Solution‐Processed Two‐Dimensional MoS2 Nanosheets: Preparation,Hybridization, and Applications

As one member of the emerging class of ultrathin two‐dimensional (2D) transition‐metal dichalcogenide (TMD) nanomaterials, the ultra‐thin MoS₂ nanosheet has attracted increasing research interest as a result of its unique structure and fascinating properties. Solution‐phase methods are promising for the scalable production, functionalization, hybridization of MoS₂ nanosheets, thus enabling the widespread exploration of MoS₂‐based nanomaterials for various promising applications. In this Review, an overview of the recent progress of solution‐processed MoS₂ nanosheets is presented, with the emphasis on their synthetic strategies, functionalization, hybridization, properties, and applications. Finally, the challenges and opportunities in this research area will be proposed.     

Au‐TiO2/Graphene Nanocomposite Film for Electrochemical Sensing of Hydrogen Peroxide and NADH

We describe a simple method for preparing Au‐TiO₂/graphene (GR) nanocomposite by deposition of Au nanoparticles (NPs) on TiO₂/GR substrates. The as‐prepared Au‐TiO₂/GR was characterized by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The presence of Au NPs on TiO₂/GR surface remarkably improves the electrocatalytic activity towards the oxidation of hydrogen peroxide (H₂O₂) and β‐nicotinamide adenine dinucleotide (NADH). The Au‐TiO₂/GR modified glassy carbon (GC) electrode exhibits good amperometric response to H₂O₂ and NADH, with linear range from 10 to 200 µM and 10 to 240 µM, and detection limit of 0.7 and 0.2 µM, respectively.     

Synthesis and characterization of some methylbismuth (III) O,O‐alkylenedithiophosphates: convenient transformation of and to pure Bi2S3

A series of methylbismuth(III)O,O‐alkylenedithiophosphates of the type [where G = CH₂CH(CH₃) ( 1 ), (CH₂)₄ ( 2 ), CH₂CH₂CH(CH₃) ( 3 ), CH(CH₃)CH(CH₃) ( 4 ), CH₂CHCH₂CH₃ ( 5 ), CH(CH₃)CH₂C(CH₃)₂ ( 6 ) and C(CH₃)₂C(CH₃)₂ ( 7 )] have been isolated by the reaction of methylbismuth(III) dichloride with potassium salt of O,O‐alkylenedithiophosphoric acids in 1:2 molar ratio in anhydrous benzene. These newly synthesized derivatives were characterized by elemental analyses, FT IR and multinuclear NMR (¹H, ¹³C and ³¹P) spectral studies. Thermogravimetric analysis of 6 has shown a single‐step decomposition of complex to Bi₂S₃ at 154.3 °C. Transformation of 2 and 6 to pure Bi₂S₃ was carried out successfully at refluxing xylene temperature (142 °C) as revealed by XRD and SEM analyses. Copyright © 2006 John Wiley & Sons, Ltd.     

Vacuum Ultraviolet Excited Photoluminescence Properties of Y202S:Eu3+,Bi3+ Phosphor

As an Hg-free lamp using phosphor,the Bi3+ and Eu3+ co-doped Y2O2S phosphors were prepared and their luminescence properties under vacuum uitraviolet(VUV) excitation were investigated.The VUV photolumineseent intensity of Y2O2S:Eu3+ was weak,however,considerably stronger red emission at 626 nm with good color purity was observed in Y2O2S:Eu3+,Bi3+ systems.Investigation on the photoluminescence reveals that the strong VUV luminescence of Y2O2S:Eu3+,Bi3+ at 147 nm is mainly because the Bi3+ acts as a medium and effectively performs the energy transfer process: Y3+-O2→Bi3+→Eu3+,while the intense emission band at 172 nm is attributed to the absorption of the characteristic 1So-1P1 transition of Bi3+ and the direct energy transfer from Bi3+ to Eu3+.The Y2O2S:Eu3+,Bi3+ shows excellent VUV optical properties compared with the commercial (Y,Gd)BO3:Eu3+.Thus,the Y2O2S:Eu3+,Bi3+ can be a potential red VUV-excited candidate applied in Hg-free lamps for backlight of liquid crystal display.     

