Showing papers in "Inorganic chemistry frontiers in 2016"

Nanozymes in bionanotechnology: from sensing to therapeutics and beyond

Abstract: In the past few decades, researchers have developed lots of artificial enzymes with various materials to mimic the structures and functions of natural enzymes. Recently, nanozymes, nanomaterials with enzyme-like characteristics, are emerging as novel artificial enzymes, and attracting researchers’ enormous interest. Remarkable advances have been made in the area of nanozymes due to their unique properties compared with natural enzymes and classic artificial enzymes. Until now, lots of nanomaterials have been studied to mimic various natural enzymes for wide applications. To highlight the recent progress of nanozymes (especially in bionanotechnology), here we discuss the diverse applications of nanozymes, which range from sensing, imaging, and therapeutics, to logic gates, pollutant removal, water treatment, etc. Finally, we address the current challenges facing nanozyme research as well as possible directions to fulfill their great potential in future.

Two-dimensional layered nanomaterials for gas-sensing applications

Abstract: Owing to the unique thickness dependent physical and chemical properties, two-dimensional (2D) layered nanomaterials have received tremendous attention and shown great potential in the fabrication of high-performance electronic/optoelectronic devices. Notably, the implication of 2D nanomaterials in the gas-sensing field has also drawn considerable attention but few related review studies have been reported. This critical review mainly focuses on the current progress of 2D layered nanomaterials in gas-sensing applications. Firstly, we describe the basic attributes of 2D layered nanostructures and discuss the fundamentals of their gas-sensing applications. Secondly, we have numerated recent gas-sensing studies on typical 2D layered nanomaterials, including graphene, MoS2, MoSe2, WS2, SnS2, black phosphorus, and others. Particularly, the optimized strategies for improving their gas-sensing performances are also discussed here. Finally, we conclude this review with some perspectives and the outlook on future advances in this field.

Challenges and recent advances in MOF–polymer composite membranes for gas separation

Abstract: Membrane technology has attracted tremendous attention in the field of gas separation due to its low cost and energy consumption. Polymer membranes are used in some industrial-scale gas separation processes, however, they often suffer a trade-off between permeability and selectivity. To overcome this limitation, porous materials with molecular sieve properties have been combined with polymers to give membranes with enhanced gas separation performance. Metal–organic frameworks (MOFs) are nanoporous materials possessing ultrahigh porosity, large surface area, structural diversity and rich functionalities, which make them promising candidates for gas separation. This review primarily focuses on the fabrication methods of MOF–polymer composite membranes including MOF-based mixed-matrix membranes (MMMs) and polymer supported MOF membranes. Recent progress in MOF membrane fabrication, incorporating the challenges and difficulties faced, are presented. Furthermore, corresponding solutions and strategies are given in detail to offer instructions to fabricate membranes with ideal morphology and performance.

High performance electrochemical capacitor materials focusing on nickel based materials

Abstract: Of the two major capacitances contributing to electrochemical storage devices, pseudo-capacitance, which results from the reversible faradaic reactions, can be much higher than the electric double layer capacitance. Transition metal compounds are emerging electrode materials for pseudo-capacitors due to their multiple oxidation states and different ions. As one of the most well-known electroactive inorganic materials, nickel based materials are being developed for this purpose. Nickel based materials have been intensively investigated and evaluated as potential electrode materials for pseudo-capacitors due to their thermal stability and chemical stability, high theoretical specific capacity, low price and environment friendliness. A variety of synthetic methods such as hydrothermal/solvothermal methods, sol–gel, electrodeposition, and the spray deposition method have been successfully applied to prepare nickel based compounds and composite materials. In this review, comprehensive summaries and evaluations have been given to show the recent progress. And we introduce the nickel based compounds and composites electrode materials for supercapacitors via synthesis methods, the electrochemical performances of the electrode materials and the devices.

