Solid-Liquid Interfacial Engineered Large-Area Two-Dimensional Covalent Organic Framework Films.

Constructing uniform covalent organic framework (COF) film on substrates for electronic devices is highly desirable. Here, a simple and mild strategy is developed to prepare them by polymerization on a solid-liquid interface. The universality of the method is confirmed by the successful preparation of five COF films with different microstructures. These films have large lateral size, controllable thickness, and high crystalline quality. And COF patterns can also be directly achieved on substrates via hydrophilic and hydrophobic interface engineering, which is in favor of preparing device array. For application studies, the PyTTA-TPA (PyTTA: 4,4',4'',4'''-(1,3,6,8-Tetrakis(4-aminophenyl)pyrene and TPA: terephthalaldehyde) COF film has a high photoresponsivity of 59.79 µA W-1 at 420 nm for photoelectrochemical (PEC) detection. When employed as an active material for optoelectronic synaptic devices for the first attempt, it shows excellent light-stimulated synaptic plasticity properties such as short-term plasticity (STP), long-term plasticity (LTP), and the conversion of STP to LTP, which can be used to simulate biological synaptic functions.

Molecular Design of Multifunctional Integrated Polymer Semiconductors with Intrinsic Stretchability, High Mobility, and Intense Luminescence.

Multifunctional semiconductors integrating unique optical, electrical, mechanical, and chemical characteristics are critical to advanced and emerging manufacturing technologies. However, due to the trade-off challenges in design principles, fabrication difficulty, defects in existing materials, etc., realizing multiple functions through multistage manufacturing is quite taxing. Here, an effective molecular design strategy is established to prepare a class of multifunctional integrated polymer semiconductors. The pyridal[1,2,3]triazole-thiophene co-structured tetrapolymers with full-backbone coplanarity and considerable inter/intramolecular noncovalent interactions facilitate short-range order and excellent (re)organization capability of polymer chains, providing stress-dissipation sites in the film state. The regioregular multicomponent conjugated backbones contribute to dense packing, excellent crystallinity, high crack onset strain over 100%, efficient carrier transport with mobilities exceeding 1 cm2  V-1  s-1 , and controllable near-infrared luminescence. Furthermore, a homologous blending strategy is proposed to further enhance the color-tunable luminescent properties of polymers while effectively retaining mechanical and electrical properties. The blended system exhibits excellent field-effect mobility (µ) and quantum yield (Φ), reaching a record Φ · µ of 0.43 cm2  V-1  s-1 . Overall, the proposed strategy facilitates a rational design of regioregular semicrystalline intrinsically stretchable polymers with high mobility and color-tunable intense luminescence, providing unique possibilities for the development of multifunctional integrated semiconductors in organic optoelectronics.

Dual-Specificity Inhibitor Targets Enzymes of the Trehalose Biosynthesis Pathway.

To reduce the risk of resistance development, a novel fungicide with dual specificity is demanded. Trehalose is absent in animals, and its synthases, trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP), are safe fungicide targets. Here, we report the discovery of a dual-specificity inhibitor of MoTps1 (Magnaporthe oryzae Tps1, TPS) and MoTps2 (M. oryzae Tps2, TPP). The inhibitor, named A1-4, was obtained from a virtual screening and subsequent surface plasmon resonance screening. In in vitro assays, A1-4 interacts with MoTps1 and MoTps2-TPP (MoTps2 TPP domain) and inhibits their enzyme activities. In biological activity assays, A1-4 not only inhibits the virulence of M. oryzae on host but also causes aggregation of conidia cytosol, which is a characteristic phenotype of MoTps2. Furthermore, hydrogen/deuterium exchange mass spectrometry assays support the notion that A1-4 binds to the substrate pockets of TPS and TPP. Collectively, A1-4 is a promising hit compound for the development of safe fungicide with dual-target specificity.

Topology-Selective Manipulation of Two-Dimensional Covalent Organic Frameworks.