The Hybrid of Gold Nanoparticles and 3D Flower‐like MnO2 Nanostructure with Enhanced Activity for Detection of Hydrogen Peroxide

3D Flower‐like manganese dioxide (MnO₂) nanostructure with the ability of catalysis for hydrogen peroxide (H₂O₂) and super large area that can support gold nanoparticles (AuNPs) with enhanced activity of electron transfer have been developed. The nanostructure of hybrids was prepared by directly mixing citric‐capped AuNPs and 3‐aminopropyltriethoxysilane (3‐APTES)‐capped nano‐MnO₂ using an electrostatic adsorption strategy. The Au‐MnO₂ composite was extensively characterized by scanning electron microscope (SEM), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), the Brunauer‐Emmett‐Teller (BET) method and X‐ray photoemission spectroscopy (XPS). Electrochemical properties were evaluated through cyclic voltammetry (CV) and amperometric method. The prepared sensor showed excellent electrochemical properties towards H₂O₂ with a wide linear range from 2.5×10⁻³∼1.39 mM and 3.89∼13.89 mM. The detection limit is 0.34 μM (S/N=3) with the sensitivities of 169.43 μA mM⁻¹ cm⁻² and 55.72 μA mM⁻¹ cm⁻². The detection of real samples was also studied. The result exhibited that the prepared sensor can be used for H₂O₂ detection in real samples.     

Sb2S3纳米粒子修饰ZnO纳米片微纳分级结构的光电化学性能

采用恒电位方法,选择氯化钾和乙二胺(EDA)为添加剂,在氧化铟锡(ITO)导电玻璃上制备了高度有序的ZnO纳米片阵列,通过二次电沉积得到了ZnO纳米片上生长纳米棒的微纳分级结构.利用化学浴沉积法在ZnO基底上沉积Sb₂S₃纳米粒子制备出了Sb₂S₃/ZnO纳米片壳核结构和Sb₂S₃/ZnO微纳分级壳核结构.利用扫描电子显微镜(SEM)、X射线衍射(XRD)、紫外-可见(UV-Vis)吸收光谱、瞬态光电流等对其形貌、结构组成和光电化学性能进行了表征和分析.结果表明, Sb₂S₃/ZnO纳米片上生长纳米棒分级壳核结构的光电流明显高于Sb₂S₃/ZnO纳米片壳核结构.在Sb₂S₃/ZnO纳米片壳核结构和Sb₂S₃/ZnO微纳分级壳核结构的基础上旋涂一层P3HT薄膜形成P3HT/Sb₂S₃/ZnO复合结构,以上述复合结构薄膜为光活性层组装成杂化太阳电池,其中, P3HT/Sb₂S₃/ZnO分级壳核结构杂化太阳电池的能量转换效率最高,达到了0.81%.     

Facile Synthesis and Thermoelectric Properties of Self‐assembled Bi2Te3 One‐Dimensional Nanorod Bundles

Self‐assembled Bi₂Te₃ one‐dimensional nanorod bundles have been fabricated by a low‐cost and facile solvothermal method with ethylene diamine tetraacetic acid as an additive. The phase structures and morphologies of the samples were characterized by X‐ray diffraction, scanning electron microscopy, Fourier‐transform infrared spectrometry, and transmission electron microscope measurements. The growth mechanisms have been proposed based on the experimental results. The full thermoelectric properties of the nanorod bundles have been characterized and show a large improvement in the thermal conductivity attributed to phonon scattering of the nanostructures and then enhance the thermoelectric figure of merit. This work is promising for the realization of new types of highly efficient thermoelectric semiconductors by this method.     

Improving the Field‐Effect Performance of Bi2S3 Single Nanowires by an Asymmetric Device Fabrication

High‐quality Bi₂S₃ nanowires are synthesized by chemical vapor deposition and their intrinsic photoresponsive and field‐effect characteristics are explored in detail. Among the studied Au–Au, Ag–Ag, and Au–Ag electrode pairs, the device with stepwise band alignment of asymmetric Au–Ag electrodes has the highest mobility. Furthermore, it is shown that light can cause a sevenfold decrease of the on/off ratio. This can be explained by the photoexcited charge carriers that are more beneficial to the increase of I_off than I_on. The photoresponsive properties of the asymmetric Au–Ag electrode devices were also explored, and the results show a photoconductive gain of seven with a rise time of 2.9 s and a decay time of 1.6 s.     

Decomposition and Detection of Hydrogen Peroxide Using δ‐MnO2 Thin Film Electrode with Self‐Healing Property

A thin film of δ‐type MnO₂ grown cathodically has been investigated with respect to the ability toward anodic decomposition of H₂O₂ and durability. With polarization at less positive potentials than +0.4 V vs. Ag/AgCl, the film was dissolved exclusively as a result of reduction of Mn⁴⁺ sites in the oxide by H₂O₂ to soluble Mn²⁺. At +0.9 V, MnO₂ remained unchanged and decomposed H₂O₂ in solution. At +0.8 V, the film was once dissolved in the initial stage; however, it was self‐healed via reoxidation of the liberated Mn²⁺ ions. Amperometric flow‐injection analysis of H₂O₂ was carried out with the δ‐MnO₂ film.     

