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Plasmonic nanovesicles show broad applications in areas such as cancer theranostics and drug delivery, but the preparation of nanovesicles from shaped nanoparticles remains challenging. This article describes the vesicular self-assembly of shaped nanoparticles, such as gold nanocubes grafted with amphiphilic block copolymers, in selective solvents. The nanocubes assembled within the vesicular membranes exhibit two distinctive packing modes, namely square-like and hexagonal packing, depending on the relative dimensions of the copolymer ligands and nanocubes. The corresponding optical properties of the plasmonic nanovesicles can be tuned by varying the length of the grafted copolymers and the size of the nanocubes. This work provides guidance for the fabrication of functional plasmonic vesicles for applications in catalysis, nanomedicines and optical devices.

As competitive photocatalysts, Cu2O nanoparticles meet with severe photogenerated carries recombination and insufficient light absorption, leading to the poor photocatalytic performance. Herein, the truncated Cu2O-Au (CA) binary and Cu2O-Au-TiO2 (CAT) ternary octahedra with Au nanoparticles (Au NPs), preferentially supported on the (110) and (100) planes of Cu2O, are synthesized for efficient photocatalytic degradation reactions. The photodegradation rates of MO of CA1 (Cu2O-Au containing 1 wt % Au) and CAT are as high as 95.61% and 96.5% under 60 min of visible light irradiation, respectively. On the one hand, the synergistic function of localized surface plasmon resonance (LSPR) of Au NPs and Schottky barrier accelerate the separation and transfer of photogenerated carriers. On the other hand, a Z-scheme electron transfer system is constructed in CAT to promote the photodegradation performance. According to the finite-difference-time-domain (FDTD) simulation result, there is a strong electric field enhancement at the contact sites between Au, Cu2O and TiO2, which accelerates the electron transfer to a large extent and separates the electron-hole pairs. Therefore, this work may provide an approach for the synthesis and applications of multiple heterostructure catalyst.

Hydrogen emerges as alternative green energy, replacing fossil fuels due to its high gravimetric energy density, pollution free, efficiency, and renewability. Ammonia borane (AB) possessing high hydrogen density (19.6 wt.%)...

Superelectrophilic monoanions [B12 (BO)11 ]- and [B12 (OBO)11 ]- , generated from stable dianions [B12 (BO)12 ]2- and [B12 (OBO)12 ]2- , show great potential for binding with noble gases (Ngs). The binding energies, quantum theory of atoms in molecules (QTAIM), natural population analysis (NPA), energy decomposition analysis (EDA), and electron localization function (ELF) were carried out to understand the B-Ng bond in [B12 (BO)11 Ng]- and [B12 (OBO)11 Ng]- . The calculated results reveal that heavier noble gases (Ar, Kr, and Xe) bind covalently with both [B12 (BO)11 ]- and [B12 (OBO)11 ]- with large binding energies, making them potentially feasible to be synthesized. Only [B12 (OBO)11 ]- could form a covalent bond with helium or neon but the small binding energy of [B12 (OBO)11 He]- may pose a challenge for its experimental detection.

The development of vacuum circuit breaker (VCB) toward large current and high voltage is extremely limited with contact material. Herein, a new type of VCB contact model including microstructure is proposed. Emerging contact material achieves the breakthrough from external applying to self-excited magnetic field, besides strong magnetic strength and low temperature rise. Three-dimensional finite-element simulations, which contain microcoil, unit groups, and coupled contacts, were implemented. And the influence factors involve eddy current losses, iron core diameter, units’ spacing, and copper–chromium layer thickness. Simulation results indicate that the magnetic field is the most efficient when the distance between the coupled coils is 1.65 mm and the thickness of the Cu–Cr layer is 3 mm. Moreover, the relative practical models and measures were carried out to verify the distribution of magnetic field, and the results were in good agreement with theoretical predictions. Therefore, the theoretical data can guide the design of practical contact models and support the optimization of structural parameters, applied to vacuum interrupter.