Cobalt nitrides as a class of metallic electrocatalysts for the oxygen evolution reaction

Abstract: The development of highly-efficient, stable and cost-effective electrocatalysts for the oxygen evolution reaction (OER) is critical for a range of renewable-energy technologies, including metal–air batteries, fuel cells and water-splitting reactions. However, most of the well-developed electrocatalysts are semiconductors or insulators with poor conductivity, which has profoundly inhibited their overall OER efficiency. In this study, metallic cobalt nitrides (Co2N, Co3N and Co4N) arising from electron delocalization modulation have been investigated for OER electrocatalysts in alkaline solution for the first time. Benefiting from the synergistical engineering of the electrical conductivity and nitrogen content, the simple metallic Co4N catalyst without modifications exhibits a stable current density of 10 mA cm−2 at a small overpotential of 330 mV for OER with a Tafel slope as low as 58 mV dec−1 in alkaline medium, which is superior to most of the unmodified metal oxide electrocatalysts reported to date. Our finding introduces new possibilities for the design of highly active electrocatalysts using synergistical electrical conductivity regulation and composition modulation.

An overview of the modification of g-C3N4 with high carbon containing materials for photocatalytic applications

Abstract: In recent years, graphitic carbon nitride has become one of the very exciting sustainable materials, due to its unusual properties and promising applications as a heterogeneous catalyst in water splitting and organic contaminant degradation. A variety of modifications have been reported for this nanostructured material with the use of carbonaceous materials to enhance its potential applications. This review summarizes the ongoing developments towards the use of carbonaceous materials like activated carbon (AC), ordered mesoporous carbon (OMC), carbon nanotubes (CNTs), fullerene (C60) and graphene (GE) for the enhancement of the photocatalytic performance of metal free semiconductor photocatalysts because of their special structures and unique electronic properties. Also this review highlights the recent strategies aiming to promote the activity by coupling with polymers (having higher carbon content). Our study reveals that in addition to the charge transfer effects, morphological changes in g-C3N4 are also introduced by combination of g-C3N4 with carbonaceous materials to tailor its pristine properties and to extend its applications.

Intercalation in two-dimensional transition metal chalcogenides

Abstract: Intercalation is a reversible insertion process of foreign species into crystal gaps. Layered materials are good host materials for various intercalant species ranging from small ions to atoms to molecules. Given the recent intense interest in two-dimensional (2D) layered materials in thin limits, this review highlights the opportunities that intercalation chemistry can provide for nanoscale layered materials. Novel heterostructures or emergent electrical properties not found in the intrinsic host materials are possible with intercalation. In particular, we review various exfoliation methods developed for 2D layered nanomaterials based on intercalation chemistry and extensive tuning of the electrical, optical, and magnetic properties of 2D layered materials due to intercalation.

A review of metal oxynitrides for photocatalysis

Abstract: Photocatalytic hydrogen (H2) production represents a very promising but challenging contribution to a clean, sustainable and renewable energy system. Photocatalytic water splitting into hydrogen and oxygen is a method to directly convert solar energy into storable chemical energy, and has received considerable attention for use in large scale solar energy utilization because of its great potential for low cost and clean energy production. Developing efficient and cost-effective photocatalysts for water splitting is a growing need, and semiconductor photocatalysts have recently attracted more attention due to their stability and simplicity. Over the past few decades, various metal oxide photocatalysts for water splitting have been developed and their photocatalytic application studied under UV irradiation. To harness solar energy efficiently, a recent main concern has been the development of visible-light (λ > 400 nm) active photocatalysts for water splitting. Metal oxynitrides are emerging materials that may exhibit the properties of both oxides and nitride. Metal oxynitride photocatalysts are of significant interest in the field of photocatalytic water splitting as the observed small band gaps lead to activity in the visible range. Titanium, tantalum, niobium, gallium and zirconium form important photocatalysts which show promise in visible light-driven photoreactions. Along with perovskite structures, development of double complex perovskite oxynitrides that are active under visible light are also reviewed. This review article provides a broad overview of the development of water-splitting photocatalysts for generating hydrogen, summarizing the current state of work with a focus on the recent progress in visible-light induced overall water splitting on oxynitride photocatalysts.

Recent developments in the catalytic hydrogenation of CO2 to formic acid/formate using heterogeneous catalysts

Abstract: The conversion of CO2 into value added chemicals is one of the fascinating strategies to mitigate the level of CO2 in the atmosphere. Specifically, the hydrogenation of CO2 into formic acid/formate has received a great deal of attention since the product is a valuable basic chemical as well as a promising energy storage material. However due to the kinetic and thermodynamic limitations of this conversion, developing an efficient catalytic system has become desirable. Therefore various approaches have been implemented for the development of both homogeneous and heterogeneous catalysts. In this context, recent advances in the hydrogenation of CO2 to formic acid/formate using heterogeneous catalysts as well as theoretical investigations are presented.

