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Two polyoxometalate-based hybrids, [M(btap)3(H2O)3(HPW12O40)]·xH2O (M-PW, M = Co/Mn, btap = 3,5-bis(1′,2′,4′-triazol-1′-yl)pyridine) were synthesized. Co-PW exhibited higher activity and selectivity towards olefin epoxidation than Mn-PW due to the synergistic effect between CoII and PW, in which the Co centers activate O2 to ˙O2− and further binding of free H+ from PW affords the active peroxyacid. [ABSTRACT FROM AUTHOR]

Due to the small hydrated ionic radius and light molar mass of ammonium ions, aqueous ammonium ion batteries attract much attention, providing high security, environmental friendliness and low cost. However, the lack of suitable electrode materials with high specific capacity is a big challenge for practical application. Therefore, in view of this problem, we fabricated an anode applying a MoS2 material with a ball-flower morphology anchored to MXene nanoflakes, and it shows excellent rate capability in a novel aqueous ammonium ion battery. The corresponding charge capacities of composite electrodes are 279.2, 204.4, 173.2, 118.7, and 80.5 mA h g−1 at 20, 50, 100, 200, and 500 mA g−1, respectively. Meanwhile, polyvanadate was selected as a cathode material for a full aqueous ammonium ion battery, and interestingly it was discovered that the size of this material decreases with increasing synthesis temperature. The discharge capacities of NH4V4O10 electrodes fabricated at 140 °C, 160 °C, and 180 °C at 50 mA g−1 are 88.6, 125.1 and 155.5 mA h g−1, respectively. Furthermore, we also explore the corresponding electrochemical mechanism using XRD and XPS. A full aqueous ammonium ion battery based on both electrodes shows superior ammonium ion storage properties and provides new ideas for the development of this strategy. [ABSTRACT FROM AUTHOR]

Carbon nanohoop compounds have attracted extensive attention recently due to their aesthetically pleasing structures and unique properties. In order to reveal the structure–property relationship between the size-dependent effect and the nonlinear optical (NLO) response, a series of carbon nanohoops consisting of zigzag carbon nanotubes (CNTs), named D-CM2PnP-A (n = 4, 6, 8, 10, and 12), are systematically designed and investigated using density functional theory (DFT). Significantly, the first hyperpolarizability (βtot) of the system increases with the increasing structure size, which is primarily the result of the charge transfer transition. Subsequently, the major electronic transition changes from local excitation to charge transfer as the size of the structure increases, indicating that charge transfer becomes stronger significantly. Furthermore, a two-level model and the absorption spectrum can well explain the trend of the βtot value. In addition, the unit sphere representation (USR) and hyper-Rayleigh scattering (HRS) are used to further explain the nature of the second-order NLO response. More importantly, adding a π-bridge as an effective strategy further enhances the second-order NLO responses of the system. The relevant results are expected to provide a new perspective on the structure–NLO property correlation of donor (D)–conjugated bridge (π)–acceptor (A) type carbon nanohoops and theoretical guidance for the rational design and synthesis of fascinating carbon nanohoops as NLO materials. [ABSTRACT FROM AUTHOR]

In a variety of skeletal structures of delayed fluorescence molecular materials, the donor–acceptor–donor (D–A–D) type has been widely considered for improving the efficiency of the reverse intersystem crossing (RISC) process. Herein, three new D–A–D molecules (PTZ-MPS, TPA-MPS and PCz-MPS) bearing 9,9-dimethylthioxanthene-S,S-sulfur dioxide (MPS) as the electron acceptor group are designed and investigated using theoretical calculations. PTZ-MPS shows the feature of the high-lying reverse intersystem crossing process, which is conducive to improving the exciton utilization of organic light-emitting diodes (OLEDs). PTZ-MPS has a much smaller singlet–triplet energy splitting (ΔES1T3 = 0.03 eV) than TPA-MPS (ΔES1T3 = 0.32 eV) and PCz-MPS (ΔES1T3 = 0.59 eV). However, it has a much larger spin–orbital coupling (SOC) strength (〈S1‖ĤSOC‖T3〉 = 1.013 cm−1) than TPA-MPS (〈S1‖ĤSOC‖T3〉 = 0.311 cm−1) and PCz-MPS (〈S1‖ĤSOC‖T3〉 = 0.354 cm−1), which makes it easy to induce a sufficient RISC from the Tn state to the S1 state. The ΔEST and SOC are the two most important factors in determining TADF molecules. Therefore, PTZ-MPS is expected to be a potential high-lying excited state delayed fluorescence material candidate, and our work demonstrates that high-performance TADF materials can also be obtained successfully by designing rational molecules. [ABSTRACT FROM AUTHOR]