First-principles calculations have been carried out for the 20-electron transition metal complexes (Cp)2TMO and their molecular wires (Cp = C5H5, C5(CH3)H4, C5(CH3)5; TM = Cr, Mo, W). The calculation results at the BP86/def2-TZVPP level reveal that the ground state is singlet and the optimized geometries are in good agreement with the experimental values. The analysis of frontier molecular orbitals shows that two electrons in the highest occupied molecular orbital HOMO-1 are mainly localized on cyclopentadienyl and oxygen ligands. Furthermore, the nature of the TM-O bond was investigated with the energy decomposition analysis-natural orbitals for chemical valence (EDA-NOCV). The attraction term in the intrinsic interaction energies ΔEint is mainly composed of two important parts, including electrostatic interaction (about 52% of the total attractive interactions ΔEelstat + ΔEorb) and orbital interaction, which might be the major determinant of the stability of these (Cp)2TMO complexes. All of the TM-O bonds should be described as electron-sharing σ single bonds [(Cp)2TM]+-[O]- with the contribution of 53-57% of ΔEorb and two π backdonations from the occupied p orbitals of oxygen ligands into vacant π* MOs of the [(Cp)2TM]+ fragments, which are 35-40% of ΔEorb. The results of bond order and interaction energy from EDA-NOCV calculations suggest the influence of the radius of TM and methyl in the interactions between TM and O in (Cp)2TMO. Additionally, the relativistic effects slightly amplify the strength of bonding with increasing ΔEorb for the EDA-NOCV calculations on three metal complexes (C5H5)2TMO. Finally, the geometries, electronic structures, and magnetics of infinitely extended systems, [(C5H5)TMO]∞, have also been explored. The results of the density of states (DOS) and band structure revealed that [(C5H5)CrO]∞ and [(C5H5)WO]∞ are semiconductors with the narrow bands, whereas [(C5H5)MoO]∞ behaves as metal.

Ligand engineering based on a closo-B12-cage has been practiced in this work to design a series of stable gas-phase dianions [B12(ECX)12]2− (E = N, P, and As; X = O, S, and Se) via ab initio calculations. The calculated second electron affinities ranging from 1.2 to 3.4 eV indicate that these dianions are electronically stable against electron auto-detachment. Their electronic structures were analyzed based on molecular orbitals and natural bond orbitals. We found that in these designer dianions, the ECX ligands bind the B12-cage via B–E covalent interactions. We simulated the photoelectron spectra of these dianions and discussed the potential application of [B12(NCX)12]2− (X = O, S, and Se) salts as electrolytes in Li- or Mg-ion batteries.

Endohedral group14-based clusters with the encapsulation of a transition metal, which are termed [TM@Em]n− (TM = transition metal and E = group-14 elements), have lots of potential applications and have been used as interesting building blocks in materials science. Nevertheless, their electronic structures and stability mechanism remain unclear. In this paper, we systematically study the geometries, electronic structures, and bonding properties of [TM@E9]n− clusters which are the smallest endohedral group-14-based clusters synthesized so far, by using density functional theory (DFT) calculations. The calculation results reveal the important role of TMs in affecting the structures and bonding interactions in the [TM@E9]n− cluster. In the presence of a TM, the cluster geometry could change from a monocapped square antiprism (C4v) for empty [E9]4− cages to a tricapped trigonal prismatic geometry (D3h) for [TM@E9]n−. By using the energy decomposition analysis (EDA) method, the bonding properties between the endohedral TM and E9 cluster have been thoroughly investigated. It was found that the origin of stability of these clusters is from the large electrostatic attraction with significantly reduced Pauli repulsion. In the case of orbital interactions, the π back-donations from d orbitals of the TM to the cluster make important contributions. More interestingly, the 1D-chain and 2D-sheet nanostructures based on the [Ni@E9] cluster have been theoretically predicted. The band structure and density of states analysis revealed that all of these nanostructures are metallic and their excellent thermodynamic stability has been confirmed by using ab initio molecular dynamics (AIMD) simulations.

The coordination of 10-electron diatomic ligands (BF, CO N2) to iron complexes Fe(CO)2(CNArTripp2)2 [ArTripp2=2,6-(2,4,6-(iso-propyl)3C6H2)2C6H3] have been realized in experiments very recently (Science, 2019, 363, 1203-1205). Herein, the stability, electronic structures, and bonding properties of (E1E2)Fe-(CO)2(CNArTripp2)2 (E1E2=BF, CO, N2, CN-, NO+) were studied using density functional (DFT) calculations. The ground state of all those molecules is singlet and the calculated geometries are in excellent agreement with the experimental values. The natural bond orbital analysis revealed that Fe is negatively charged while E1 possesses positive charges. By employing the energy decomposition analysis, the bonding nature of the E2E1-Fe(CO)2(CNArTripp2)2 bond was disclosed to be the classic dative bond E2E1→Fe(CO)2(CNArTripp2)2 rather than the electron-sharing double bond. More interestingly, the bonding strength between BF and Fe(CO)2(CNArTripp2)2 is much stronger than that between CO (or N2) and Fe(CO)2(CNArTripp2)2, which is ascribed to the better σ-donation and π back-donations. However, the orbital interactions in CN-→Fe(CO)2(CNArTripp2)2 and NO+→Fe(CO)2(CNArTripp2)2 mainly come from σ-donation and π back-donation, respectively. The different contributions from σ donation and π donation for different ligands can be well explained by using the energy levels of E1E2 and Fe(CO)2(CNArTripp2)2 fragments.