The manipulation of topological architectures in two-dimensional (2D) covalent organic framework (COF) materials for different applications is promising but remains a great challenge. Here, we first report the topology-selective synthesis of two distinct varieties of 2DCOFs, imine-based HT-COFs and benzimidazole-fused BI-HT-COFs, by simply altering acid catalysts. To HT-COFs, a superlattice of 1D channel with a persistent triangular shape is formed via Schiff base reaction, while to BI-HT-COFs, a hexagonal lattice structure with a highly conjugated structure and imidazole linkages is constructed due to an imine-based cyclization reaction. The two COFs exhibited marked differences in their bandgap, chemical stability, molecular adsorption, and catalytic activity, which make them have different fields of application. This work not only diversifies the hexaaminotriphenylene-based 2DCOF topologies but also provides vivid examples of structure-property relationships, which would facilitate fundamental research and potential applications of 2DCOFs.

CO Binding Energy is an Incomplete Descriptor of Cu-Based Catalysts for the Electrochemical CO2 Reduction Reaction.

CO binding energy has been employed as a descriptor in the catalyst design for the electrochemical CO2 reduction reactions (CO2 RR). The reliability of the descriptor has yet been experimentally verified due to the lack of suitable methods to determine CO binding energies. In this work, we determined the standard CO adsorption enthalpies ( Δ H C O ∘ ${\Delta {H}_{CO}^{^\circ{}}}$ ) of undoped and doped oxide-derived Cu (OD-Cu) samples, and for the first time established the correlation of Δ H C O ∘ ${\Delta {H}_{CO}^{^\circ{}}}$ with the Faradaic efficiencies (FE) for C2+ products. A clear volcano shaped dependence of the FE for C2+ products on Δ H C O ∘ ${\Delta {H}_{CO}^{^\circ{}}}$ is observed on OD-Cu catalysts prepared with the same hydrothermal durations, however, the trend becomes less clear when all catalysts investigated are taken into account. The relative abundance of Cu sites active for the CO2 -to-CO conversion and the further reduction of CO is identified as another key descriptor.

Boosting CO2 Photoreduction via Regulating Charge Transfer Ability in a One-Dimensional Covalent Organic Framework.

Two-dimensional (2D) imine-based covalent organic frameworks (COFs) hold potential for photocatalytic CO2 reduction. However, high energy barrier of imine linkage impede the in-plane photoelectron transfer process, resulting in inadequate efficiency of CO2 photoreduction. Herein, we present a dimensionality induced local electronic modulation strategy through the construction of one-dimensional (1D) pyrene-based covalent organic frameworks (PyTTA-COF). The dual-chain-like edge architectures of 1D PyTTA-COF enable the stabilization of aromatic backbones, thus reducing energy loss during exciton dissociation and thermal relaxation, which provides energetic photoelectron to traverse the energy barrier of imine linkages. As a result, the 1D PyTTA-COF exhibits significantly enhanced CO2 photoreduction activity under visible-light irradiation when coordinated with metal cobalt ion, yielding a remarkable CO evolution of 1003 µmol g-1 over an 8-hour period, which surpasses that of the corresponding 2D counterpart by a factor of 59. These findings present a valuable approach to address in-plane charge transfer limitations in imine-based COFs.

Development of an exogenous coreactant-free electrochemiluminescent sensor for sensing glucose.