Quantitative in situ elemental analyses of the impure deposited layer on the plasma-facing components (PFCs) of magnetically confined fusion devices such as EAST are crucial and challenging. Laser-induced breakdown spectroscopy (LIBS) is one of the most promising methods. In this study, we present an improved quantitative analytic algorithm for the deposited layers (in vacuum) of both major and minor elements via one-point calibration laser-induced breakdown spectroscopy (OPC-LIBS). OPC-LIBS is a variation of the calibration-free LIBS approach involving one matrix-matched standard sample with a known composition that effectively corrects the errors, caused by the uncertainty of Einstein's coefficient and inaccurate efficiency of the spectrum acquisition system of the CF-LIBS method. We found that the OPC-LIBS method is more accurate for the determination of composition of a series of Al–W–Mo coatings (EAST-like deposits) compared to the conventional CF-LIBS approach at 10−5 mbar to simulate the pressure condition of a fusion vessel. In the case of OPC-LIBS measurement, the relative error of major elements such as Al (85.65–95.51 at%) was below 2%, and the relative error of trace elements W (2.32–9.56 at%) was within 35% and Mo (2.17–11.66 at%) was within 20%. Finally, our results verify the ability of quantitative analysis by using the OPC method in a high-vacuum environment and film samples. [ABSTRACT FROM AUTHOR]

Cu-Based quantum dots (QDs) are of great interest due to their unique properties enabling the replacement of traditional toxic Cd- or Pb-based QDs, for use in bioimaging and biomedical applications. Different reaction conditions have profound effects upon the morphologies and photophysical properties of the obtained QDs, the investigation of which is crucial in order to prepare the highest quality Cu-based QDs. Here, we have carried out a series of studies, optimizing the synthesis of CIZS/ZnS/ZnS QDs via careful control of the ZnS shell deposition. The effects of different reaction temperatures and growth times on the resulting morphologies and optical properties of the QDs have been systematically examined. It has been found that reaction temperature plays a significant role in the resulting optical properties and morphologies, affecting the deposition dynamics of the shell materials and the onset of severe surface ligand degradation. Based on the detailed studies, optimal reaction conditions have been chosen and highly fluorescent CIZS/ZnS/ZnS core/shell/shell heterostructured QDs, with PLQYs as high as 41.6 ± 4.2%, have been produced. In addition, we have achieved for the first time a "giant" ZnS shell (QDs of 13.02 nm in diameter). These results are important for the further development of CIZS/ZnS/ZnS core/shell/shell nanoheterostructures with optimal optical properties and morphology. [ABSTRACT FROM AUTHOR]

A porous Cu2O/TiO2 hybrid photocatalyst with n-type Cu2O decorated on the mesoporous TiO2 derived from MIL-125 was designed through the in situ Cu2+ ion reduction strategy. Under UV-vis light irradiation, the Cu2O/TiO2 composite with 4.2 wt% of Cu2O displayed the highest hydrogen evolution rate of 14.39 mmol h−1 g−1, which was about 9.6 and 24.8 times that of the original mesoporous TiO2 and pure Cu2O, respectively. The enhancement in photocatalytic activity can be mainly attributed to the type-I band structure formed, which can efficiently enhance the photoexcited charge carrier mobility across the phase interfaces of the Cu2O/TiO2 composite, as evidenced by the UV-DRS spectra, Mott–Schottky curves, and XPS analysis. Besides, the narrow band gap of Cu2O, conducive to the absorption of visible light, and the high specific surface of TiO2 were also found to contribute to the photoactivity enhancement. This work will provide a new perspective for the study of type-I photocatalysts. [ABSTRACT FROM AUTHOR]