Lithium-sulfur batteries with high-energy density are witnessed to be the most prospective next generation advanced batteries. Nonetheless, the existing issues of serious shuttle effect and insulat...

Designing highly active material to fabricate high-performance glucose sensor was great importance for diabetes treatment. In this work, we develop a novel nanocomposite composed of multilevel nanostructure with ultrathin CuxO nanoflakes anchored on Cu2O nanowires, directly on Cu foil and its application as non-enzymatic glucose sensor. Due to more active sites endowed by the ultrathin CuxO nanoflakes, the as-prepared CuxO nanoflakes/Cu2O nanowires@Cu nanoarray exhibit high sensitivity (3.59 mA mM−1 cm−2), low detection limit (0.69 μM), high selectivity, fast amperometric response (~ 2 s) and excellent reliability in human serum. And the sensitivity of ultrathin CuxO nanoflakes/Cu2O nanowires@Cu nanoarray was 1.9-fold than that of Cu2O nanowires@Cu nanoarray. Such novel multilevel nanoarray synthesized by convenient method provides a facile way to design metal oxide nanomaterial for promising non-enzymatic glucose sensor.

A rhombicuboctahedral (26-facet) Cu2O single crystal, generally with well-developed {100}, {110} and {111} crystallographic planes, has attracted considerable attention due to its faceted synergistic effects in catalysis, sensing, and energy conversion. However, the electrocatalytic performance of the 26-facet Cu2O single crystal can be severely limited by its large size and low-active smooth surface, since it is quite difficult to prepare high-active 26-facet Cu2O nanocrystals exposed with rough surfaces. In this article, we successfully prepared jagged 26-facet Cu2O nanocrystals with clean facets at room temperature via a facile Mn2+ mediated aqueous phase reduction method. The shape-evolution and growth mechanism of rhombicuboctahedral Cu2O nanocrystals enclosed by jagged surfaces are also proposed, which might be attributed to a sequential dissolution–precipitation–surface reforming mechanism. These unique jagged 26-facet nanocrystals exposed with more active sites can exhibit superior glucose-sensing performance than those of the traditional 26-facet Cu2O microcrystals enclosed by smooth surfaces. With the merits of facile control as well as relatively high activity, it could provide a good prospect for the surfactant-free synthesis of other metal oxides with well-defined crystal planes.

The reaction mechanism, ligand and norbornene effects, and origins of meta-selectivity in Pd/norbornene-catalyzed alkylation and arylation via C–H activation are theoretically elucidated by DFT computation. The reaction proceeds through six major steps: ortho-C–H activation, norbornene insertion into Pd–C bonds, meta-C–H activation, meta-C–C bond formation, β-carbon elimination, and protodemetallation. Both ortho-C–H and meta-C–H activations undergo a concerted metalation–deprotonation pathway. The meta-C–C bond formation, which is the selectivity-determining step, follows a Pd(IV) pathway via oxidative addition on a Pd(II) five-membered-ring intermediate. The oxidative addition of alkyl iodide adopts an SN2 pathway, whereas aryl iodide prefers concerted oxidative addition rather than the SN2 pathway. The Pd(II) pathway via meta-C–C reductive coupling on dinuclear palladium species is not the dominant pathway because of the low concentration of Pd(0)L2. For methylation, with norbornene and pyridine (or its derivative) as ligands, the C–C reductive coupling and C–C reductive elimination from the Pd(IV) intermediate are found to be the selectivity-determining steps for meta-functionalization and benzocyclobutene formation, respectively, whereas the use of large ligands such as acridine and quinoline-type ligands (L1 and L2) moves the selectivity-determining step back to the oxidative addition and the C–C reductive elimination steps on the Pd(II) intermediate. The geometric and electronic properties of L1 and L2 further suppress the benzocyclobutene formation by increasing the energy difference between meta-functionalization and benzocyclobutene formation. The combination of 2-carbomethoxynorbornene and L2 promotes meta-ethylation and -arylation by disfavoring the C–C reductive elimination steps from the Pd(II) and Pd(IV) intermediates as well as slightly favoring the oxidative addition step.

