Nanocrystalline tin compounds/graphene nanocomposite electrodes as anode for lithium-ion battery

Nanocrystalline tin (Sn) compounds such as SnO₂, SnS₂, SnS, and graphene nanocomposites were prepared using hydrothermal method. The X-ray diffraction (XRD) pattern of the prepared nanocomposite reveals the presence of tetragonal SnO₂, hexagonal SnS₂, and orthorhombic SnS crystalline structure in the SnO₂/graphene nanosheets (GNS), SnS₂/GNS, and SnS/GNS nanocomposites, respectively. Raman spectroscopic studies of the nanocomposites confirm the existence of graphene in the nanocomposites. The transmission electron microscopy (TEM) images of the nanocomposites revealed the formation of homogeneous nanocrystalline SnO₂, SnS_2, and SnS particle. The weight ratio of graphene and Sn compound in the nanocomposite was estimated using thermogravimetric (TG) analysis. The cyclic voltammetry experiment shows the irreversible formation of Li₂O and Li₂S, and reversible lithium-ion (Li-ion) storage in Sn and GNS. The charge–discharge profile of the nanocomposite electrodes indicates the high capacity for the Li-ion storage, and the cycling study indicates the fast capacity fading due to the poor electrical conductivity of the nanocomposite electrodes. Hence, the ratio of Sn compounds (SnO₂) and GNS have been altered. Among the examined SnO₂:GNS nanocomposites ratios (35:65, 50:50, and 80:20), the nanocomposite 50:50wt% shows high Li-ion storage capacity (400 mAh/g after 25 cycles) and good cyclability. Thus, it is necessary to modify GNS and Sn compound composition in the nanocomposite to achieve good cyclability.     

Formation of SnS,SnS<Subscript>2</Subscript>, and PbS films from thiourea coordination compounds

Deposition of semiconductor tin and lead sulfide films from thiourea coordination compounds was examined. The nature of the ligands in the intermediate complexes formed was determined, and the influence of these precursors on the formation and phase composition of SnS, SnS₂, and PbS thin layers was examined.     

Physical vapor deposition of SnS:PbS-dithiocarbamate chalcogenide semiconductor thin films: elucidation of optoelectronic and electrochemical features

Abstract

This work reports the first investigation on the physical vapor deposition of thin films of tin sulfide doped lead sulfide (SnS:PbS). In-situ synthesis route using diethyldithiocarbamate (DTC) ligand was adopted for SnS-DTC, PbS-DTC and SnS:PbS-DTC complex formation. PbS-DTC and SnS:PbS-DTC expressed an average crystallite size of 30.98 and 29.74?nm, respectively shown by X-ray diffraction (XRD) analysis. A face centered cubic geometry was revealed from XRD. Ultraviolet visible spectrophotometry expressed a direct and indirect band gap of 3.4 and 3.2?eV, respectively for SnS:PbS-DTC. A smooth morphology with presence of larger agglomerated particles was disclosed by scanning electron microscopy for SnS:PbS-DTC thin films with 615?nm thickness. SnS:PbS-DTC thin films expressed remarkable electrochemical behavior explored via cyclic voltammetry, linear sweep voltammetry and chronoamperometry showing an improvement in the photo-current response upon potential bias increment. The results of the current research indicated the potential of SnS:PbS-DTC thin films for utilization in different types of photovoltaic devices.     

The Synthesis of SnS2 Nanoflakes from Tetrabutyltin Precursor

Hexagonal phase SnS₂ nanoflakes have been synthesized by reactions between an organotin precursor tetrabutyltin [TBT, (CH₂CH₂CH₂CH₃)₄Sn] and carbon disulfide in hexanes at 180-200°C for 10-40 h. The structure, morphologies, composition, and properties have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), ICP-AES, and Raman and Mössbauer spectroscopies. XRD patterns determined the hexagonal SnS₂ with lattice parameters a=3.6384 Å, c=5.9201 Å obtained in n-hexane, and a=3.6389 Å, c=5.9288 Å in cyclohexane. The flakelike morphologies were mainly caused by the anisotropic growth of SnS₂. A possible mechanism is given in the paper.     

