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Few-atom-thick two-dimensional (2D) molybdenum disulfide (MoS2) monolayers possess numerous crucial applications in energy storage. Usually, the strategy of activating interfacial electron transfer was employed to promote their performance. Herein, we reshape the structure of materials to excite their subinterfacial and interfacial electron transfer for superior metal-ion batteries. As an example, we rationally design and reconfigure the structure of 2D MoS2 and propose a new stable structure, B-MoS2, which has an S–Mo–S sandwich structure with a buckled square lattice. The B-MoS2 monolayer is a promising anode material for magnesium-ion batteries (MgIBs) with a high capacity (921.3 mA h g−1) and a low averaged open circuit voltage (0.154 V). Multiscale underlying mechanisms for the storage of Mg and Li ions in MoS2 are provided. Based on the electronic level, the high capacity is ascribed to the occurrence of interfacial and subinterfacial electron transfer between metal ions and B-MoS2. Based on the atomic level, the insertion-adsorption mechanism or adsorption-insertion mechanism is determined for different ion storage at B-MoS2. The intrinsic metallic property of B-MoS2 and the enhanced electronic conductivity of Mg/B-MoS2 systems as well as low migration barriers (∼0.604 eV) of Mg ions at MoS2 suggest that the B-MoS2 anode has fast charge/discharge rates. This work offers novel concepts (i.e. subinterfacial electron transfer and its activation) for superior energy storage materials, and proposes new multiscale underlying mechanisms for ion storage in the MoS2 family.

Plasmonic hotspots can enhance hot charge carrier generation, offering new opportunities for improving the photocatalytic activity. In this work, eight types of heteronanostructures are synthesized by selectively depositing catalytic metals at the different sites of highly asymmetric Au nanocups for the photocatalytic oxidation of o-phenylenediamine. The oxidation of this molecule has so far mainly relied on the use of H2O2 as an oxidizing agent in the presence of an appropriate catalyst. The photocatalytic oxidation under visible light has not been reported before. The Au nanocups with AgPt nanoparticles grown at the opening edge and bottom exhibit the highest photocatalytic activity. The generated hot electrons and holes both participate in the reaction. The hot carriers from the interband and intraband transitions are both utilized. The optimal catalyst shows a favorable activity even under room light. Simulations reveal that the profound electric field enhancement at the hotspots boosts the hot-carrier density in the catalytic nanoparticles, explaining the overwhelming photocatalytic activity of the optimal catalyst.

Benefiting from the superior conductivity, rich surface chemistry and tunable bandgap, Ti3C2 MXene has become a frontier cocatalyst material for boosting the efficiency of semiconductor photocatalysts. It has been theoretically predicted to be an ideal material for N2 fixation. However, the realization of N2 photofixation with Ti3C2 as a host photocatalyst has so far remained experimentally challenging. Herein, we report on a sandwich-like plasmon- and an MXene-based photocatalyst made of Au nanospheres and layered Ti3C2, and demonstrate its efficient N2 photofixation in pure water under ambient conditions. The abundant low-valence Ti (Ti(4−x)+) sites in partially reduced Ti3C2 (r-Ti3C2) produced by surface engineering through H2 thermal reduction effectively capture and activate N2, while Au nanospheres offer plasmonic hot electrons to reduce the activated N2 into NH3. The Ti(4−x)+ active sites and plasmon-generated hot electrons work in tandem to endow r-Ti3C2/Au with remarkably enhanced N2 photofixation activity. Importantly, r-Ti3C2/Au exhibits ultrahigh selectivity without the occurrence of competing H2 evolution. This work opens up a promising route for the rational design of efficient MXene-based photocatalysts., N2 photofixation in water is realized under ambient conditions using partially reduced Ti3C2 MXene that is interlaminated with Au nanospheres.

Nitrogen fixation is an essential process for sustaining life. Tremendous efforts have been made on the photodriven fixation of nitrogen into ammonia. However, the disproportionation of dinitrogen to ammonia and nitrate under ambient conditions has remained a grand challenge. In this work, the photodriven disproportionation of nitrogen is realized in water under visible light and ambient conditions using Fe-doped TiO2 microspheres. The oxygen vacancies associated with the Fe dopants activate chemisorbed N2 molecules, which can then be fixed into NH3 with H2 O2 as the oxidation product. The generated H2 O2 thereafter oxidizes NH3 into nitrate. This disproportionation reaction can be turned to the reductive one by loading plasmonic Au nanoparticles in the doped TiO2 microspheres. The generated H2 O2 can be effectively decomposed by the Au nanoparticles, resulting in the transformation of the disproportionation reaction to the completely reductive nitrogen photofixation.

Light-harvesting capacity and photoexcited charge carrier separation ability are two crucial requirements for high-efficiency semiconductor photocatalysis. Here, we report a plasmonic Z-scheme nanohybrid by hydrothermally in-situ growing two-dimensional (2D) oxygen-deficient molybdenum oxide (MoO3-x) nanoplates onto 2D graphitic carbon nitride (g-C3N4) nanosheets. The resultant 2D/2D MoO3-x/g-C3N4 nanohybrids not only construct a unique Z-scheme heterojunction, which improves the photogenerated charge carrier separation efficiency, but also possess numerous oxygen vacancies on the surface of MoO3-x, which could excite its plasmon resonance for extending spectrum adsorption. Importantly, the plasmon resonance can be readily designed by tailoring the oxygen vacancy concentration via an annealing in air. Benefiting from the synergetic effect of interfacial Z-scheme heterojunction and the tunable plasmon resonance of MoO3-x, the as-obtained nanohybrids achieve a remarkably improved photocatalytic H2 evolution efficiency. The optimal Z-scheme heterostructure presents 2.6 and 1.7 times higher of H2 evolution rate as compared to pure g-C3N4 and the annealing nanohybrid under visible light irradiation. Even under light irradiation with wavelength longer than 590 nm, the hybrid photocatalyst displays a H2 generation rate as high as 22.8 µmol h−1 due to the plasmonic sensitization effect. The result in our work can provide an alternative for fabricating Z-scheme heterostructures that take advantages of Z-scheme-induced charge carrier separation, accompanied with plasmon-enhanced light harvesting of semiconductor to advance the solar energy conversion efficiency in photocatalysis.

Three-dimensional porous carbon materials play a significant role in gas separation and energy storage. However, their low performances in energy storage hamper their applications. Herein, we propose a new possible category of carbon honeycomb (CHC), i.e. CHCs with asymmetrical channels (denoted as asymmetrical CHCs), to increase their performance. As an example, by cross-linking graphene sheet with sp3–hybridized carbon chains, we prepare a new 3D porous asymmetrical CHC, i.e. bco-C24. It is dynamically, thermally, and mechanically stable. Our first-principles calculations and tight binding results demonstrate that it possesses a significant electronic band structure of Dirac nodal lines, which are ascribed to the px and py orbitals of α carbon atoms in the graphene ribbons that have both α and β carbon atoms. It provides high carrier mobility between 7.98 × 105 and 9.99 × 105 m/s. It has high theoretical capacities (743.8/495.9/991.8/743.8 mA h/g), low diffusion barriers (0.077/0.032/0.117/0.169 eV), low average voltages, and negligible volume changes for Na/K/Ca/Li-ion batteries. This study not only constructs a new concept of asymmetrical CHCs and provides a strategy of cross-linking graphene sheets to create its sample structures, but also suggests new carriers for ion storage in the superior next generation metal-ion battery anodes.