Metastatic tumour recurrence caused by circulating tumour cells (CTCs) after surgery is responsible for more than 90% of tumour-related deaths. A postoperative evaluation system based on the long-term dynamic detection of CTCs helps in guiding the postoperative treatment of tumours in real time and preventing metastases and recurrence of tumours after treatment. In this study, a simple, rapid, and low-cost postoperative evaluation system was established based on the number of CTCs captured by a label-free acoustic separation device from whole blood samples of mice, of which breast tumours were surgically removed, and tumour metastasis was successfully predicted. First, an acoustofluidic device with a custom-designed bottom microcavity array was fabricated to induce highly localised acoustic microstreaming by applying acoustic vibration. Second, experiments of capturing 'defined' cells (artificially mixed individual 4T1 cancer cells into normal blood) based on optimal acoustic streaming were performed. The separation device exhibited a high capture efficiency (>96%). Further applications of capturing the 'true' CTCs derived from postoperative mice were successfully developed to predict tumour prognosis based on the number of captured CTCs. Finally, the prediction was verified through long-term observation of mice with excised tumours. The acoustofluidic device can efficiently capture CTCs and precisely predict tumour metastasis in a low-cost and non-invasive manner. This will help clinicians monitor patients that underwent surgical resection of tumours over a long period of time and facilitate optimal treatment strategies in a timely manner. [ABSTRACT FROM AUTHOR]

Capacity fading of Li4Ti5O12 (LTO) is inevitable during cycling; hence it is of great significance to clarify the factors causing the capacity degradation so as to take some measures to prolong the lifespan of LTO. Despite the investigation on the capacity fading mechanism within finite charge/discharge cycles, the fading mechanism during long-term cycling is still absent. Here, LTO half-cells underwent more than 700 lithiation/delithiation cycles at a current rate of 0.5 A g−1, and the changes in structure, composition, cyclic voltammogram and electrochemical impedance with cycling were probed systematically to comprehend the capacity decay. Except for the performance degradation that resulted from the electrolyte decomposition and gassing effect during cycling, the transition from spinel LTO to rock-salt Li7Ti5O12 accompanied by structural and compositional variation also leads to a capacity fading of LTO, namely, the repetitive lithiation/delithiation gives rise to more and more residual Li+ and Ti3+ in the delithiated LTO, structure disordering, gradually depressed ionic and electronic conductivities, and escalated polarization, thus aggravating the performance decay. [ABSTRACT FROM AUTHOR]

A 3D hierarchical Bi-doped CoP nanoflower electrocatalyst has been developed based on a MOF self-sacrifice strategy. 3% Bi/CoP delivers a current density of 10 mA cm−2 at low overpotentials of 122 mV in alkaline electrolyte and 150 mV in acidic electrolyte, respectively. DFT calculations demonstrate that Bi doping can synergistically optimize the binding free energy of H* on the CoP (202) facet and ultimately improve the HER performance. [ABSTRACT FROM AUTHOR]

The development of an iridium catalyzed enantioselective α-alkylation of azlactones has been described. The reaction provides rapid access to a wide range of enantio-enriched quaternary carbon center allylated 2,4-diaryloxazol-5(2H)-ones in excellent yields with high enantioselectivities. The transformation was achieved through a tandem allylic alkylation/aza-Cope rearrangement, affording the desired products under mild conditions. Ultimately, the resulting products could be readily converted into diverse enantio-enriched derivatives which highlight the importance of the methodology. [ABSTRACT FROM AUTHOR]