SnS2纳米材料的水热合成及光催化性质

在不同的表面活性剂和硫源的条件下,采用水热法制备了多种形貌的SnS₂纳米材料,详细讨论了反应条件对其形貌和性质的影响,并采用X射线衍射(XRD)、扫描电镜(SEM)、和BET比表面积法对制备的样品的物相、形貌和组成进行了表征,通过光催化降解罗丹明B研究了所得样品的光催化性能。结果表明：表面活性剂和硫源对产物的结构和形貌起到了重要的作用。当Sn⁴⁺与表面活性剂的物质量的比为1：1时,样品均为纯的六方相SnS₂。采用柠檬酸三钠为表面活性剂、硫脲为硫源时制得的SnS₂纳米片具有最大的比表面积,同时表现出了最优的光催化性能。     

Synthesis and electrochemical properties of graphene-SnS2 nanocomposites for lithium-ion batteries

Graphene-SnS₂ nanocomposites were prepared via a solvothermal method with different loading of SnS₂. The nanostructure and morphology of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD patterns revealed that hexagonal SnS₂ was obtained. SEM and TEM results indicated that SnS₂ particles distributed homogeneously on graphene sheets. The electrochemical properties of the samples as active anode materials for lithium-ion batteries were examined by constant current charge–discharge cycling. The composite with weight ratio between graphene and SnS₂ of 1:4 had the highest rate capability among all the samples and its reversible capacity after 50 cycles was 351 mAh/g, which was much higher than that of the pure SnS₂ (23 mAh/g). With graphene as conductive matrix, homogeneous distribution of SnS₂ nanoparticles can be ensured and volume changes of the nanoparticles during the charge and discharge processes can be accomodated effectively, which results in good electrochemical performance of the composites.     

Preparation and electrochemical performances of carbon-coated nanoscale SnS for supercapacitors

Carbon-coated SnS as electrode materials for supercapacitor were synthesized by high-energy ball milling and following co-heating with polyvinyl alcohol. The morphology and structure of prepared carbon-coated SnS were studied by high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). Electrochemical investigation indicated that carbon-coated SnS presented preferable electrochemical performances than pristine SnS. In comparison to pristine SnS, carbon-coated SnS had better capacitive response in cyclic voltammetry and could deliver larger specific capacitance of 28.47 F/g in galvanostatical charge–discharge process. Enhanced conductivity of carbon-coated SnS revealed by Nyquist plots was considered to be responsible for its enhanced electrochemical performances.     

Effect of synthesis parameters on the structural,morphological characteristics,and photocatalytic activity of La2O3 nanoparticles

This study investigates the influence of synthesis processes such as sonication, sol-gel, and microwave on the production of highly crystalline Lanthanum oxide nanoparticles (La₂O₃) employing Lanthanum nitrate and Ammonium hydroxide (NH₄OH) as precursors. X-ray diffraction (XRD), particle size analysis (DLS), Field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible absorption spectroscopy (UV–Vis), and electrochemical impedance spectroscopy (EIS) were used to examine the most effective processing method and its effects on the nanoparticle characteristics, such as structure, morphology, and optical and electrical behavior. Sonication produces La₂O₃ NPs with a smaller crystalline size, an agglomerated nanorod structure, a higher bandgap, and better electrical responsiveness than sol-gel and microwave techniques. Structural and optical characterization tests discovered this. The photocatalytic degradation activity of cationic Safranin and anionic Congo red dye exhibits degradation efficiency of around 90.13% and 89.66%, respectively.     