Ammonia, one of the most important chemicals and an efficient energy carrier, is industrially synthesized by the energy-intensive Haber–Bosch process. Photocatalytic nitrogen fixation under ambient conditions provides an intriguing approach for the conversion of atmospheric dinitrogen into ammonia. Herein we report a plasmonic hybrid catalyst composed of Au nanoparticles uniformly embedded in the mesopores of nitrogen-deficient hollow carbon nitride spheres for efficient nitrogen photofixation. The nitrogen vacancies in the carbon nitride spheres, serving as the sites for nitrogen chemisorption and activation, capture photoexcited electrons originating from the carbon nitride spheres and the plasmon resonance of the embedded Au nanoparticles for the reduction of nitrogen to ammonia. The designed structure can maximize the utilization efficiency of the plasmonic effect of the Au nanoparticles, as well as the nitrogen activation effect of the nitrogen vacancies in the carbon nitride spheres, therefore promoting the photoreduction of nitrogen. The optima Au-embedded carbon nitride spheres achieve an ammonia production rate of 783.4 μmol h−1 gcat−1 under visible light. The interfacial plasmon-induced charge separation endows the hybrid photocatalyst with the capability of simultaneous production of ammonia and oxygen with a solar-to-ammonia conversion efficiency of 0.032% under simulated sunlight.

Surface-enhanced infrared absorption (SEIRA) can dramatically enhance the vibrational signals of analyte molecules owing to the interaction between plasmons and molecular vibrations. It has huge potential for applications in various detection and diagnostic fields. High-aspect-ratio rod-like metal nanostructures have been the most widely studied nanomaterials for SEIRA. However, nearly all of the rod-like nanostructures reported previously are fabricated using physical methods. They suffer from damping and low areal number densities. In this work, high-aspect-ratio Au nanorods are synthesized, and Au nanonails are prepared through Au overgrowth on the as-prepared Au nanorods. The aspect ratios of the Au nanorods and nanonails can be varied in the range of ∼10 to ∼60, and their longitudinal dipolar plasmon resonance wavelengths can be correspondingly tailored from ∼1.6 to ∼8.3 μm. The Au nanonails exhibit superior SEIRA performance with 4-aminothiophenol used as the probe molecules. They are further used to detect the common biomolecule l-cysteine. Numerical simulations are further performed to understand the experimental results. They match well with the experimental observations, revealing the mechanism of the SEIRA enhancement. Our study demonstrates that colloidal high-aspect-ratio Au nanonails and nanorods can function as SEIRA nanoantennas for highly sensitive molecular detection in various situations.

An ultrasensitive sandwich-type electrochemical immunosensor based on AuBP@Pt nanostructures and AuPd-PDA nanozyme was developed for the detection of apolipoprotein E4 (APOE4) which was an important risk factor for Alzheimer's disease (AD). In this work, gold nanobipyramid coated Pt (AuBP@Pt) nanostructures were prepared and applied to electrochemical immunosensors as a substrate material. AuBP@Pt nanostructures have advantages of electrical conductivity and large electroactive area, which could greatly increase electron transfer rate. In previous work, we designed AuPd alloy modified polydopamine (AuPd-PDA) nanozyme which catalyzed the decomposition of hydrogen peroxide (H2O2). AuPd-PDA nanozyme was used to label detection antibody due to excellent catalytic capability and stability in this new paper. And the concentration of APOE4 could be detected quantitatively by variation for transient current. As a result, the electrochemical immunosensor based on AuBP@Pt and AuPd-PDA exhibited a wide linear range from 0.05 to 2000 ng mL−1 and low detection limit of 15.4 pg mL−1 (S/N = 3). Furthermore, the designed biosensor displayed good selectivity in phosphate buffer saline (PBS) buffer solution or commercial goat serum, which provided a promising tool for early diagnosis of AD.

CuBDC MOFs can realize the sensitive and accurate colorimetric detection of S2− in water based on two complementary mechanisms. As reactive metal centers in MOFs for S2− responding, Cu2+ ions can be taken out from the MOF nodes by S2−, inducing the generation of sandy brown CuS. The ratio of blue CuBDC MOFs and sandy brown CuS in an aqueous solution is varied with the amount of S2− added, leading to visual changes in the solution color according to the principle of pigment mixing. The presence of S2− can be indirectly confirmed and quantitatively monitored through the UV-Vis spectrophotometry since the capture of Cu2+ by S2− can induce the recovery of uncoordinated carboxyl groups in CuBDC MOFs accompanied by the increase in absorbance intensity. Moreover, CuBDC MOFs can be immobilized in polyvinyl alcohol (PVA) gels to form test strips that can realize S2− detection in water samples with a linear range of 10–100 μM. Additionally, the PVA gels can be dried, accompanied by arbitrary bending deformations for the portable detection of S2− in water. The design strategy based on two complementary mechanisms promises to provide an accurate, sensitive and portable colorimetric assay for S2− detection in water.

The rapid development of stretchable electronics, which have wide applications from clinical applications to stretchable smart phones, requires numerous advanced stretchable energy technologies, such as stretchable batteries. However, maintaining performance in such batteries during deformation and developing stretchable batteries with suitable mechanical robustness for industrial applications remain challenges. In this work, by using first-principles calculations, the performance of three-dimensional (3D) topological semimetal porous carbon material bct-C40 anodes in stretchable lithium-ion batteries (LIBs) is investigated. We find that the mechanical deformation is a feasible route for reconfiguration of inner surfaces of porous carbon material anodes to modulate their high performance in stretchable LIBs. The bct-C40 anode delivers a high theoretical capacity of 893 mA h/g, which is approximately 2.4 times larger than that of the commercial graphite anode (372 mA h/g). Adsorption-activation-adsorption mechanism and (de)activation-adsorption mechanism are proposed for the capacities of the anode under strain-free and strained states, respectively. Under the strain-free state, the adsorption of Li atoms changes the size of porous of bct-C40 at the atomic scale and readjusts the electron distribution on bct-C40 at the electronic scale, activating more adsorption sites. Large tensile strains expand its inner space and inner surface area, forming new adsorption sites and boosting its high capacities. Large compressive strains undermine its inner surface and deactivate some adsorption sites, reducing its capacities. Small compressive and tensile strains play a little role in the inner surface and do not affect adsorption sites, retaining its high capacities. More excitingly, diffusion barriers under strain-free and strained states, which are sensitive to the inner surface, are (ultra)low, demonstrating that the anode has (ultra)fast charge/discharge rates. This work provides new insights for the modulatable performance of 3D porous carbon material anodes, and offers an approach to innovate high performance stretchable metal-ion battery anodes with suitable mechanical robustness.

We develop pH-responsive GOD@CaCO3-Fe3O4 particles as catalytic nanomedicine for chemodynamic therapy through ultrasound-assisted Fenton reaction. By loading glucose oxidase (GOD) in the interior of the particles, GOD can be well protected and effectively delivered to catalyze glucose in cancer cells. A considerable amount of H2O2 is then generated for Fenton reaction by reacting with Fe3O4 nanoparticles. The introduction of ultrasound irradiation can significantly improve Fenton reaction efficiency in tumors owing to ultrasonic cavitation. Highly toxic hydroxyl radicals are then generated in abundance to kill cancer cells. Good cancer therapeutic effect was realized both in vitro and in vivo via this ultrasound-chemodynamic strategy based on the designed particles, providing a novel strategy for efficient cancer therapy.