Covalent organic frameworks (COFs) are crystalline porous polymers with the characteristics of a large specific surface area, controllable pore structures, high stability, and low mass density. Herein, we demonstrate the development of an exogenous coreactant-free electrochemiluminescent sensor based on a hydrazone-linked COF for sensing glucose. We synthesized a TFPPy-DMeTHz-COF with the hydrazone bond as the linkage and 2,5-dimethoxyterephthalohydrazide (DMeTHz) and 1,3,6,8-tetrakis(4-formylphenyl)pyrene (TFPPy) as the monomers. The obtained TFPPy-DMeTHz-COF exhibits high electrochemiluminescence (ECL) efficiency (21.7%) without either the addition of any coreactants or the removal of dissolved O2, and the ECL signal intensity of the TFPPy-DMeTHz-COF is 6.6 and 113-fold higher than those of TFPPy and DMeTHz, respectively. The enhanced ECL emission of the TFPPy-DMeTHz-COF is induced by OH- in PBS, and the ECL signal exhibits linear dependence on the pH value in the range from 3 to 10. When glucose is present, the addition of glucose oxidase (GOx) to the O2-containing solution generates gluconic acid, and the resultant gluconic acid can induce the decrease of the pH value and the quenching of the ECL emission of the TFPPy-DMeTHz-COF. This exogenous coreactant-free electrochemiluminescent sensor exhibits good selectivity, excellent stability, and high sensitivity with a limit of detection (LOD) of 0.031 µM, and it can accurately detect glucose in human serum.

Recrystallization of 2D C-MOF Films for High-Performance Electrochemical Sensors.

Two-dimensional (2D) conjugated metal-organic framework (c-MOF) films bring a completely new opportunity in the fields of catalysis, energy, and sensors, but preparing large-area continuous 2D c-MOF films remains a tremendous challenge. Here, we report a universal recrystallization strategy to synthesize large-area continuous 2D c-MOF films, revealing that the recrystallization strategy can significantly improve the electrochemical sensor sensitivity. Applying the 2D Cu3(HHTP)2 (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) c-MOF film as the active layer, the electrochemical sensor for glucose detection shows a high sensitivity of 20600 µA mM-1 cm-2, which is the best compared with the active materials reported previously. Most importantly, the as-made Cu3(HHTP)2 c-MOF-based electrochemical sensor possesses excellent stability. Overall, this work brings a brand-new universal strategy to prepare large-area continuous 2D c-MOF films for electrochemical sensors.

Sandwiched Polymer Nanocomposites Reinforced by Two-Dimensional Interface Nanocoating for Ultrahigh Energy Storage Performance at Elevated Temperatures.

Polymer-based dielectrics are essential components in electrical and power electronic systems for high power density storage and conversion. A mounting challenge for polymer dielectrics is how to maintain their electrical insulation at not only high electric fields but also elevated temperatures, in order to meet the growing needs for renewable energies and grand electrifications. Here, a sandwiched barium titanate/polyamideimide nanocomposite with reinforced interfaces via two-dimensional nanocoatings is presented. It is demonstrated that boron nitride and montmorillonite nanocoatings can block and dissipate injected charges, respectively, to present a synergetic effect on the suppression of conduction loss and the enhancement of breakdown strength. Ultrahigh energy densities of 2.6, 1.8, and 1.0 J cm-3 are obtained at 150 °C, 200 °C, and 250 °C, respectively, with a charge-discharge efficiency >90%, far outperforming the state-of-the-art high-temperature polymer dielectrics. Cyclic charge-discharge tests up to 10 000 times verify the excellent lifetime of the interface-reinforced sandwiched polymer nanocomposite. This work provides a new pathway to design high-performance polymer dielectrics for high-temperature energy storage via interfacial engineering.

Cu2O/2D COFs Core/Shell Nanocubes with Antiphotocorrosion Ability for Efficient Photocatalytic Hydrogen Evolution.