溶剂热法制备球状Cu2ZnSnS4纳米晶及其表征

通过简单的溶剂热法合成了锌黄锡矿结构的Cu2ZnSnS4(CZTS)纳米晶,使用L-半胱氨酸作硫源和络合剂,以金属氯化物作前驱体,在180°C下反应16h成功获得了CZTS微球.使用X射线衍射(XRD)仪,场发射扫描电子显微镜(FESEM)、能量色散谱(EDS)、高分辨透射电子显微镜(HRTEM)、多功能X射线光电子能谱仪(XPS)、紫外-可见(UV-Vis)分光光度计对产物的物相、结构、形貌及光学性能进行表征.结果表明:所得的产物为纯相锌黄锡矿结构的CZTS纳米颗粒,CZTS微球直径为400-800nm,并可观察到微球是由大量厚度约20nm的纳米片构成;将CZTS颗粒均匀分散在异丙醇中,测试后估算其禁带宽度约1.58eV,与薄膜太阳能电池所需的最佳禁带宽度相近.并对其形成机理进行了初步探讨.     

Tin disulfide nanoflakes decorated with gold nanoparticles for direct electrochemistry of glucose oxidase and glucose biosensing

Previously, we have prepared nanoflake-like tin disulfide (SnS2) and used for the immobilization of proteins and biosensing. We have now modified an electrode with a composite consisting of nanoflake-like SnS2 decorated with gold nanoparticles (Au-NPs) and have immobilized glucose oxidase (GOx) on its surface in order to study its direct electrochemistry. Scanning electron microscopy, electrochemical impedance spectroscopy, Fourier transform IR spectroscopy and cyclic voltammetry were used to examine the interaction between GOx and the AuNP-SnS2 film. It is shown that the composite film has a larger surface area and offers a microenvironment that facilitates the direct electron transfer between enzyme and electrode surface. The immobilized enzyme retains its bioactivity and undergoes a surface-controlled, reversible 2-proton and 2-electron transfer reaction, with an apparent electron transfer rate constant of 3.87 s ^-1. Compared to the nanoflake-like SnS2-based glucose sensor, the GOx-based biosensor exhibits a lower detection limit (1.0 :M), a better sensitivity (21.8 mA?M ^-1 ?cm ^-2), and a wider linear range (from 0.02 to 1.3 mM). The sensor displays excellent selectivity, good reproducibility, and acceptable stability. It was successfully applied to reagentless sensing of glucose at ?0.43 V.

SnS_2纳米材料的水热合成及光催化性质(英文)

在不同的表面活性剂和硫源的条件下,采用水热法制备了多种形貌的SnS2纳米材料,详细讨论了反应条件对其形貌和性质的影响,并采用X射线衍射(XRD)、扫描电镜(SEM)、和BET比表面积法对制备的样品的物相、形貌和组成进行了表征,通过光催化降解罗丹明B研究了所得样品的光催化性能。结果表明:表面活性剂和硫源对产物的结构和形貌起到了重要的作用。当Sn4+与表面活性剂的物质量的比为1∶1时,样品均为纯的六方相SnS2。采用柠檬酸三钠为表面活性剂、硫脲为硫源时制得的SnS2纳米片具有最大的比表面积,同时表现出了最优的光催化性能。     

有序介孔碳CMK-3微波负载NiO及其电容性能研究

微波法负载具有简便、快速、均匀的优点. 本文尝试以乙二醇为还原剂, Ni(Ac)₂为Ni源, 通过微波辐射负载及低温空气煅烧在CMK-3上形成NiO. 对样品进行X射线衍射(XRD)、透射电子显微镜(TEM)、N₂吸脱附等结构表征及循环伏安(CV)等电化学性能测试. 结果显示, 微波法并经低温空气煅烧后有序介孔碳CMK-3的小角XRD峰强度变弱、比表面积下降、孔容减小, 但却使其比电容从229.3 F/g提高到295.9 F/g, 大于文献报导中介孔碳负载MnO₂, RuO₂•xH₂O后的比电容值. 由此说明微波法是有效的负载方法, 具有较好的应用前景.     