Auxetic materials possess special applications due to their unique negative Poisson's ratios (NPRs). As a classic 2D carbon material, the NPR of graphene is still deliberated. Introducing the NPR in graphene would increase its extraordinary properties, and the NPR together with other properties would bring more significant applications for graphene. In this Letter, on the basis of first-principles calculations, we reconfigure the structure of graphene, and, as an example, we propose a new 2D planar carbon allotrope, xgraphene, which is constructed by 5-6-7 carbon rings. Our theoretical calculations indicate that xgraphene has an NPR and constitutes a broad spectrum of metal ion battery anodes with high performance. Its maximum storage capacities are 930/1302/744/1488 mAh/g for Li/Na/K/Ca-ion batteries. It has low metal-ion diffusion energy barriers (≤0.49 eV) and low average open-circuit voltages (≤0.53 V). Our density functional theory results also showed that it is intrinsically metallic and possesses dynamic, thermal, and mechanical stabilities. Its intrinsic NPR, which stems from the weakness of coupling of carbon-carbon bonds, is found upon loading the uniaxial strain along the armchair direction. This work not only opens up a new direction for the design of the next-generation broad-spectrum energy-storage materials with low cost and high performance but also offers a class application for auxetic materials.

Electrochemically active organic materials are one of the best choices for replacing metal-based electrode materials in energy storage devices for their advantages of low cost, high capacitance, high safety performance and abundant reserves. In this paper, 1-aminopyrene and reduced graphene oxide nanosheets composites are successfully synthesized via solvothermal method. When used as electrochemically active organic material, it demonstrates that the nanocomposites electrodes show high capacitances with wonderful super-long cycle stabilities under the synergistic effect of various components. The as-obtained AprC2 electrode displays a capacitance as high as 381.48 F g−1 at 0.6 A g−1 and an superior rate performance. Furthermore, a high energy density of 43.67 W h kg−1 (0.72 kW kg−1) with excellent super-long cycle stability for over 12,000 cycles is obtained. These results strongly demonstrate that the easily synthesized electrode materials are very promising to replace metal-based composites to fabricate the next generation energy storage devices.

The sensitivity of plasmonic sensors in response to the refractive index changes of the surrounding medium is highly dependent on the shape of metal nanocrystals. In this work, the bulk refractive ...

Poplar catkins are an environmental pollutant because they can trigger sneezing, shortness of breath, skin allergy and even cause forest fire. It is very attractive to discover ways for reducing the threats of poplar catkins to the environment and human health and even to convert poplar catkins into useful materials. Herein we report on a facile and cost-efficient strategy for the synthesis of hierarchical porous carbon microtubes using poplar catkins as the carbon source. The synthesis involves pre-carbonization and subsequent ZnCl2 activation. The resultant materials not only inherit the natural tubular morphology of poplar catkins, but also develop a hierarchical porous structure, with nitrogen from the biomass being self-doped in the resultant carbon skeleton. The hierarchical porosity, especially the microporosity with the pore size from 0.5 to 1 nm, surface structure, tube wall thickness and nitrogen content can be readily controlled by adjusting the activation temperature and the ZnCl2-to-precursor mass ratio. The produced materials exhibit an excellent CO2 capture capacity. The optimal sample activated at 800 °C with a ZnCl2-to-precursor mass ratio of 4:1 shows an extraordinarily high CO2 adsorption capacity of 6.22 and 4.05 mmol g−1 at 273 and 298 K, respectively, at 1 bar of CO2. Furthermore, the material also displays an excellent recyclability and CO2/N2 selectivity. Our approach not only relieves the environmental pollution of poplar catkins but also leads to the production of a high-performance CO2 adsorbent, which is promising for industrial CO2 capture and separation. It therefore demonstrates an example of trash-to-treasure transformation.

Electron transfer plays a crucial role in energy storage materials, such as metal-ion batteries (MIBs). Numerous approaches have been developed to facilitate the electron transfer for MIBs, and most of them extend the special surface areas, which promotes the contact between metal ions and the electrodes. Herein, we report the formation of intramolecular channels for electron transfer to open and close intermolecular channels in sodium-ion batteries (SIBs) through functionalization, modulating the cell performance of two-dimensional (2D) nitrogenated holey graphene C2N anodes. This also activates the inactive metal ions in the anodes, reducing their production costs. Upon increasing the concentration of hydrogen atoms, the intramolecular electron transfer increases, lowering the intermolecular electron transfer between C2N and metal ions and thus weakening their interaction and reducing the capacities of the anodes. A high concentration of hydrogen atoms introduced in C2N would further promote the intramo...

Reconfiguring structures in materials is one of the most important building approaches in new material design. The atomically precise control of reconfiguration of two-dimensional (2D) carbon-based materials reshapes their properties for engineering applications. Herein, by employing density functional theory and tight-binding modeling, we reconfigured atomically precise structure in graphene and proposed a new 2D carbon allotrope Θ-graphene. The reconfiguring procedure adopted was realized in experiments using an electron beam. It exhibits semiconductor features with a bandgap of 0.58 eV, and is extendable to semimetal or metal. Mechanically-induced directional-dependent topological node line states are formed and their origin is the breaking of the geometrical symmetry. The reconfiguring procedure reshapes the adsorption and diffusion properties of Θ-graphene, promoting its storage capacities for metal ions (876.65/1275.12/956.34 mA h/g for Li/Na/K- ion batteries) and lowing its metal ion-diffusion energy barriers (≤ 0.48 eV) and lowing its average open circuit voltages (≤ 0.60 V). The transition from semiconductor to metal with metal ions introduced improves its high electronic conductivity, which could be beneficial to the fast charge/discharge rates. Our results show that the reconfigured structure in graphene reshapes its properties, bringing it numerous promising engineering applications such as in metal-ion batteries and in nanoelectronic devices and in energy storage. This work provides a new channel for materials design and innovation by combining the reconfiguring strategy and the structure-property-application relationship, and opens up a new strategy to extend the applications of low-dimensional materials such as graphene and to promote their application performance.

The highly efficient detection method for hydrogen peroxide (H2O2) has been attracting significant attention. In this study, AuPd alloy-modified polydopamine (AuPd-PDA) nanotubes were prepared, and an electrochemical nonenzymatic sensor based on the AuPd-PDA nanotubes was developed. A single AuPd alloy on the surface of PDA nanotubes consisted of many smaller nanoparticles of size ranging several nanometers, which greatly enhanced the catalytic activity. In addition, PDA nanotubes, as carriers of AuPd alloys, were used to amplify the signal and improve the sensitivity of H2O2 sensors. Owing to its synergistic effect and structural advantage, the H2O2 sensor based on AuPd-PDA nanotubes exhibited good sensing performances, including a high sensitivity of 314.2 μA mM−1 cm−2, a wide linear range from 1.0 μM to 11.22 mM and a low detection limit of 0.26 μM (S/N, 3 : 1). Moreover, the detection of H2O2 in HeLa and Raw 264.7 cells was also achieved, which indicated that the sensors based on AuPd-PDA nanotubes could be used for real-time monitoring of H2O2 in physiological and pathological processes in a clinic.