Photocorrosion of highly active photocatalysts is an urgent problem to be solved in the field of photocatalysis; however, searching for effective strategies for inhibiting photocorrosion of photocatalysts is still a grand challenge. Herein, we design and construct a class of Cu2O/2D PyTTA-TPA COFs (PyTTA: 1,3,6,8-Tetrakis(4-aminophenyl)pyrene, TPA: p-benzaldehyde) core/shell nanocubes to greatly boost the performance of photocatalytic hydrogen evolution and significantly inhibit the photocorrosion. The optimal Cu2O/PyTTA-TPA COFs core/shell nanocubes exhibit an excellent photocatalytic H2 evolution rate of 12.5 mmol h-1 g-1, which is ∼8.0-fold and ∼20.0-fold higher than those of PyTTA-TPA COFs and Cu2O nanocube, respectively, and also is the best in all the reported metal oxides catalytic materials. The mechanism studies demonstrate that the appropriate matching band gaps and tight integration of PyTTA-TPA COFs and Cu2O nanocubes can significantly facilitate the separation of photogenerated electron-hole pairs in the Cu2O/PyTTA-TPA COFs core/shell nanocube during the photocatalytic process, which ameliorates the photocatalytic H2 evolution activity. Most importantly, the 2D PyTTA-TPA COFs shell with outstanding intrinsic stability protects Cu2O nanocubes core from photocorrosion by showing no morphology and crystal structure change after 1000 times of photoexcitation.

Grain refinement in titanium prevents low temperature oxygen embrittlement.

Interstitial oxygen embrittles titanium, particularly at cryogenic temperatures, which necessitates a stringent control of oxygen content in fabricating titanium and its alloys. Here, we propose a structural strategy, via grain refinement, to alleviate this problem. Compared to a coarse-grained counterpart that is extremely brittle at 77 K, the uniform elongation of an ultrafine-grained (UFG) microstructure (grain size ~ 2.0 µm) in Ti-0.3wt.%O is successfully increased by an order of magnitude, maintaining an ultrahigh yield strength inherent to the UFG microstructure. This unique strength-ductility synergy in UFG Ti-0.3wt.%O is achieved via the combined effects of diluted grain boundary segregation of oxygen that helps to improve the grain boundary cohesive energy and enhanced dislocation activities that contribute to the excellent strain hardening ability. The present strategy will not only boost the potential applications of high strength Ti-O alloys at low temperatures, but can also be applied to other alloy systems, where interstitial solution hardening results into an undesirable loss of ductility.

A one-dimensional conductive metal-organic framework with extended π-d conjugated nanoribbon layers.

Conductive metal-organic frameworks (MOFs) have performed well in the fields of energy and catalysis, among which two-dimensional (2D) and three-dimensional (3D) MOFs are well-known. Here, we have synthesized a one-dimensional (1D) conductive metal-organic framework (MOF) in which hexacoordinated 1,5-Diamino-4,8-dihydroxy-9,10-anthraceneedione (DDA) ligands are connected by double Cu ions, resulting in nanoribbon layers with 1D π-d conjugated nanoribbon plane and out-of-plane π-π stacking, which facilitates charge transport along two dimensions. The DDA-Cu as a highly conductive n-type MOF has high crystalline quality with a conductivity of ~ 9.4 S·m-1, which is at least two orders of magnitude higher than that of conventional 1D MOFs. Its electrical band gap (Eg) and exciton binding energy (Eb) are approximately 0.49 eV and 0.3 eV, respectively. When utilized as electrode material in a supercapacitor, the DDA-Cu exhibits good charge storage capacity and cycle stability. Meanwhile, as thse active semiconductor layer, it successfully simulates the artificial visual perception system with excellent bending resistance and air stability as a MOF-based flexible optoelectronic synaptic case. The controllable preparation of high-quality 1D DDA-Cu MOF may enable new architectural designs and various applications in the future.

Synthesis and characterization of magnetic organic montmorillonite: efficient adsorption of hexavalent chromium.