Electrochemical deposition and characterization of SnS thin films

Thin films of SnS were cathodically deposited onto stainless steel substrates from bath containing 0.025 M SnSO₄, 0.25 M KSCN and 0.25 M Na₂SO₄. The mechanism of electrochemical co-deposition of tin and sulphur was investigated by cyclic voltammetry. Analysis of the chronoamperometric current–time transients suggested that, in the potential range −560 to −590 mV vs saturated calomel electrode, the electrodeposition of SnS involved progressive nucleation model. However, at a potential −600 mV, the electrodeposition involved instantaneous nucleation model. The deposits have been characterized by scanning electron microscopy, X-ray diffraction and optical measurements. SnS films were found to be polycrystalline with an optical energy gap of 1.38 eV.     

High visible light-driven photocatalytic activity of large surface area Cu doped SnO<Subscript>2</Subscript> nanorods synthesized by novel one-step microwave irradiation method

The paper investigates the structural, optical and photocatalytic activity of large surface area single crystalline copper (Cu) doped SnO₂ nanorods (NRs) synthesized by a novel one-step microwave irradiation method. Powder X-ray diffraction (XRD) analysis confirms that both pure and Cu doped SnO₂ are tetragonal rutile type structure (space group P42/mnm) formed during the microwave process within 10 min without any post annealing treatment. Transmission electron microscopy (TEM) reveals that the as synthesized Cu doped SnO₂ samples exhibited rod-like shape and the length was less than 80 nm and diameter was about few nanometers. Typical selected-area electron diffraction (SAED) pattern indicates that, the growth direction of Cu–SnO₂ nanorod is along [110] direction. The variety of phonon interaction in the pure and Cu doped SnO₂ is observed by Raman spectroscopy. Electron paramagnetic resonance and X-ray photoelectron spectroscopy (XPS) confirms that the presence of copper and tin as Cu²⁺ and Sn⁴⁺ in state, respectively. The photocatalytic activity was monitored via the degradation of methylene blue (MB) and Rhodamine B (RhB) dyes and the Cu–SnO₂ showed better photocatalytic activity than that of pure SnO₂. This could be attributed to the effective electron–hole separation by surface modification.     

不同形貌和尺寸的锂离子电池SnS负极材料

通过高能球磨、微波辅助合成和化学合成方法制备不同形貌和不同尺寸的SnS材料. 运用X射线衍射和透射电镜对其结构和形貌进行分析. 在透射电镜下观察发现, 所得SnS材料呈现出纳米颗粒、层片和纳米棒状. 电化学测试结果表明, 高能球磨和化学合成(无表面活性剂加入)得到的SnS材料有较好的电化学性能, 在循环40个周期后仍分别有375和414 mAh·g-1 的电化学容量. 纳米级SnS电极材料良好的电化学性能有赖于其紧凑的纳米结构, 一定的形貌及合适的尺寸. 尽管非活性相Li2S可以帮助维持SnS电极在充放电过程中的稳定结构, 但SnS的形貌及尺寸才是获得良好电化学性能的SnS电极的关键因素.     

A study of the effect of the synthesis conditions of titanium dioxide on its morphology and cell toxicity properties

In this study, titanium dioxide nanoparticles (NPs) were synthesized using the home microwave method, and the effect of the microwave irradiation time on the structure of NPs was investigated. In addition, the morphological effect of these NPs on the toxicity of HDMSCs cells was investigated. The crystalline structure and morphology of the NPs were analyzed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FE-SEM); the cytotoxicity was determined by the methyl thiazolyl tetrazolium (MTT) assay. X-ray diffraction analysis revealed that all thin films had a polycrystalline nature with an anatase phase of TiO₂. It was also found that the crystallite size increased with increasing microwave radiation time. The FTIR spectrum showed Ti-O-Ti properties by the peak in the range between 527 and 580 cm^?1. Further, the FE-SEM images showed that the grain size increased with increasing irradiation time. The MTT assay results showed that the accumulation of NPs leads to toxicity.     