Efficient intersystem crossing (ISC) and reverse ISC (RISC) are of central importance in thermally activated delayed fluorescence (TADF) materials to harvest both singlet and triplet excitons for electroluminance with theoretically 100% internal quantum efficiency. However, facile and accurate prediction of the ISC and RISC rates of TADF molecules in donor–acceptor architectures is challenging. Herein, we investigated five theoretical methods in simulating the ISC and RISC processes based on six typical TADF molecules. Both the singlet–triplet energy splitting (ΔEST) and spin–orbit coupling (SOC) were evaluated at the density functional theory (DFT) and time-dependent DFT levels using frontier orbital energy levels and overlap extents, n-orbital composition and electronic density transition analyses, and natural transition orbital (NTO) studies on the ground or excited state structures. Compared to the experimental results, NTO and n-orbital analyses based on the configuration of the lowest triplet excited state were found to be the most applicable approaches in predicting credible ISC and RISC rates in low computational costs, offering facile and reliable approaches to computational screening for high-performance TADF materials. This work could provide important clues for not only the fundamental understandings of facilitating ISC and RISC processes but also efficient computational methods in predicting high-performance TADF materials.

Stretchable batteries play a central role in stretchable electronics such as healthcare devices and sensors. However, challenges in stretchable batteries, such as unstable performance during the deformation process and their mechanical resistances, slow down their applications. In this paper, by adopting state-of-the-art first-principles calculations, the high performance of two-dimensional (2D) nitrogenated holey graphene C2N based stretchable magnesium-ion batteries (MgIBs) and its origin are determined. Their maximum capacity and average open circuit voltage are 1175 mA h g−1 and 0.447 eV, respectively, in the strain-free state, which are much more superior to most of the previously reported 2D anode materials. Mechanical activation is a facile and effective approach to induce charge redistribution to promote their high performance, i.e. their capacities are promoted under large compressive and tensile strains, whereas their high capacities are maintained under small compressive and tensile strains. The origin of the high performance of stretchable MgIBs is also proposed based on the evidence of electron localization function and charge density difference. Compressive and tensile strains remodulate the structures of electrode materials at the atomic scale and redistribute the electrons at the electronic scale, resulting in the reactivation of adsorption sites in electrode materials and maintaining the high performance of stretchable MgIBs. Additionally, large compressive strains enhance the stability of the C2N/Mg system, further increasing its capacities. The stretchable battery shows a two-stage diffusion mechanism in strain-free and strained states, i.e. in the first stage, the out-of-plane Mg ions diffuse quickly, and in the second stage, the in-plane Mg ions migrate moderately. Compared with the stretchable battery in the strain-free state, its barrier energies are lowered in the strained states. This study provides new insights and microscale mechanisms for non-stretchable and stretchable batteries with high performance and facilitates the innovation of low cost non-stretchable and stretchable batteries with 2D material anodes.

Crab shells derived from discarded seafood bio-waste, are a naturally abundant and sustainable resource, but their difficult solubility limits their processing and applications, resulting in severe environmental pollution. It is very attractive to discover approaches for reducing the threats of crab shells to the environment and even to convert crab shells into useful materials. Herein, we attempted to convert crab shells into three-dimensional (3D) honeycomb-like graphitized hierarchically porous carbons (GHPCs) by a convenient one-step carbonization process simultaneously combining catalytic graphitization and chemical activation routes. The removal of abundant inorganics from crab shells resulted in a unique honeycomb-like structure, and meanwhile a high doping concentration of N element was inherited in the framework of GHPCs. Furthermore, the simultaneous activation/graphitization treatment developed interconnected hierarchical porosity with a large accessible surface area and highly graphitized skeleton. Benefiting from these unique structural characteristics, GHPCs exhibited a remarkable capacitive performance as supercapacitor electrodes. The GHPC electrode delivered a high gravimetric capacitance of 367.4 F g−1 at 1 A g−1 in 6 M KOH electrolyte. More importantly, the electrode showed satisfactory rate capability where an extremely high current density of 100 A g−1 for charge–discharge operation was available in both KOH and Na2SO4 electrolytes. Furthermore, the assembled symmetric flexible all-solid-state capacitor exhibited a high energy density of 11.1 W h kg−1 and a power density of 100.5 W kg−1, as well as a good cycling stability of 90.8% capacitance retention after 10 000 cycles in a PVA/KOH gel electrolyte. Our approach not only relieved the environmental pollution caused by crab shells but also achieved the production of a high-performance supercapacitor electrode, which was promising for industrial energy conversion and storage. It therefore demonstrated an example of trash-to-treasure transformation.

Considering the characteristics of abundant narrow micropores of

“Diversity-enhanced extracts” is an effective method of producing chemical libraries for the purpose of drug discovery. Three rare new cytochalasan derivative chaetoglobosins B1-B3 (1–3) were obtained from chemically engineered crude broth extracts of Chaetomium madrasense 375 prepared by reacting with hydrazine monohydrate and four known metabolite chaetoglobosins (4–7) were also identified from the fungus. The structures were identified by NMR and MS analysis and electronic circular dichroism simulation. In addition, the antiproliferative activities of these compounds were also evaluated, and the drug-resistant activities of cytochalasans were evaluated for the first time. Compound 6 possessed potent activity against four human cancer cells (A549, HCC827, SW620, and MDA-MB-231), and two drug-resistant HCC827 cells (Gefitinib-resistant, Osimertinib-resistant) compared with the positive controls.

The superior ultramicroporosity and enriched surface CO2-philic sites are simultaneously required features for high-efficiency carbon-based CO2 adsorbents. Unfortunately, these characteristics are usually incompatible and difficult to integrate into one porous carbon material. Herein, we report a new copper ions (Cu2+)-assisted dynamic porogen to construct hierarchically microporous carbon nanosheets in a large scale with high heterogeneity for solving such issue. Cu2+ can be equably dispersed in precursor by coordination interactions of COO-Cu and Cu-N, which can anchor more N/O-containing species in final product. The reduced cuprous ions (Cu+) in pyrolysis process functions as a dynamic porogen to tailor uniform ultramicropores. Importantly, copper salt extracted in this synthetic procedure allows cyclic utilization, realizing a green and low-cost process. The obtained carbon sheets possess a graphene-like morphology, a high surface area and a high-proportioned multiscale microporosity, especially a high-density ultramicropores of 0.4–0.7 nm and supermicroproes of 0.8–1.5 nm. The maximized synergistic effect of morphology, high density of multi-sized ultramicroporosity and surface high heterogeneity endow the resultant microporous carbon nanosheets with the remarkable CO2 capture property, including a high uptake, a moderate adsorption heat, a good selectivity and superior recyclability.