This research compared two potential adsorbents for the efficient adsorption of toxic hexavalent chromium. The non-magnetic material STAC-Mt and the magnetic material FeSO4-STAC-Mt were synthesized by a simple impregnation method using montmorillonite (Mt), octadearyl dimethyl ammonium chloride (STAC) and ferrous sulfate as raw materials. The structural and morphological characteristics of both adsorbents were investigated by BET, XRD, FTIR, Zeta, VSM, TEM, SEM and XPS techniques. SEM and TEM results clearly revealed that FeSO4-STAC-Mt had a more loosely curled structure than STAC-Mt and the existence of well dispersed diamond-shaped magnetic particles. The saturation magnetization intensity of 17.949 emu/g obtained by VSM further confirmed the presence of magnetite particles in FeSO4-STAC-Mt. Due to the superparamagnetic properties of magnetite, the adsorption performance of FeSO4-STAC-Mt was better than STAC-Mt. FeSO4-STAC-Mt adsorbed up to 43.98 mg/g of Cr(VI), meanwhile it was easily separated from the reaction mixture by an external magnetic field. Intermittent adsorption studies at pH, adsorbent dosage and time revealed a rapid Cr(VI) adsorption process. In combination with response surface optimization analysis, a removal rate of 98.03% of Cr(VI) was obtained at pH 5-6. The adsorption process was properly described by the pseudo-second-order kinetic equation and the Langmuir equation, and the adsorption process was chemisorption and single molecular layer adsorption. In addition, the removal of Cr(VI) reached 72.68% after five cycles, demonstrating the good stability of the FeSO4-STAC-Mt.

Intercepting Elusive Intermediates in Cu-Mediated CO Electrochemical Reduction with Alkyl Species.

Understanding of the reaction network of Cu-catalyzed CO2/CO electroreduction reaction [CO(2)RR] remains incomplete despite intense research efforts. This is in part because the rate-determining step occurs early in the reaction network, leading to short lifetimes of subsequent surface-bound intermediates, the knowledge of which is key to selectivity control. In this work, we demonstrate that alkyl groups can effectively couple with surface intermediates in the Cu-catalyzed CORR and, for the first time, intercept elusive C1 and C2 intermediates. Combined reactivity data and in situ spectroscopic results demonstrated that surface-bound alkyl groups derived from the corresponding alkyl iodides are able to couple with adsorbed CO to form carboxylates and ketones via one and two successive nucleophilic attacks, respectively. Leveraging this new chemistry, CHx (x ≤ 3) and C2Hx (x ≤ 4) are intercepted and identified as precursors for methane and n-propanol in the CORR, respectively. Importantly, reaction pathways leading to methane and C2+ products are not intrinsically orthogonal, but their connection is mainly impeded by low coverages of energetic intermediates. This study shows that perturbing the reaction of interest by introducing a slightly interacting probe reaction network could be an effective and general strategy in mechanistic studies of catalytic reactions.

Indexing of superimposed Laue diffraction patterns using a dictionary-branch-bound approach.

X-ray Laue diffraction is an important method for characterizing the local crystallographic orientation and elastic strain in polycrystalline materials. Existing analysis methods are designed mainly to index a single or a few Laue diffraction pattern(s) recorded in a detector image. In this work, a novel method called dictionary-branch-bound (DBB) is presented to determine the crystallographic orientations of multiple crystals simultaneously illuminated by a parallel X-ray incident beam, using only the spot positions in a detector image. DBB is validated for simulated X-ray Laue diffraction data. In the simulation, up to 100 crystals with random crystallographic orientations are simultaneously illuminated. Fake spots are randomly added to the detector image to test the robustness of DBB. Additionally, spots are randomly removed to test the resilience of DBB against true spots that are undetected due to background noise and/or spot overlap. Poisson noise is also added to test the sensitivity of DBB to less accurate positions of detected spots. In all cases except the most challenging one, a perfect indexing with a mean angular error below 0.08° is obtained. To demonstrate the potential of DBB further, it is applied to synchrotron microdiffraction data. Finally, guidelines for using DBB in experimental data are provided.