Three novel polyoxometalate (POM)-based metal–organic complexes (MOCs) constructed from rigid pyridyl-triazole-tetrazole and pyridyl-bis(triazole) ligands have been hydrothermally synthesized and structurally characterized: [Co3(Htyptz)2(γ-Mo8O26)(H2O)6]·4H2O (1), H2[Co3(Htyptz)2(TeMo6O24)(H2O)8]·6H2O (2), [Co3(Hpyttz)2(γ-Mo8O26)(H2O)8]·2H2O (3) (H2typtz = 3-(tetrazol-5-yl)-5-(pyrid-3-yl)-1,2,4-triazolyl, H2pyttz = 3-(pyrid-4-yl)-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl). Single-crystal X-ray diffraction analyses reveal that complex 1 is a 3D metal–organic framework. Both 2 and 3 are 2D metal–organic architectures. In complex 1, the adjacent [γ-Mo8O26]4− anions are linked by the CoII ions to form a 1D Co-γ-Mo8O26 inorganic chain. Then the 1D Co-γ-Mo8O26 inorganic chains are linked together by the 1D metal–organic Co-Htyptz chains to form a 3D framework. In complex 2, the adjacent Co-Htyptz metal–organic chains are connected by TeMo6 polyoxoanions to form a 2D architecture. In complex 3, [γ-Mo8O26]4− anions are bridged by the CoII ions to give similar 1D Co-γ-Mo8O26 inorganic chains to those in 1, which are connected through [Co(Hpyttz)2] units to form a 2D network. 1 and 2 represent the first examples of POM-based MOCs derived from H2typtz. The effects of the POM type and different ligands on the structures of the title complexes were discussed. The adsorption activities for organic dyes methylene blue (MB), gentian violet (GV), methyl orange (MO), rhodamine B (RhB), neutral red (NR) and safranin T (ST) have been investigated in detail. Furthermore, the electrochemical properties of 1 and 2 have been studied, which display electrocatalytic activities toward the reduction of nitrite and bromate. 1-CPE shows pH-dependent electrochemical behaviors and may be used as a potential sensor. [ABSTRACT FROM AUTHOR]

In this study, a naked-eye colorimetric sensor was fabricated based on a Schiff base (–SH) derivative immobilized onto polyvinyl alcohol (PVA) microspheres. The surface morphology of PVA-SH was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The PVA-SH microspheres could selectively detect Cu2+ by a visible color change. This novel chemosensor demonstrated high sensitivity and selectivity for the detection of Cu2+, which can induce a color change of PVA-SH from white to yellow. PVA-SH exhibited a detection limit of 0.086 μM for Cu2+. Moreover, this simple and cost-efficient chemosensor was used for detecting Cu2+ in actual environmental water samples. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) have attracted extensive attention over the past decade due to their excellent advantages. However, few attempts have been reported for realizing the long-wavelength emission, especially for obtaining efficient solid-state red emission with high photoluminescence quantum yield (QY). Herein, we developed highly red light emitting CDs by the step-by-step surface modifications of the nitrogen-doped CDs. By introducing hexadecyltrimethyl ammonium bromide to modulate a red CD aqueous solution, the photoluminescence QY increases from 23.2% to 43.6%. Furthermore, we dispersed CDs in a PVP matrix for a solid-state film, where the solid-state quenching was effectively suppressed, and high QY (41.3%) of red light emission was achieved. Taking advantage of the as-prepared red light emitting CDs combining with the reported high quantum yield blue and green light emitting CDs, we realized UV-pumped WLEDs with tunable correlated color temperature from 7879 to 2961 K. Moreover, a high color rendering index (CRI) of 93 for WLEDs was realized, which is superior than the best records for the semiconductor quantum dot based WLEDs. Finally, the red light emitting CDs were demonstrated to have promising application as a red color converter in traditional YAG-based WLEDs to improve their CCT and CRI. [ABSTRACT FROM AUTHOR]

Nowadays, obtaining a thin and large-area perovskite single-crystal (SC) is still challenging. Herein, we report a novel strategy to prepare a laminar MAPbBr3 SC with a controllable thickness of 16 μm and a size of 6 × 8 mm. Additionally, the SC solar cell achieves an intriguing efficiency of 7.11% with an impressive stability, maintaining 93% initial PCE after aging for 1000 h. [ABSTRACT FROM AUTHOR]