Morphology Control of Bi2S3 Nanostructures and the Formation Mechanism

Bismuthinite (Bi₂S₃) nanostructures were prepared by a hydrothermal method with sodium ethylenediaminetetraacetate (EDTA‐Na₂). The morphology of Bi₂S₃ nanostructures was changed from a nanorod to a nanoplate by presence of the EDTA‐Na₂. The altered morphology was caused by the capping effect of EDTA‐Na₂ with Bi³⁺ ions, which induces the suboptimal growth direction due to partially blocking the preferential orientation direction. When the EDTA‐Na₂/Bi³⁺ molar ratio=1, the growth of Bi₂S₃ nanostructures was not allowed due to the chelating effect of EDTA‐Na₂. The obtained Bi₂S₃ nanorods, stacked nanorods, nanoplates and nanoparticles were characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), high‐resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) pattern. A possible formation mechanism of these morphologies was proposed. The successful synthesis of various morphologies of nanostructured Bi₂S₃ may open up new possibilities for thermoelectric, electronic and optoelectronic uses of nanodevices based on Bi₂S₃ nanostructure.     

Synthesis and Localized Photoluminescence Blinking of Lead‐Free 2D Nanostructures of Cs3Bi2I6Cl3 Perovskite

Two‐dimensional (2D) lead‐free halide perovskites have generated enormous perception in the field of optoelectronics due to their fascinating optical properties. However, an in‐depth understanding on their shape‐controlled charge‐carrier recombination dynamics is still lacking, which could be resolved by exploring the photoluminescence (PL) blinking behaviour at the single‐particle level. Herein, we demonstrate, for the first time, the synthesis of nanocrystals (NCs) and 2D nanosheets (NSs) of layered mixed halide, Cs₃Bi₂I₆Cl₃, by solution‐based method. We applied fluorescence microscopy and super‐resolution optical imaging at single‐particle level to investigate their morphology‐dependent PL properties. Narrow emission line widths and passivation of non‐radiative defects were evidenced for 2D layered nanostructures, whereas the activation of shallow trap states was recognized at 77 K. Interestingly, individual NCs were found to display temporal intermittency (blinking) in PL emission. On the other hand, NS showed temporal PL intensity fluctuations within localized domains of the crystal. In addition, super‐resolution optical image of the NS from localization‐based method showed spatial inhomogeneity of the PL intensity within perovskite crystal.     

Synthesis of PtxSn/MWCNTs and their Application in Non‐enzymatic Glucose and Hydrogen Peroxide Sensors

Pt_xSn/MWCNTs (x=1, 2, 3) nanocomposites were synthesized by chemical reduction. Comparing all of the materials, the results revealed that the best material was Pt₃Sn/MWCNTs. The sensor based on Pt₃Sn/MWCNTs exhibited excellent catalytic activities towards glucose and hydrogen peroxide. Sensing of glucose had a double‐linear range: one was between 50 μM and 550 μM, the other was between 1.35 mM and 16.35 mM. These were due to the fact that more and more intermediate species were adsorbed onto the electrode surface with increasing concentration of glucose, which limited the following glucose oxidation. Meanwhile, the sensor also had a linear response range between 0.05 mM and 18.95 mM for hydrogen peroxide. Furthermore, the glucose and hydrogen peroxide sensors exhibited excellent selectivity, stability, and reproducibility. Thus the sensors had potential utilities in the detection of glucose and hydrogen peroxide.     

Bipolar Electrochemistry Exfoliation of Layered Metal Chalcogenides Sb2S3 and Bi2S3 and their Hydrogen Evolution Applications

Efficient exfoliation and downsizing of Sb₂S₃ and Bi₂S₃ layered compounds by using scalable bipolar electrochemistry on their suspensions in aqueous media are here demonstrated. The resulting samples were characterized in detail by transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy; their electrochemistry toward hydrogen evolution was also investigated. Hydrogen evolution ability of exfoliated Sb₂S₃ and Bi₂S₃ was investigated and compared to the bulk counterparts.     