Effects of psychological factors on players’ performance with the mediation role of player’s satisfaction / Efectos de los factores psicológicos en el desempeño de los jugadores con el papel de mediación de la satisfacción del jugador

Nowadays, most of the players from Chinaare unable to perform outstandingly because of the effects of psychological factors which limit them and it is very common that these factors even don’t allow the players to perform accordingly. Hence, the primary objective of the current study is to investigate the role of psychological factors which affect a player’s performance particularly with the mediation role of the player’s satisfaction.To obtain the outcomes of the current study, a quantitativeresearch approach was adopted. 760 football playerswho were the respondents of the current study were surveyed for the collection of primary data. Partial Least Square (PLS) was used to evaluate the final outcomes from the primary data.From the outcomes of the current study, it is obvious that a player’spsychological factors such as punctuality, mood, competition, and commitment have a positive effect on the player’s satisfaction and performance.The current study is helpful for the players particularly from Chinato boost their performances and satisfaction level. Moreover, the current study also helps the sports industry of Chinato increase players’ performances.(AU)

Single Atom Catalysts with Out-of-Plane Coordination Structure on Conjugated Covalent Organic Frameworks.

Adjusting the local coordination environment of single-atom electrocatalysts is a viable way to improve catalytic performance. The diversity of coordination geometric structures is limited to the traditional in-plane configuration, with only a little consideration paid to out-of-plane configurations due to the lack of suitable carriers and fabrication methods. This study reports out-of-plane coordination of Co-based single-atom catalysts mediated by the conjugated bipyridine-rich covalent organic framework (COF). The bipyridine nitrogen on the COF layer backbone of these catalysts serves as the linker center for cobalt sites anchoring, while the complementary moieties are coordinated at the other side of the Co metal and reside beyond the COF backbone plane, thus yielding out-of-plane coordination. The electrochemical experiments and density functional theory calculations reveal that catalysts with multiple out-of-plane coordinations exhibit different electrocatalytic oxygen evolution activities and catalytic pathways. The out-of-plane coordination enabled by COFs provides a strategy for designing single-atom electrocatalysts, expanding the application of COFs in the field of electrocatalysis.

Construction of an aggregation-induced electrochemiluminescent sensor based on an aminal-linked covalent organic framework for sensitive detection of glutathione in human serum.

We demonstrate the construction of an aggregation-induced electrochemiluminescent (AIECL) sensor for glutathione (GSH) assay by integrating an aminal-linked covalent organic framework (A-COF) with manganese dioxide (MnO2) nanosheets. The AIECL of the A-COF is quenched by the MnO2 nanosheets via electrochemiluminescent resonance energy transfer (ERET) from the excited A-COF to MnO2. The presence of GSH can reduce the MnO2 nanosheets into Mn2+, restoring the AIECL emission of the A-COF. This AIECL sensor has the characteristics of fast response, high sensitivity, and good selectivity toward GSH, and it can accurately measure GSH in human serum.

An effective strategy for improving charge separation efficiency and photocatalytic degradation performance using a facilely synthesized oxidative TiO2 catalyst.

Titanium dioxide (TiO2) has attracted enormous interest in abundant photocatalytic reactions, but its photocatalytic efficiency is limited by its wide bandgap and the rapid recombination of electron-hole pairs. To overcome the disadvantages of its rapid electron-hole recombination rate, herein, oxidative TiO2 was one-step fabricated using potassium permanganate (KMnO4), exhibiting improved charge separation efficiency and photocatalytic degradation performance towards methyl orange (MO). Remarkably, the first-order photodegradation rate of oxidative TiO2 is 3.68 times higher than that of pristine TiO2 under the irradiation of simulated sunlight and 2.15 times higher under ultraviolet light. This exceptional photocatalytic activity is attributed to the additional oxygen doped into the interstices of the TiO2 lattice, creating impurity states in the bandgap acting as trapping sites, thus facilitating charge separation. This work provides a promising strategy for the insertion of O atoms into the TiO2 lattice and expands the photocatalytic application of the related materials.