vanadium oxide nanotubes with interlaminar dodecylamine ions show little success in Li/Na-ion batteries with non-aqueous electrolytes, a mild aqueous Zn-ion system rejuvenates this material. • A special Zn2+ storage mechanism of layered vanadium oxide is reported. • This mechanism is different from general interlayer intercalation. • The cathode would reversibly convert into an amorphous phase. • The cathode shows remarkable cycling performance and fast Zn2+ kinetics. • A mild aqueous Zn-ion system rejuvenates vanadium oxide nanotubes. [ABSTRACT FROM AUTHOR]

Temporary plugging and diverting fracturing (TPDF) technique has been widely used in exploiting hydrocarbon resources in conventional/unconventional formations. The key to ensuring the success of this technique lies in the efficient plugging of the previously created fractures. However, the plugging characteristics of diversion agents influenced by the fracture geometry have not been efficiently investigated through experiments. In this study, the conventional true tri-axial hydraulic fracturing system was modified, then a series of investigative experiments were carried out and a novel experimental method was proposed to systematically investigate the plugging characteristics of diversion agents within the fracture. This method can not only investigate the effects of fracture geometry on the diversion agent distribution, plugging capacity, and plugging speed within fracture, but also optimize the diversion agent recipe for plugging various geometries fracture with different apertures, thus saving the dosage of diversion agents and fracturing fluids. Moreover, under certain conditions, as for the common four types of fractures i.e., distorted (type-Ⅰ) fracture, inclined and flat (type-Ⅱ) fracture, longitudinal and flat (type-Ⅲ) fracture, and transverse and flat (type-Ⅳ) fracture, the required ratio of diversion agent dosage for plugging is approximately 1:7:15:3. • The common tri-axial hydraulic fracturing system was modified for carrying out diverting fracturing experiments. • A novel experimental method was proposed to investigate the plugging characteristics of diversion agents within fracture. • The influences of fracture geometry on the plugging characteristics of diversion agents were systematically investigated. • Reliable guidelines were presented to improve the success rate of temporary plugging and diverting fracturing. [ABSTRACT FROM AUTHOR]