There is growing interest in the use of structure-based virtual screening to identify small molecules that inhibit challenging protein-protein interactions (PPIs). In this study, we investigated how effectively chemical library members docked at the PPI interface mimic the position of critical side-chain residues known as "hot spots". Three compound collections were considered, a commercially available screening collection (ChemDiv), a collection of diversity-oriented synthesis (DOS) compounds that contains natural-product-like small molecules, and a library constructed using established reactions (the "screenable chemical universe based on intuitive data organization", SCUBIDOO). Three different tight PPIs for which hot-spot residues have been identified were selected for analysis: uPAR⋅uPA, TEAD4⋅Yap1, and CaV α⋅CaV β. Analysis of library physicochemical properties was followed by docking to the PPI receptors. A pharmacophore method was used to measure overlap between small-molecule substituents and hot-spot side chains. Fragment-like conformationally restricted small molecules showed better hot-spot overlap for interfaces with well-defined pockets such as uPAR⋅uPA, whereas better overlap was observed for more complex DOS compounds in interfaces lacking a well-defined binding site such as TEAD4⋅Yap1. Virtual screening of conformationally restricted compounds targeting uPAR⋅uPA and TEAD4⋅Yap1 followed by experimental validation reinforce these findings, as the best hits were fragment-like and had few rotatable bonds for the former, while no hits were identified for the latter. Overall, such studies provide a framework for understanding PPIs in the context of additional chemical matter and new PPI definitions.

A novel covalent organic framework polymer material that bears conjugated anthraquinone and triazine units in its skeleton has been prepared via a facile one-pot condensation reaction and employed as an anode material for Li-ion batteries. The conjugated units consist of C═N groups, C═O groups, and benzene groups, which enable a 17-electron redox reaction with Li per repeating unit and bring a theoretical specific capacity of 1450 mA h g-1. The polymer also shows a large specific surface area and a hierarchically porous structure to trigger interfacial Li storage and contribute to an additional capacity. The highly conductive conjugated polymer skeleton enables fast electron transport to facilitate the Li storage. In this way, the polymer electrode shows a large specific capacity and favorable cycling and rate performance, making it an appealing anode choice for the next-generation high-energy batteries.

An increasing energy storage property with high rate capability during fast charging at the high current density has been a long-standing challenge for supercapacitors. In this work, a novel nitrogen-enriched graphitized hierarchical porous carbon (NGHPC) was synthesized by a convenient one-step carbonization process from melamine(M)-resorcinol(R)-formaldehyde(F) co-polymeric microspheres using nano γ-Fe2O3 as template, graphitized catalyst precursor and activation promoting agent coupled with ZnCl2 activation. The nano-sized γ-Fe2O3 was reduced to Fe metal and other Fe-containing species in the carbonization process, and Fe served as catalyst to generate perfectly graphitized carbon skeleton, and other nanoparticles acted as the template of macropores. Meanwhile, CO2 which generated from the oxidation reactions of CO and γ-Fe2O3 reacted with carbon to bring the in situ CO2 physical activation, resulting in the promotive tailoring in microporosity. Interestingly, the morphology of the obtaining NGHPC materials could be controlled from spherical aspect to the structure of sphere coated by thin sheet by varying the M/R mass ratio. As supercapacitor electrodes materials, the optimal material achieved an outstanding specific capacitance of 417.5 F g−1 at 0.5 A g−1 in 6 M KOH electrolyte. More importantly, a superb rate capability was also exhibited, and a capacitance of 296.4 F g−1 was still retained at an ultrahigh current density of 100 A g−1. Besides, the assembled symmetric supercapacitor with the optimal material displayed a high integrated energy density of 33.9 Wh kg−1 at a power density of 809.9 W kg−1 within a voltage range of 0–1.8 V in 0.5 M Na2SO4 natural electrolyte and an approximate 84.8% capacitance retention after consecutive 10,000 cycles at 5 A g−1.

With the development of clean and renewable energy, hydrogen produced via photoelectrochemical (PEC) water splitting has attracted considerable attention. However, to develop the photoanodes with stable and excellent PEC ability is still a big challenge. In our work, TiO2 nanorods decorated with boron doped g-C3N4 (BCN/TiO2) is fabricated via thermal polymerization method to improve the PEC performance. The BCN/TiO2 displays 4-fold increase of the photocurrent density (1.01 mA cm−2) at 1.23 V vs. RHE under irradiation (100 mW cm−2, AM 1.5 G). And the onset potential of BCN/TiO2 exhibits a negative shift with 100 mV. Attributed to the broad light absorption of BCN and hetero-junction forming between BCN and TiO2, the IPCE value is increased to 87.8% in 380 nm, and the charge separation and transfer efficiency are both increased. Doping metal-free inorganic material with heteroatoms is a simple and efficient strategy to increase the light absorption within visible light and charge transfer efficiency in PEC and photocatalytic applications.

In this paper, adsorption, hydrogenation and dehydrogenation of C2H on a single atomic layer of bimetallic CoCu were investigated using first-principles calculations. The CoCu bimetallic layer is formed by Cu replacement of partial Co atoms on the top layer of a Co(111) surface. Our adsorption and reaction results showed those sites, which have stronger adsorption energy of C2H, possess higher reactivity. The bimetallic layer possesses higher reactivity than either of the pure monometallic layer. A mechanism of higher reactivity of the bimetallic layer is proposed and identified, i.e. in the bimetallic catalyst, the catalytic performance of one component is promoted by the second component, and in our work, the catalytic performance of Co atoms in the bimetallic layer are improved by introducing Cu atoms, lowing the activation barrier of the reaction of C2H. The bimetallic layer could tune adsorption and reaction of C2H by modulating the ratio of Co and Cu. Results of adsorption energies and adsorption configurations reveal that C2H prefers to be adsorbed in parallel on both the pure Co metallic and CoCu bimetallic layers, and Co atoms in subsurface which support the metallic or bimetallic layer have little effect on C2H adsorption. For hydrogenation reactions, the products greatly depend on the concentration and initial positions of hydrogen atoms, and the C2H hydrogenation forming acetylene is more favorable than forming vinylidene in both thermodynamics and kinetics. This study would provide fundamental guidance for hydrocarbon reactions on Co-based and/or Cu-based bimetallic surface chemistry and for development of new bimetallic catalysts.

Cross-linked microporous carbon beads (MCBs) were successfully synthesized via a green, convenient, and cost-efficient strategy derived from a renewable sugar source. Such an approach avoids the time-consuming procedure and the use of corrosive chemical activating agents and toxic solvents and only involves a simple carbonization process, which makes it to be applicable for rapid and large-scale industrial production of MCB materials. The obtained MCBs possessed well-defined microporous structure, narrow pore size, and high surface area. Particularly, the microporosity of the resultant MCBs could be easily tailored to arise primary pores of size 0.5–0.9 nm by adjusting the carbonization temperature and reaction time, which remarkably favor the CO2 capture. The optimal sample of MCBs-9-5 carbonized at 900 °C for 5 h was characterized by high microporosity (80% of the surface area from micropores), especially ultrahigh narrow microporosity (53% of pore volume from micropores of size

Ni,Fe-based (oxy)hydroxides have been one of the most active catalysts for the oxygen evolution reaction. In this article, reduced graphene oxide supported Ni doped FeOOH (RGO/Ni:FeOOH) was prepared for electrochemical and photoelectrochemical (PEC) water oxidation. The RGO/Ni:FeOOH exhibited a lower over-potential (260 mV at 10 mA cm−2) and smaller Tafel slope (32.3 mV dec−1) than that of the FeOOH and Ni:FeOOH. Such significant enhancement is attributed to Ni doping and RGO, which reduce the over-potential, improve the conductivity and enlarge surface areas. Besides, RGO/Ni:FeOOH decorated the TiO2 nanorods (NRs) was also fabricated for photoelectrochemical (PEC) water oxidation, which exhibited a higher photocurrent density and lower onset potential than that of TiO2 NRs the bare under illumination due to the synergistic effect of RGO and Ni:FeOOH. These results demonstrate the RGO/Ni:FeOOH has great promising as a co-catalyst to improve the PEC performance.