Manganese oxide was prepared by decomposing MnCO3 obtained from the reaction between Na2CO3 and MnCl2·4H2O, and a MnO/C composite was fabricated by processing the mixture of manganese oxide and pitch in a nitrogen atmosphere at 600 °C. Compared to the MnO/C composite obtained under the similar conditions using glucose as the carbon source, the composite containing the pitch-derived soft carbon demonstrates an improved initial Coulombic efficiency (from 57.2% to 68.8%), a stable capacity of 601.8 mA h g−1 at 100 mA g−1 after the 50th cycle, an outstanding capacity of 265 mA h g−1 even when cycling at 500 mA g−1 for 350 times, and superior rate capabilities. From the detailed characterization by X-ray diffraction, Raman spectroscopy, transmission electron microscopy and thermogravimetric analysis, it is found that the enhanced electrochemical performance associated with the improved electronic conductivity and high stability resulted from the higher graphitization degree of the pitch-derived soft carbon than the glucose-derived hard carbon. [ABSTRACT FROM AUTHOR]

Nitrogen-doped (N-doped) TiO2/SnO2 heterostructured microspheres with exposed mirror-like plane {001} facets were successfully fabricated by a conventional hydrothermal method and easy impregnation treatment. The morphology, structure and photocatalytic properties of the N-doped TiO2/SnO2 heterostructure were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, and transient photocurrent response. Characterization results indicated that in situ formed SnO2 nanoparticles were uniformly grafted onto N-TiO2 microspheres of ca. 2.0 μm in size. The mirror-like {001} surface of these microspheres was covered by square-shaped crystalline facets ca. 0.6 μm long. The formation of a heterojunction between SnO2 and N-TiO2 microspheres enhanced the separation efficiency of photogenerated electron–hole pairs and the light-harvesting capability, which significantly improved the photocatalytic performance. Furthermore, N-doped TiO2/SnO2 heterostructured microspheres with highly reactive {001} facets were used as a stable photocatalyst for the highest photocatalytic activity for bisphenol A degradation under UV and visible light irradiation compared with pristine TiO2 and N-TiO2. This result can be attributed to the unique structure and synergistic effect of the dominant mirror-like plane {001} facets, N doping and heterostructured interface. This study provides new possibilities for the development of TiO2 with a dominant {001} facet-based heterostructure for environmental purification. [ABSTRACT FROM AUTHOR]

In this study, an optical analytical naked-eye sensor based on thiourea–polyvinyl alcohol (PVA) microspheres was designed for the selective recognition of heavy metals in aqueous solutions. The colorimetric sensor was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy to confirm the linkage of the chromophore with the surface of PVA microspheres. In the sensing system, notable changes in absorbance intensity of the colorimetric sensor for Hg2+ and Cu2+ were observed at pH 3 and 4, respectively. The sensor could selectively recognize heavy metals, as shown by the change in color from faint yellow to orange for Hg2+ and from faint yellow to dark green for Cu2+. The sensor provided consistent data reliability, with a detection limit of 0.209 and 0.320 μM by UV-vis spectrometry for Hg2+ and Cu2+, respectively. The prepared colorimetric sensor can be used to monitor Hg2+ and Cu2+ with satisfactory results because of its selectivity, reversibility, sensitivity, and signal stability. [ABSTRACT FROM AUTHOR]

Controllable on-chip multimodal manipulation of micro-objects in microfluidic devices is urgently required for enhancing the efficiency of potential biomedical applications. However, fixed design and driving models make it difficult to achieve switchable multifunction efficiently in a single device. In this study, a versatile bubble-based acoustofluidic device is proposed for multimodal manipulation of micro-objects in a biocompatible manner. Identical bubbles trapped over the bottom microcavities are made to flexibly switch between four different oscillatory motions by varying the applied frequency to generate corresponding modes of streaming patterns in the microchannel. Such regular modes enable stable transportation, trapping, 3D rotation, and circular revolution of the micro-objects, which were experimentally and numerically verified. The mode-switchable manipulations can be noninvasively applied to particles, cells, and organisms with different sizes, shapes, and quantities and can be controlled by key driving parameters. Moreover, 3D cell reconstruction is developed by applying the out-of-plane rotational mode and analyzed for illustration of cell surface morphology while quantifying reliably basic cell properties. Finally, a simple platform is established to integrate user-friendly function control and reconstruction analysis. The mode-switchable acoustofluidic device features a versatile, controllable, and contactless micro-object manipulation method, which provides an efficient solution for biomedical applications. [ABSTRACT FROM AUTHOR]