Synthesis of Two‐dimensional Microporous Carbonaceous Polymer Nanosheets and Their Application as High‐performance CO2 Capture Sorbent

The synthesis of two‐dimensional (2D) polymer nanosheets with a well‐defined microporous structure remains challenging in materials science. Here, a new kind of 2D microporous carbonaceous polymer nanosheets was synthesized through polymerization of a very low concentration of 1,4‐dicyanobenzene in molten zinc chloride at 400–500 °C. This type of nanosheets has a thickness in the range of 3–20 nm, well‐defined microporosity, a high surface area (～537 m² g^?1), and a large micropore volume (～0.45 cm³ g^?1). The microporous carbonaceous polymer nanosheets exhibit superior CO₂ sorption capability (8.14 wt % at 298 K and 1 bar) and a relatively high CO₂ selectivity toward N₂ (25.6). Starting from different aromatic nitrile monomers, a variety of 2D carbonaceous polymer nanosheets can be obtained showing a certain universality of the ionothermal method reported herein.     

Facile Halogenation of Pyrazolate‐Bridged Copper(I) Complexes: Synthesis,Crystal Structure,and Photoluminescent Properties

Solvothermal reactions of 3,5‐dimethylpyrazole (Me₂pz), and CuX in MeOH afforded two trinuclear complexes [Cu(XMe₂pz)]₃ [X = I ( 1 ); Br ( 2 )], where the halogenated ligand XMe₂pz in 1 and 2 were in‐situ formed from the reaction of Me₂pz with X^–. The crystal structure of 1 was determined by X‐ray crystallography. It turned out that it has a classic [Cu₃N₆] unit. The luminescence properties of 1 and 2 were investigated and the results show that both complexes have high photoluminescence quantum yields of 62 % and 84 % and long lifetimes of 21.7 μs and 30.5 μs, respectively.     

Sensitive Electrochemical Detection of Pb(II) and H2O2 via a Dual-functional Sn-doped Defective Bi2S3 Microspheres

In this work, a dual-functional electrochemical sensor has been proposed based on Sn-doped defective Bi₂S₃ (TDDB) microspheres, which exhibited the excellent electrochemical performance on Pb(II) and H₂O₂ detection. The TDDB offered a satisfied detection limit of 8.0 nM towards Pb(II) with a sensitivity of 96.7 μA ⋅ μM⁻¹. As a H₂O₂ sensor, a high sensitivity of 3540 μA mM⁻¹ cm⁻² was obtained in a linear range from 0.45 mM to 10 mM with a detection limit of 10 nM. Moreover, the electrochemical detection of Pb(II) in Taihu Lake and H₂O₂ in human serum was achieved with high reliability and good recovery.     

Catalytic Synthesis of Organolithium and Organomagnesium Compounds and of Lithium and Magnesium Hydrides—Applications in Organic Synthesis and Hydrogen Storage

A recent development in homogeneous catalysis is the discovery of catalysts that are active for the lithiation of 1-alkenes to alkenyllithium compounds and lithium hydride as well as for the hydrogenation of lithium and magnesium under mild conditions. The catalytically prepared magnesium hydride is highly reactive and adds to 1-alkenes to give diorganomagnesium compounds and can also be used in the preparation of, for example, silane and “active” magnesium. The use of metal hydrides in hydrogen storage is discussed: hydrogenation/dehydrogenation experiments show that the catalytically prepared magnesium hydride (which can be doped with a second metal) can be used as a high-temperature hydrogen storage material.     

Ni3S2@碳纳米管复合材料的制备及其储钠性能

采用一步固相煅烧工艺制备了碳纳米管原位封装Ni₃S₂纳米颗粒（Ni₃S₂@CNT）,并研究了其作为钠离子电池（SIBs）负极材料的电化学性能. 通过X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、循环伏安测试、恒流充放电以及交流阻抗等研究了Ni₃S₂@CNT的物相结构、形貌特征以及电化学性能. 电化学测试表明,材料在100 mA·g ^-1电流密度下,放电容量可以达到541.6 mAh·g ^-1,甚至在2000 mA·g ^-1的大电流密度下其放电比容量也可以维持在274.5 mAh·g ^-1. 另外,材料在100 mA·g ^-1电流密度下,经过120周充放电循环后其放电和充电比容量仍然可以保持在374.5 mAh·g ^-1和359.3 mAh·g ^-1,说明其具有良好倍率性能和循环稳定性能. 良好的电化学性能归因于这种独特的碳纳米管原位封装Ni₃S₂纳米颗粒结构. 碳纳米管不但可以提高复合材料的导电性,也可以缓冲Ni₃S₂纳米颗粒在反复充放电过程中产生的体积膨胀效应,明显改善了Ni₃S₂@CNT负极复合材料的电化学性能.