Polymorphism in functional materials offers an excellent platform for comparative investigations of the structure–property relationship and thus the rational design of functional materials with enhanced performances. Here, we report a facile and selective fluorination route to phase-pure gadolinium oxyfluorides crystallizing in orthorhombic (O-GdOF) and rhombohedral (R-GdOF) structures. The phase selectivity can be achieved simply by controlling the reaction temperature and the amount of the fluoridizer (polytetrafluoroethylene). A reversible phase transition from R-GdOF to O-GdOF was observed around 600 °C upon heating and cooling, which was further confirmed by the in situ X-ray diffraction results. Trivalent rare-earth ion (RE3+) doping makes O- and R-GdOF potential bifunctional materials for optical imaging and magnetic resonance imaging (MRI) applications. Under near infrared (NIR) irradiation (980 nm), both RE3+-doped O- and R-GdOF exhibit intriguing visible upconversion (UC) emissions with a tunable G/R ratio (RE = Yb/Ho), near single-peak red emissions around 660 nm (RE = Yb/Er) and NIR emissions around 800 nm (RE = Yb/Tm). RE3+-doped O- and R-GdOF also show discrepant UC profiles in terms of emission intensity, peak shape and G/R ratios attributed to the subtle symmetry differences of the RE3+ doping sites. Besides, the ability of RE3+-doped O- and R-GdOF to serve as T2 weighted MRI contrast agents was evaluated. The results show that R-GdOF performs better than O-GdOF in T2 weighted MRI with higher r2 relaxivity values and r2/r1 ratio. The exploration of more RE oxyfluorides with multimorphism and the comparative studies of their optical performances will provide deep insight into their structure–property relationship and accelerate the rational design of better multifunctional materials.

Hybrid photocatalysts containing plasmonic metal and semiconductor building blocks can alleviate charge carrier recombination and broaden the range of light absorption of the semiconductor. In this work, plasmonic Au nanocrystals of different sizes and shapes (spheres and rods) are attached on graphitic carbon nitride (g-C3N4) nanosheets through electrostatic attraction. The effects of the morphology and loading amount of the Au nanocrystals are carefully studied for understanding and optimizing the hybrid photocatalysts. The optimized 18 nm-sized Au nanospheres/g-C3N4 photocatalyst exhibits a superior activity for H2 evolution at a rate of 540 μmol g-1 h-1 under visible light (λ > 420 nm), exceeding those produced over larger-sized Au nanospheres/g-C3N4, Au nanorods/g-C3N4 and photodeposited Au nanoparticles/g-C3N4 photocatalysts. The excellent activity for H2 evolution is attributed to the electron sink and plasmonic effects of the Au nanocrystals in different spectral regions, as evidenced by photocurrent measurements. The introduced plasmonic Au nanocrystals not only enhance the photocatalytic activity, but they also endow the hybrid photocatalysts with an extended light absorption range. Our results and understanding will be useful for the design of efficient plasmonic photocatalysts for solar to fuel energy conversion as well as for other plasmon-driven chemical reactions.

Classic two-dimensional (2D) graphene possesses outstanding properties due to Dirac cone structures. When scaling up to three-dimensional (3D) structures, their high porosity and large surface-area-to-volume ratio made them have more promising engineering perspectives. However, the currently synthesized and density-functional-theory-predicted 3D graphene structures, termed as carbon honeycombs (CHCs), are metallic. Herein, we propose new families of stable semimetallic CHC structures, which have lower energies than the previous experimentally reported structure and they would be realized experimentally. Results from density functional theory (DFT) and tight binding (TB) model showed that multiple Dirac cones with massless Dirac Fermions are present in both pristine and strained CHCs. Dirac cones in pristine CHCs originated from interactions between sp2-hybridized carbon atoms along the zigzag direction (denoted as CZi, i = α, β,…), while strain-induced direction-dependent Dirac cones primarily stemmed from interactions (i) between the two CZα atoms bonded to a selected sp3-hybridized carbon atom or (ii) between CZi and CAα (α carbon atoms at the armchair direction) atoms. The largest Fermi velocity achieved is 1.204 × 106 m s−1, which is approximately 44.7% larger than that of graphene. These results open up a new direction in carbon-based 3D porous materials and these findings provide significant insights on numerous applications, ranging from nanoelectronics and nanomechanics to gas and liquid separations.

Two-dimensional (2D) carbon allotropes have attracted great attention in both science and engineering fields. Their extraordinary and/or unique properties make them promising for engineering applications, ranging from metal-ion batteries to biosensors. Herein, by employing first-principles calculations, we propose a new 2D planar carbon allotrope, popgraphene, which is composed of 5–8–5 carbon rings. Using a bottom-up approach, popgraphene could be constructed via the formation of atomically precise 5–8–5 line defects in graphene by simultaneous electron irradiation. Popgraphene is intrinsically metallic. It has low energy and possesses great dynamic, thermal and mechanical stability. Our calculations also show that it has a high theoretical capacity for Li atoms (Li4C6: 1487 mA h g−1), a low Li diffusion barrier (

As a widely grown flower plant, the flowers of Cercis chinensis Bunge can treat rheumatism, muscle and bone pain. In order to promote the application of C. chinensis in food and agricultural cultivation, the structure and coagulant activity of pure polysaccharides isolated from flowers were studied, which was of great significance for the further application of C. chinensis. The results showed that two homogeneous heteropolysaccharides, with average molecular weight of 17060 (CCp-1) and 8303 Da (CCp-2), were isolated and identified from C. chinensis flowers. There was little different in their physicochemical properties. GC analysis showed that CCp-1 and CCp-2 were mainly comprised of xylose, rhamnose, arabinose, mannose, glucose and galactose, but the molar ratios of monosaccharides were different. FT-IR spectra showed that CCp-1 and CCp-2 had the characteristic absorption of polysaccharides, and both had α-type and β-type glycosidic linkages. Triple helical structure and SEM analysis showed that CCp-1and CCp-2 had triple helix conformation and showed irregular porous lamellar structures. Besides, methylation and 1D/2D NMR analysis indicated that CCp-1 contained at least five linkages types, including1,5-linked-Araf, 1,2,4-linked-Rhaf, 1,6-linked-Galp, 1,4-linked-Xylp and 1,6-linked-Glcp. CCp-1 and CCp-2 could significantly shorten APTT, PT and TT to show procoagulant effect, which were related to activating the endogenous and exogenous coagulation pathways and thrombin activity. These results provided promising data indicating that the two polysaccharides isolated from C. chinensis flowers were effective coagulants.