To solve the energy crisis and environmental pollution problems, the use of clean and renewable energy to replace fossil energy has become a top priority. The oxygen evolution reaction (OER) is the core of many renewable energy technologies. Developing low-cost and high-performance OER electrocatalysts is the key to implementing efficient energy conversion processes. Here, we synthesize ordered mesoporous iron–cobalt oxides using a hard template strategy. As a mesoporous oxide catalyst, meso-CoFe0.05Ox exhibits low OER overpotentials of 280 and 373 mV at current densities of 10 and 100 mA cm−2, respectively, and does not show deactivation for at least 18 hours at 100 mA cm−2. The introduction of iron can change the electronic structure of Co, and the orbital electrons are easily transferred from cobalt to iron. The enhanced OER performance can be attributed to concerted catalysis between the iron and cobalt sites that lowers the OER energy barrier, and the large specific surface area of the porous oxide providing efficient active sites for the reaction. [ABSTRACT FROM AUTHOR]

Correction for 'Enantioselective iridium catalyzed α-alkylation of azlactones by a tandem asymmetric allylic alkylation/aza-Cope rearrangement' by Xue-Dan Bai et al., Chem. Commun., 2019, 55, 5547–5550. [ABSTRACT FROM AUTHOR]

The development of high activity and strong resistance to seawater corrosion oxygen evolution reaction (OER) electrocatalysts for seawater electrolysis has broad application prospects. Herein, we prepare Co-doped FeNiOOH rosette-like nanoflowers on nickel foam (NF) with different Co dosages by one-step solvothermal method. The Co0.2-FeNiOOH/NF exhibits a low overpotential (η10) of 185 mV and Tafel slope of 30 mV dec−1 in 1 M KOH. Moreover, it shows a low η10 of 244 mV in alkaline seawater electrolyte. The remarkable OER performance of Co0.2-FeNiOOH/NF is ascribed to the fact that the introduction of Co regulates the morphology and electron structure of the material, which provides abundant active sites for the reaction and promotes charge transfer. In situ Raman results demonstrate that NiOOH and γ-FeOOH are the key active species for the OER. This study provides a feasible basis for seawater electrolysis over transition metal (oxy)hydroxides. [ABSTRACT FROM AUTHOR]

High-entropy materials (HEMs) have potential application value in electrocatalytic water splitting because of their unique alloy design concept and significant mixed entropy effect. Here, we synthesize a high-entropy Ni–Fe–Cr–Mn–Co (oxy)hydroxide on nickel foam (NF) by a solvothermal method. The flower-like structure of FeNiCrMnCoOOH/NF can provide abundant active sites, thus improving the oxygen evolution reaction (OER) activity. In 1 M KOH, the FeNiCrMnCoOOH/NF shows an ultra-low overpotential (η10) of 201 mV for the OER, superior to FeNiCrMnAlOOH/NF, FeNiCrMnCuOOH/NF, FeNiCrMnMoOOH/NF, and FeNiCrMnCeOOH/NF. In addition, it exhibits a low η10 of 223 mV in 0.5 M NaCl + 1 M KOH and excellent stability. Electrochemical impedance spectroscopy measurements indicate that the synergistic effect between multiple metals accelerates charge transfer, while in situ Raman measurements reveal that NiOOH is a key active species for the OER. This work is of great significance for the construction of high-entropy (oxy)hydroxides for seawater electrolysis. [ABSTRACT FROM AUTHOR]

An effective method to eliminate grain boundary resistance of crystalline vanadoborate electrolyte was developed. This method involved the addition of glycerol to result in the formation of many hydrogen bonds between crystal grains, facilitating a rapid transfer of protons across grain boundaries. Using this method, the intrinsic conduction of vanadoborate electrolyte was fully reflected in its bulk materials, valuable for advancing our understanding of vanadoborate electrolytes and for promoting the application of these electrolytes. [ABSTRACT FROM AUTHOR]