超薄Co3O4纳米片薄膜制备及其电化学传感器性能

本文以电沉积的金属钴薄膜作为原材料,通过简单的氧化技术获得了薄膜前驱体材料,并进一步在350 ^oC热处理条件下获得了超薄Co₃O₄纳米片薄膜材料. 通过扫描电镜（SEM）,X-射线衍射（XRD）,透射电镜（TEM）等手段对材料的物理结构进行了深入分析,并通过循环伏安法（CV）表征了该薄膜材料的电化学活性. 作为电化学传感器件的活性材料,该薄膜材料对H₂O₂的检测表现出较宽的线性浓度检测范围（0 ~ 4 mmol•L^-1）和较高的电流响应(~ 1.15 mA•cm^-2),在该领域具有较高的应用价值.     

Development and Properties of Surfactant‐Free Water‐Dispersible Cu2ZnSnS4 Nanocrystals: A Material for Low‐Cost Photovoltaics

A simple, yet novel hydrothermal method has been developed to synthesize surfactant‐free Cu₂ZnSnS₄ nanocrystal ink in water. The environmentally friendly, 2–4 nm ultrafine particles are stable in water for several weeks. Detailed X‐ray diffraction (XRD) and high‐resolution transmission electron microscopy revealed the formation of single‐crystalline‐kesterite‐phase Cu₂ZnSnS₄. Elemental mapping by scanning electron microscopy/energy dispersive spectrometry corroborated the presence of all four elements in a stoichiometric ratio with minor sulfur deficiency. Finally, Raman spectroscopy ruled out the possible presence of impurities of ZnS, Cu₂SnS₃, SnS, SnS₂, Cu_2?xS, or Sn₂S₃, which often interfere with the XRD and optical spectra of Cu₂ZnSnS₄. X‐ray photoelectron spectroscopic studies of the as‐synthesized samples confirmed that the oxidation states of the four elements match those of the bulk sample. Optical absorption analyses of thin film and solution samples showed high absorption efficiency (>10⁴ cm^?1) across the visible and near‐infrared spectral regions and a band gap E_g of 1.75 eV for the as‐synthesized sample. A non‐ohmic asymmetric rectifying response was observed in the I–V measurement at room temperature. The nonlinearity was more pronounced for this p‐type semiconductor when the resistance was measured against temperature in the range 180–400 K, which was detected in the hot‐point probe measurement.     

Structural and optical behavior of SnS2/NiFe2O4 NCs prepared via novel two-step synthesis approach for MB and RhB dye degradation under sun light irradiation

The present investigation focuses on facile two-step synthesis approach fabrication of tin sulfide (SnS₂)/ nickel ferrite (NiFe₂O₄) nanocomposites (NCs) for the first time. The crystallinity and phase purity of the prepared material was investigated in powder X-ray diffraction (PXRD) studies. The presence of functional groups (stretching and bending vibration) was primarily determined by the Fourier Transform Infrared Spectroscopy (FT-IR) analysis. As well as, optical behavior of the synthesized samples was determined in UV–Vis absorption spectroscopic studies, and the presence of surface defects was established by PL spectroscopic studies. From the FESEM analysis, sponge-like structure was attained and Ni, Fe, Sn, S and O elemental component was determined by the EDAX spectrum analysis. The as-prepared SnS₂/NiFe₂O₄ NCs exhibit superior photocatalytic performance and high stability toward the reduction of methylene blue (MB) and rhodamine B (RhB) dyes under irradiation of direct sunlight. The synthesized nanocomposites showed an efficient photocatalytic activity with a high reaction kinetic rate.

     

Effet Mössbauer de 119Sn dans les systèmes SnSBaS et SnSTl2S

Tin-119 Mössbauer spectra have been recorded at liquid nitrogen and room temperatures for ternary sulfides isolated from the systems SnSBaS and SnSTl₂S. The chemical isomer shifts observed (2.8 – 3.4 mm/sec relative to BaSnO₃ at 293 K) are characteristic of divalent tin compounds. The data are consistent with the known structures of these compounds and are discussed with regard to the stereochemical activity of the tin(II) lone pair of electrons. For Tl₂Sn₂S₃ and Tl₄SnS₃ the Mössbauer parameters are interpreted in terms of direct population of conductance bands by nonbonding electron pairs.