Inhibiting the amyloid aggregation is considered to be an effective strategy to explore possible treatment of amyloid-related diseases including Alzheimer's disease, Parkinson's disease, and type II diabetes. Herein, a new high-efficiency and low-cytotoxicity Aβ aggregation inhibitors, GQD-T, was designed through the combination of two Aβ aggregation inhibitors, graphene quantum dots (GQDs) and tramiprosate. GQD-T showed the capability of efficiently inhibiting the aggregation of Aβ peptides and rescuing Aβ-induced cytotoxicity due to the synergistic effect of the GQDs and tramiprosate. In addition, the GQD-T has the characteristics of low toxicity and great biocompatibility. It is believed that GQD-T may be a potential candidate for an Alzheimer's drug and this work provides a new strategy for exploring Aβ peptide aggregation inhibitors.

Two-dimensional (2D) perovskite-type metal oxides with ultrathin feature of nanosheets are highly promising for electrochemical energy storage applications. Here, 2D perovskite LaNiO3 nanosheet assemblies with rich pores are prepared by facile sol-gel method and subsequent heating treatment. The crystal structure, morphology and electrochemical performance of LaNiO3can be simply tuned by adjusting the heating temperature and time. The optimized sample exhibited uniform sheet-like morphology with a thickness of ∼50 nm and a large surface area and pore volume, which achieves a high specific capacitance of 139.2 mAh g−1 at a current density of 1.0 A g−1, a good rate capability and an excellent cycle stability. What's more, the LaNiO3//graphene asymmetric supercapacitor device demonstrates a high energy density of 65.8 Wh kg−1 at a power density of 1.8 kW kg−1 and an outstanding cycling stability performance with 92.4% specific capacitance retention after 10000 cycles, which represents a critical step forward toward practical applications.

Phase-selective synthesis and structure switching behavior of a functional material are essential to enable comparative studies on the structure-property relationship. Here, we report a controllable fluorination route to phase-pure erbium oxyfluorides with orthorhombic (O-ErOF) and rhombohedral (R-ErOF) structures. This facile method adopts polytetrafluoroethylene (PTFE) as the fluridizer and the phase selectivity can be easily achieved at specific fluorination temperatures. The phase evolution and detailed crystal structures of erbium oxyfluoride were characterized by powder X-ray diffraction at various sintering temperatures and Rietveld refinements, respectively. An irreversible phase transition from O-ErOF to R-ErOF was observed under heating around 600 oC. The upconversion (UC) luminescence properties of R-ErOF and O-ErOF were studied comparatively by means of photoluminescence, P-I and UC decay curves. Despite their similar component and crystal structure, R-ErOF exhibits stronger (more than 20 times) red UC emission than O-ErOF. The anomalous UC behavior of the two polymorphisms of ErOF was associated with the energy transfer processes dependent on their crystal structure features.

Herein, considering the great potential of nitrogen-doped hierarchical porous carbons in energy storage and CO2 capture, we designed a convenient and easily large-scale production strategy for preparing nitrogen-doped hierarchical porous carbon sphere (NHPCS) materials. In this synthesis route, spherical resorcinol-formaldehyde (RF) resins were selected as carbon precursor, and then the ZnCl2-impregnated RF resin spheres were carbonized in a NH3 atmosphere at a temperature range of 600–800 °C. During the one-step heat-treatment process, nitrogen atom could be efficiently incorporated into the carbon skeleton, and the interconnected and hierarchical pore structure with different micro/mesopore proportion could be generated and tuned by adjusting the activating agent ZnCl2 dosage and carbonization temperature. The resultant nitrogen-doped hierarchical porous carbon sphere materials exhibited a satisfactory charge storage capacity, and the optimal sample of NHPCS-2-8 with a high mesopore proportion obtained at 800 °C with a ZnCl2/RF mass ratio of 2:1 presented a specific capacitance of 273.8 F g−1 at a current density of 0.5 A g−1. More importantly, the assembled NHPCS-2-8-based symmetric capacitor displayed a high energy density of 17.2 Wh kg−1 at a power density of 178.9 W kg−1 within a voltage window of 0 ∼ 1.8 V in 0.5 M Na2SO4 aqueous electrolyte. In addition, the CO2 capture application of these NHPCS materials was also explored, and the optimal sample of NHPCS-0-8 with a large micropore proportion prepared at 800 °C exhibited an exceptional CO2 uptake capacity at ambient pressures of up to 4.23 mmol g−1 at 0 °C.

Herein, we proposed a cost-efficient strategy to prepare nitrogen-doped porous graphitized carbon nanosheets, i.e. urea-assisted chemical blowing via foaming starch into the bubble networks of starch-derived polymers combining catalytic graphitization and subsequent KOH activation. In this synthesis route, starch acts as carbon precursor and foaming agent to build a bubble network of polymer, urea acts as nitrogen source and blowing agent to further blow bubble to form N-doped sheet-like carbons with ultrathin structure, γ-Fe 2 O 3 serves as a graphitization catalyst precursor to generate highly graphitized framework. Importantly, the thickness of sheets, the nitrogen content and the graphitization degree can be simply tuned by adjusting the mass ratio of urea/γ-Fe 2 O 3 /KOH. The optimal sample exhibited uniform sheet-like morphology with a thickness of ∼80 nm, a high surface area of 2129.8 m 2 g −1 , and a large pore volume of 0.97 cm 3 g −1 . Acting as an electrode for supercapacitor in 6 M KOH electrolyte, it presented a high specific capacitance of 337.6 F g −1 at 0.5 A g −1 . Moreover, the two-electrode symmetric cell was assembled in 1 M TEABF 4 /AN, and displayed a high energy density of 27.5 Wh kg −1 as well as an excellent cycling stability with 87.6% retention after 5000 cycles.

Nitrogen doping via high-temperature ammonization is a frequently used strategy to extend the light harvesting capacity of wide-bandgap catalysts in the visible region. Under such a reductive atmosphere, the reduction of transition metals is supposed to occur, however, this has not been thoroughly studied yet. Here, by combining chemically-controlled doping and subsequent liquid exfoliation, ultra-thin [Nb3O8]- nanosheets with separate N doping, reduced-Nb doping and N/reduced-Nb codoping were fabricated for comparative studies on the doping effect for photocatalytic hydrogen evolution. Layered KNb3O8 was used as the starting material and the above-mentioned three doping conditions were achieved by high-temperature treatment with urea, hydrogen and ammonia, respectively. The morphology, crystal and electronic structures, and the catalytic activity of the products were characterized thoroughly by means of TEM, AFM, XRD, XPS, EPR, absorption spectroscopy and photocatalytic hydrogen evolution. Significantly, the black N/reduced-Nb co-doped monolayer [Nb3O8]- nanosheets exhibit the mostly enhanced photocatalytic hydrogen generation rate, indicating a synergistic doping effect of the multiple chemical-design strategy. The modified electronic structure of [Nb3O8]- nanosheets and the role of exotic dopants in bandgap narrowing are put forward for the rational design of better photocatalysts with reduced-metal self-doping.