Developing multifunctional metal–organic frameworks (MOFs) is a new research trend. MOFs have shown remarkable performances in both proton conduction and fluorescence sensing, but the MOFs integrating the two performances are scarce. Herein, a Co-MOF, [Co6(oba)4(Hatz)(atz)(H2O)2(μ3-OH)2(μ2-OH)]·H2O (1, H2oba = 4,4-oxybis(benzoic acid), Hatz = 5-amino-1H tetrazole), has been assembled by Co2+ ions with H2oba and Hatz ligands, providing a unique example of multifunctional MOFs with both proton conduction and fluorescence sensing performances. The framework of 1 displays a pillar-layer structure built by the oba ligand as a pillar and a layer composed of Co-clusters and atz linkers. Because large-scale single crystals of 1 were successfully synthesized, the proton conduction ability of 1 was investigated using single crystal samples. 1 exhibits highly anisotropic conduction with conductivity values of 1.1 × 10−3 S cm−1 along the [001] direction and 9.1 × 10−6 S cm−1 along the [010] direction at 55 °C and 95% RH, respectively. Meanwhile, the fluorescence sensing of 1 towards metal ions was studied in aqueous solutions. Attractively, 1 may sensitively and selectively detect Fe3+ ions in the presence of other interfering ions by fluorescence quenching. [ABSTRACT FROM AUTHOR]

The rational design of non-noble materials as low-cost, highly efficient, and durable catalysts to improve the oxygen reduction reaction is extremely urgent and challenging. The oxygen reduction reaction is a kinetically sluggish process that greatly affects the energy conversion efficiency. In this paper, novel hierarchical heteroatoms-co-doped Fe2M/graphene (M = P, N) nanocomposites were developed by a facile strategy, including hydrothermal and subsequent calcination methods. The thermal treatment of an ionic liquid and thiourea not only supplied heteroatom sources but also promoted the formation of iron phosphide and iron nitride and enhanced their catalytic performances. The electrochemical results indicated that the as-obtained hybrid catalysts manifested enhanced electrocatalytic activity toward the oxygen reduction reaction owing to the strong synergistic effects. The high content of heteroatoms distributed on the surface and interface of the hybrids and the density functional theory calculations suggested that Fe–N–C, Fe–P–C, and Fe–S–C multiple active surface sites were formed at the hybrids interfaces. Moreover, these results demonstrated that heteroatom-doped catalysts could effectively form a charge-transfer channel and thus modify the charge distribution in the hybrids interfaces. The as-prepared heteroatoms-doped Fe2M/graphene hybrids would be developed into highly efficient catalysts as ideal alternatives for noble metal catalysts in practical applications. [ABSTRACT FROM AUTHOR]

The structure of CsPbI3 nanocrystals (NCs) with excellent photoelectric properties easily collapses, which hinders their application in light-emitting diodes (LEDs). Herein, we accomplished the synthesis of efficient and stable CsPbI3 NCs by regulating structural rigidity under the synergistic effect of Mg2+ and AcO− ions. The introduced AcO− and Mg2+ ions increase surface steric hindrance and defect formation energy, which enhances the structural rigidity of the perovskite. As a result, the CsPbI3 NCs display an outstanding photoluminescence quantum yield of 95.7%, in conjunction with reduced defect state density, balanced carrier injection, and distinguished conductivity. Remarkably, the modified CsPbI3 NCs exhibit excellent stability under ambient conditions for 180 days and can even survive when the temperature reaches 150 °C. Given their enhanced structural rigidity, LEDs made from these modified CsPbI3 NCs exhibit a maximum luminance and an EQE of 3281 cd m−2 and 13.2%, respectively, which are significantly improved compared with those of unmodified CsPbI3 NC LEDs. [ABSTRACT FROM AUTHOR]