Supported noble metal catalysts have exhibited satisfactory catalytic performance in the dehydrogenation of liquid chemical hydrogen carriers, in which the supports play a paramount role in conditioning the nature of the active center and thus improving the overall reactivity. Herein, the specially designed nitrogen/amino co-functionalized carbon (NH2-NC) supports are prepared to load active Pd nanoclusters for efficient dehydrogenation of formic acid (FA). The nitrogen/amino co-functionalization of carbon not only facilitates the Pd nanoclusters evenly dispersed with a mean size of 1.4 nm, but also provides a beneficial metal-support interaction to promote FA dehydrogenation. The as-prepared Pd@NH2-NC discloses a 100% conversion of FA into CO2 and H2 with a remarkable initial turnover frequency (TOFinitial) of 4,892 h-1 and a low activation energy (Ea) of 28.5 kJ mol-1 without additive at 298 K. The work proposes a co-functionalization strategy to reasonably design supports for heterogeneous catalysts and may be extended to develop other multi-functionalized supports with different compositions and nanostructures.

Endohedral group14-based clusters with the encapsulation of a transition metal, which are termed [TM@E

High-performance, nonprecious metal catalysts with special morphologies and easy-to-recycle properties are essential for the treatment of environmental pollutants. Herein, CoFe nanoparticle-decorated reduced graphene oxide (RGO) catalysts were designed and successfully fabricated, and the catalyst was then used to reduce 4-nitrophenol into 4-aminophenol. Outstanding catalytic properties with a reduction rate constant of 4.613 min-1 were achieved due to the synergistic properties of the CoFe metal alloy and the high-conductivity RGO components in the catalysts. In addition, the catalyst was conveniently recovered via magnets due to its inherent magnetic properties. The facile preparation, outstanding catalytic performance, structural stability, and low material costs make the CoFe/RGO nanocatalyst a promising candidate for potential applications in catalysis.

Superelectrophilic monoanions [B

Novel electronic donor with polycyclic structure based on coumarin was designed and prepared. Pyrrolidine acting as an isolated group was introduced to the donor by the Buchwald-Hartwig amination reaction. Such a novel electronic donor demonstrated great electron-donating capability and an excellent isolation effect. Both chromophores exhibited a D-π-A-π-A molecular structure. Such a structure has great advantages in energy matching, dipole interaction, and electron transfer, compared to the single D-π-A structure. The chemical structures of novel chromophores based on this donor were characterized by 1H nuclear magnetic resonance spectroscopy, 13C nuclear magnetic resonance spectroscopy, and mass spectrometry. The largest electro-optic coefficients are approximately 31.2 and 42.6 pm/V for chromophores NLO-C and NLO-P, respectively, at 1310 nm; otherwise, both chromophores NLO-C and NLO-P exhibit high thermal decomposition temperatures, i.e., 276 and 237 °C, respectively.

Two-dimensional (2D) nanocomposites, based on graphene and transition metal oxides, hold great promise as high-performance electrode materials for next-generation lithium-ion batteries. Herein, a novel 2D CuO/RGO has been constructed by CuO ultrathin nanosheets and reduced graphene oxides (RGO) through in-situ oxidizing the Cu/RGO nanocomposite with hydrogen peroxide. CuO nanosheets with a thickness of 1.17–1.57 nm are uniformly and tightly anchored on the RGO surface without aggregation and thus the as-prepared CuO/RGO nanosheets electrode show strong interfacial coupling and fast electron transfer. Electrochemical characterizations reveal that the CuO/RGO nanocomposite electrode exhibits a remarkably enhanced cycling performance and rate performance. At the current density of 0.1C, the initial discharge capacity of 811 mAh/g has been delivered by CuO/RGO nanosheets electrode and the coulombic efficiency maintains 99.44% after 100 cycles. Moreover, the CuO/RGO nanosheets exhibit a stable specific capacity of 386 mAh/g after 200 cycles at 3C. In addition, the as-prepared CuO/RGO nanocomposite electrode exhibited excellent rate performance and lower charge transfer resistance. The current study presents a feasible route to fabricate nanosheets electrode materials for next-generation energy storage devices.

(1-x)(0.72Bi0.5Na0.5TiO3-0.28SrTiO3)-xBiAlO3 (BNT-ST-xBA) lead-free ceramics were prepared through solid-state sintering methods. The structural, dielectric and energy storage properties of the cer ...

A stable and highly sensitive graphene/hydrogel strain sensor is designed by introducing glycerol as a co-solvent in the formation of a hydrogel substrate and then casting a graphene solution onto the hydrogel in a simple, two-step method. This hydrogel-based strain sensor can effectively retain water in the polymer network due to the formation of strong hydrogen bonding between glycerol and water. The addition of glycerol not only enhances the stability of the hydrogel over a wider temperature range, but also increases the stretchability of the hydrogel from 800% to 2000%. The enhanced sensitivity can be attributed to the graphene film, whereby the graphene flakes redistribute to optimize the contact area under different strains. The careful design enables this sensor to be used in both stretching and bending modes. As a demonstration, the as-prepared strain sensor was applied to sense the movement of finger knuckles. Given the outstanding performance of this wearable sensor, together with the proposed scalable fabrication method, this stable and sensitive hydrogel strain sensor is considered to have great potential in the field of wearable sensors.