Many novel two-dimensional (2D) allotropes of carbon have been predicted to be (meta)stable at 0 K, however, their thermal stability and mechanical properties at finite temperatures remain unclear. In this study, the mechanical properties and fracture behaviors of five newly predicted monatomic thick carbon sheets (C 31 , C 33 , δ-graphyne (GY), γ-GY, C 63 , and graphene) are investigated using molecular simulations. The δ-GY, γ-GY, and graphene show brittle fractures in uniaxial tension testing at temperatures from 1 to 1200 K. The first signs of fracture in these brittle carbon sheets indicate that the C C bonds linking the benzene rings and linear acetylenic carbons break with strong directional preference, whereby the direction of the breaking C C bonds is parallel to the direction of tensile stress. A brittle-to-ductile transition is identified in the C 31 , C 33 , and C 63 sheets at high temperatures, which corresponds to the breakages of the C C bonds in the triangular carbon rings. Global and local order-order structural transitions as well as order-disorder transitions are obtained in different ductile carbon sheets, and are found in the same carbon sheet under tensile stress along different directions. These results suggest a strong correlation between the structure and the failure mechanism in 2D carbon sheets, which is of great importance in the future design, synthesis and application of novel 2D materials.

Recently, a new carbon sheet, phagraphene, was proposed by theoretical calculations [Nano Lett. 2015, 15, 6182]. In this paper, hydrogenated and fluorinated phagraphene (denoted as H-PHA and F-PHA) sheets have been systematically studied using first-principles calculations. The results of formation energy, ab initio molecular dynamics, phonon dispersion and elastic constants confirm that the modified phagraphene sheets are thermodynamically and dynamically as well as mechanically stable. We find that hydrogenation or fluorination is an effective way to modulate the bandgap, and we also find that adsorption-induced semimetal-semiconductor transition and adsorption-induced semimetal-insulator transition occur. Configuration-dependent bandgaps for partially H-PHA and configuration-independent bandgaps for fully H-PHA are determined. Adsorption-ratio-dependent bandgaps of H-PHA and F-PHA are also identified. Bandgaps calculated from HSE06 and PBE functionals of fully H-PHA are larger than those of F-PHA, and they are comparable to hydrogenated/fluorinated penta-graphene while they are larger than their corresponding graphene. Dependence of bandgaps of fully H-PHA and F-PHA on the tensile strain is investigated, and our calculations show that an insulator-semiconductor transition occurs upon increasing the tensile strain. Our results also show that the mechanical properties can be controlled using hydrogenation and fluorination. The calculations of Young's modulus and Poisson's ratio reveal that functionalized phagraphene sheets possess suitable stiffness and resistance to volume deformation, and both are smaller than those of the pristine phagraphene.

Repeated traumatic brain injury, leads to cumulative neuronal injury and neurological impairments. There are currently no effective treatments to prevent these consequences. Growing interest is building in the use of transcranial photobiomodulation (PBM) therapy to treat traumatic brain injury. Here, we examined PBM in a repeated closed head injury (rCHI) rat model. Rats were administered a total of three closed head injuries, with each injury separated by 5 days. PBM treatment was initiated 2 hours after the first injury and administered daily for a total of 15 days. We found that PBM-treated rCHI rats had a significant reduction in motor ability, anxiety and cognitive deficits compared to CHI group. PBM group showed an increase of synaptic proteins and surviving neurons, along with a reduction in reactive gliosis and neuronal injury. These findings highlight the complexity of gliosis and neuronal injury following rCHI and suggest that PBM may be a viable treatment option to mitigate these effects and their detrimental consequences.

The development of efficient nanomedicines to improve anticancer therapeutic effects is highly attractive. In this work, we firstly report titania-coated Au nanoplate (Au NPL@TiO2) heterostructures, which play dual roles as nanoagents for synergistic photothermal/sonodynamic therapy in the second near-infrared (NIR) window. On the one hand, because the controlled TiO2 shells endow the Au NPL@TiO2 nanostructures with a red shift to the NIR II region, the as-prepared Au NPL@TiO2 nanostructures possess a high photothermal conversion efficiency of 42.05% when irradiated by a 1064 nm laser and are anticipated to be very promising candidates as photothermal agents. On the other hand, the Au nanoplates (Au NPLs), as electron traps, vastly improve the generation of reactive oxygen species (ROS) by the Au NPL@TiO2 nanostructures in contrast with pure TiO2 shell nanoparticles upon activation by ultrasound (US) via a sonodynamic process. Moreover, the toxicity and therapeutic effect of the Au NPL@TiO2 nanostructures were relatively systemically evaluated in vitro. The Au NPL@TiO2 nanostructures generate a large amount of intracellular ROS and exhibit laser power density-dependent toxicity, which eventually induces apoptosis of cancer cells. Furthermore, a synergistic therapeutic effect, with a cell viability of only 20.3% upon both photothermal and sonodynamic activation, was achieved at low concentrations of the Au NPL@TiO2 nanostructures. Experiments on mice also demonstrate the superiority of the combination of PTT and SDT, with the total elimination of tumors. This work provides a way of applying two-dimensional (2D) gold nanoplate core/TiO2 shell nanostructures as novel nanoagents for advanced multifunctional anticancer therapies in the second NIR window.

As an emerging technique for rapid detection, Surface-enhanced Raman scattering (SERS) has received much practical attention. Here, we report a uniformly distributed silver nanoparticles on well-defined tungsten oxide nanoflakes hierarchical nanostructures (Ag/WO3-x) as flexible solid SERS substrate. The vertically aligned Ag/WO3-x nanoflakes were prepared by in situ redox reaction without reductant additives, ensuring the clean surface and free of extra interferences with good signal-to-noise ratio. Using rhodamine 6G (R6G) as probe molecule, the enhancement factor of developed Ag/WO3-x nanoflakes SERS substrate was found to be high as 2.41 × 107 with an ultrasensitive detection concentration of 10-12 M. Additionally, Ag/WO3-x nanoflakes SERS substrate exhibited good reproducibility and long-time stability. Meanwhile, the pesticide thiram with a 1.3 pM limit of detection (LOD) can be readily determined via developed SERS substrate. To illustrate the potential practical value of the prepared substrates, 2.4 ppb spiked thiram on apple peel surface were both successfully detected. Notably, the developed SERS substrates could be cut into small pieces for detecting trace chemical or biological molecules and the flexible utilization of substrates would be improved dramatically. As a result, vertically aligned Ag/WO3-x nanoflakes with well-defined shape and hierarchical structure have great potential as solid SERS substrate in the field of fast detection and trace analysis.

The ethyl acetate extract of Amygdalus persica L. flowers (family Rosaceae) was fractionated by silica gel and Sephadex LH-20 column chromatography, and, after recrystallization, oleanolic acid (1), ursolic acid (2), quercetin (3), kaempferol (4), hesperetin (5), naringenin (6), and kaempferol-3- O-glucoside (7) were isolated. Their identities were elucidated by spectral techniques and from their physicochemical properties. Compounds 3-7 were identified from A. persica flowers for the first time. All the compounds were evaluated for their procoagulant activity by determining their activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), and fibrinogen (FIB) in vitro. The coagulation activity results showed that oleanolic acid and ursolic acid could significantly prolong APTT and TT; quercetin could significantly shorten PT and TT; kaempferol and hesperetin could significantly shorten APTT, PT, and TT; and naringenin could significantly shorten APTT, PT, and TT and decrease the content of FIB compared with the blank group. All of the above revealed that quercetin, kaempferol, hesperetin and naringenin possessed significant procoagulant activity, while ursolic acid had anticoagulant activity in vitro.