The exploration of LDHs for the selective adsorption of NO3− from water has been proposed for a long time; however, their complex fabrication methods and unclear adsorption mechanism limit their further utilization. Considering this, herein, a systematic investigation was conducted by synthesizing Mg3Al-LDHs with different morphologies via the co-precipitation method with different alkali sources including individual NaOH and Na2CO3, and mixed alkali sources of NaOH and Na2CO3 to remove NO3− from water. Their detailed microstructure and morphologies were characterized and the influence of the alkali source on the NO3− removal rate for the Mg3Al-LDHs was fully investigated. Based on the results, LDHs prepared with NaOH as the alkali source could weaken the agglomeration of the Mg3Al–LDH layers, thus exposing the active adsorption sites on their surface and reducing their mesoporous pore size to 3.38 nm, which enhanced their adsorption capacity for NO3−. Consequently, the adsorption performance of LDHs for NO3− was investigated considering the influencing factors including time, temperature, and initial concentration. It was found that the sorption process could be well described by pseudo-second-order kinetics and the Langmuir isotherm model. The maximum monolayer adsorption capacity on NO3− was calculated to be 6.1 mg g−1 at 298 K. Meanwhile, the thermodynamic results indicated that the adsorption removal of NO3− is spontaneous (ΔG0 < 0) and exothermic (ΔH0 < 0). Additionally, the enhanced adsorption performance is attributed to the combination of physisorption driven by intermolecular forces and chemisorption caused by ion exchange. Therefore, due to the scalable fabrication of Mg3Al-LDHs with the addition of NaOH as an alkali source, they can be a potential adsorbent for the removal of NO3−–N from water. [ABSTRACT FROM AUTHOR]

Optoelectronic tweezers (OET) is a noncontact micromanipulation technology for controlling microparticles and cells. In the OET, it is necessary to configure a medium with different electrical properties to manipulate different particles and to avoid the interaction between two particles. Here, a new method exploiting the interaction between different dielectric properties of micro-objects to achieve the trapping, transport, and release of particles in the OET system was proposed. Besides, the effect of interaction between the micro-objects with positive and negative dielectric properties was simulated by the arbitrary Lagrangian–Eulerian (ALE) method. In addition, compared with conventional OET systems relying on fabrication processes involving the assembly of photoelectric materials, a contactless OET platform with an iPad-based wireless-control interface was established to achieve convenient control. Finally, this platform was used in the interaction of swimming microorganisms (positive-dielectric properties) with microparticles (negative-dielectric properties) at different scales. It showed that one particle could interact with 5 particles simultaneously, indicating that the interaction can be applied to enhance the high-throughput transportation capacities of the OET system and assemble some special microstructures. Owing to the low power, microorganisms were free from adverse influence during the experiment. In the future, the interaction of particles in a simple OET platform is a promising alternative in micro–nano manipulation for controlling drug release from uncontaminated cells in targeted therapy research. [ABSTRACT FROM AUTHOR]

Thermal stability and thermal management are critical to the performance of organic transistors/solar cells. However, these properties are rarely studied due to the limited techniques for measuring the thermal conduction of organic thin-film crystals. Using an active mode scanning thermal microscope (SThM), we quantitatively measured the thermal map of layered 1,4-bis(4-methylstyryl)benzene (BSB-Me) thin-film crystals. The out-of-plane thermal conductivity was calculated to be ∼0.15–0.20 W m−1 K−1 by comparing the temperature distributions of the thermal probe with the results of COMSOL Multiphysics simulations. This thickness-dependent SThM measurement provides important thermal-transport information of organic thin-film devices, where thermal dissipation is crucial. [ABSTRACT FROM AUTHOR]

Bi2O2CO3 clusters made up of ultrathin nanosheets with predominated {001} facets were facilely synthesized via a template-free hydrothermal strategy at a mild temperature of 60 °C. Na2CO3 dosage and reaction temperature are confirmed to be key parameters to obtain the hydrolysis product of (Bi2O2)2+ from bismuth nitrate and provide a suitable microenvironment for the assembly of nanosheets. The sample exhibits obviously improved photocatalytic activity for the degradation and mineralization of Rhodamine B compared with thicker Bi2O2CO3 plates of less exposed {001} planes, with the reaction rate constant k enhanced by 3.4 fold. Photoluminescence and electrochemical impedance results confirm that the {001} facets are reactive and favorable for the separation and migration of photogenerated carriers, which primarily account for the superior photocatalytic behavior of the Bi2O2CO3 clusters. In addition, the enhanced specific surface area should also contribute to the improved photocatalytic activity. Based on the band edge positions of Bi2O2CO3 and the redox potentials of detected oxidative species, a possible migration mechanism of photogenerated e−/h+ pairs on the surface of Bi2O2CO3 is proposed. This work provides some new insight into the rational design and synthesis of facet-dependent semiconductor photocatalyst under mild conditions. [ABSTRACT FROM AUTHOR]