Ultrafine Ag nanoparticles with unique physicochemical properties have a wide potential catalytic application. Herein, a one-pot method based on UV irradiation was applied for the synthesis of Ag-hydrogel composite, in which ultrafine Ag nanoparticles with a mean size of 2.47 ± 0.26 nm were well dispersed in the hydrogel network. In addition, the as-prepared Ag-hydrogel composites showed great catalytic performance and stability in the reduction of 4-nitrophenol.

The application of templating and etching agents for the synthesis of mesoporous graphitic carbon nitride (mpg-C3N4) is not environmentally friendly, motivating attempts to develop a green and efficient strategy to construct mpg-C3N4 with improved photocatalytic performance. Herein, for the first time, we demonstrate a general carbonated beverage-assisted hydrothermally-reformed commercial melamine (MA) strategy for the synthesis of mpg-C3N4 nanosheets. Although the dosage of carbonated beverage (including Coca-Cola, Pepsi-Cola, Sprite and Fanta) is very small for the modification of MA precursors, the improvement in the photocatalytic activity of the mpg-C3N4 products is very remarkable. With the unique structural advantages for aligned energy bands and charge carrier migration, and numerous photocatalytic sites, the visible-light-driven photocatalytic hydrogen evolution rate (HER) of mpg-C3N4 nanosheets synthesized from a Coca-Cola-reformed MA precursor is 15.1 times higher than that of bulk g-C3N4, achieving an apparent quantum yield of 7.7% at 420 nm. Similarly, mpg-C3N4 nanosheets synthesized from Pepsi-Cola-, Sprite- and Fanta-reformed MA precursors also exhibit enhanced photocatalytic HERs.

Doping and exfoliation are effective strategies to improve the photocatalytic activity of bulk graphitic carbon nitride (g-C3N4). Therefore, it can be inferred that engineering element-doping and exfoliation into g-C3N4 would further enhance the photocatalytic performance. Herein, we demonstrated a KOH-assisted hydrothermal-reformed melamine strategy for achieving the simultaneous K-doping and exfoliation of g-C3N4. The as-synthesized K-doped g-C3N4 ultrathin nanosheets displayed much enhanced photocatalytic hydrogen evolution rate (HER) of about 13.1 times higher than that of the bulk g-C3N4 under visible-light irradiation, achieving an apparent quantum efficiency of 6.98% at 420 nm. The improved photocatalytic HER can be attributed to the high surface area offering numerous photocatalytic active sites, enlarged conductive band edge optimizing photoreduction potential, and K-doping promoting charge generation and separation as well as the long life-time of photogenerated carriers. This work would provide a promising way to integrate co-doping and exfoliation into new g C3N4 based materials.

A systematic first-principles study is performed to investigate the 20-electron transition metal complexes (CH)TM(EE) (TM = Cr, Mo, W; EE = CO, N, BF). The bond dissociation energy (De) based on (CH)TM(EE) → (CH)TM(EE) + EE indicates much lower thermodynamic stability of (CH)TM(N) because of poor binding ability of N ligands. For the thermodynamic stable (CH)TM(EE) complexes (TM = Cr, Mo, W; EE = CO, BF), their 20-electron nature is derived from their occupied nonbonding molecular orbital mainly donated by ligands. Furthermore, charge transfer from TMs to the CH ligands is revealed by the atoms in molecules (AIM) theory, leading to the positive charges of the TM atoms. On the other hand, the nature of the TM-E bond has been thoroughly analyzed by the energy decomposition analysis (EDA) method. The absolute value of interaction energies (|ΔE|) between (CH)TM(EE) and EE has the same trend as the corresponding bond dissociation energy and Wiberg bond orders of TM-E bonds, following the order W > Mo > Cr with same ligands and BF > CO with same TM. Additionally, the largest contribution to the ΔE values is the repulsive term ΔE. Similar contributions from covalent and electrostatic terms to the TM-E bonds were found, which can be described as the classic dative bond with nearly same σ and π contributions. The stronger σ donations and π backdonations in (CH)TM(BF) than in (CH)TM(CO) indicate much more stability of (CH)TM(BF).

First-principles calculations have been carried out for the 20-electron transition metal complexes (Cp)