Rational design of semiconductor-based photocatalysts for advanced photocatalytic hydrogen production: the case of cadmium chalcogenides

Abstract: Semiconductor-based photocatalytic hydrogen (H2) production from water has recently received considerable attention because of its enormous potential for solving worldwide ever-increasing energy crises and environmental issues. Among various semiconductors, cadmium chalcogenides (CdX, X = S, Se, Te), with a variety of superior properties including appropriate bandgaps for visible-light absorption, proper conduction band edge potentials for water reduction and abundant reserves on the earth, have fuelled great interest in exploring their photocatalytic properties for solar-driven H2 production from water. This review article summarizes the recent progress in developing CdX-based photocatalyst systems for the production of H2 from solar water splitting. The basic mechanistic fundamentals of CdX photocatalysts and various strategies to enhance the activity and stability of this class of photocatalysts are introduced in detail. Finally, some key scientific issues and prospective directions in this area of research are also discussed.

Binary nickel–iron nitride nanoarrays as bifunctional electrocatalysts for overall water splitting

Abstract: Electrochemical water splitting provides a facile method for high-purity hydrogen production, but electro-catalysts with a stable bifunctional activity towards both oxygen and hydrogen evolution have been rarely developed. Herein we report a Fe2Ni2N material with a vertically aligned nanoplate array architecture as a bifunctional catalyst for overall water splitting in an alkaline environment. This advanced catalyst affords small onset overpotentials and fast current density increase, resulting in an excellent water splitting performance (requiring 1.65 V for achieving 10 mA cm−2), superior to the combination of benchmark noble metal catalysts.

Defect-driven oxygen reduction reaction (ORR) of carbon without any element doping

Abstract: A porous carbon (PC) material, containing carbon and oxygen only, was synthesized via carbonisation of a Zn-MOF (IRMOF-8) at 950 °C. Interestingly, the derived materials of this reaction exhibit excellent electrocatalytic activity, molecular selectivity and long-term durability. The fact that this material, which is effectively a “pure” carbon, lacking any elemental doping, exhibits excellent oxygen reduction reaction (ORR) activity suggests that a mechanism not dependent on elemental doping is being utilised. We suggest the formation of defects arising from the removal of Zn atoms as a consequence of the calcination procedure play the critical role in this process.

Modulating single-molecule magnet behaviour of phenoxo-O bridged lanthanide(III) dinuclear complexes by using different β-diketonate coligands

Abstract: Three dinuclear Dy(III) complexes, [Dy2(tfa)4L2] (1), [Dy2(TTA)4L2] (2) and [Dy2(dbm)4L2·2CH3CN·0.5H2O] (3) (tfa = trifluoroacetylacetonate, TTA = 2-thenoyltrifluoroacetone, dbm = dibenzoylmethane and HL = 2-[((4-bromophenyl)-imino)methyl]-8-hydroxyquinoline, have been synthesized, and structurally and magnetically characterized. The Dy(III) ions are eight-coordinated with two bidentate β-diketonate and two μ2-O bridging 8-hydroxyquinoline Schiff base ligands. Magnetic studies reveal that 1–3 exhibit different magnetic relaxation behaviors with the anisotropic barriers of 9.61 K (1), 54.81 K (2) and 30.98 K (3), respectively. The different magnetic relaxation behaviors of the three Dy2 complexes originate from the different chemical environments of the central Dy3+ ions with different β-diketonate coligands.

Ruthenium(II) arene complexes containing benzhydrazone ligands: synthesis, structure and antiproliferative activity

Abstract: A suitable method for the synthesis of ruthenium(II) arene benzhydrazone complexes (1–6) of the general formula [(η6-arene)Ru(L)Cl] (arene-benzene or p-cymene; L-monobasic bidentate substituted 9-anthraldehyde benzhydrazone derivatives) has been described. The composition of the complexes has been established by elemental analysis, IR, UV-Vis, emission, NMR and ESI-MS spectral methods. The solid state molecular structure of a representative complex was determined by a single-crystal X-ray diffraction study and indicates the presence of pseudo-octahedral (piano stool) geometry. All the complexes have been thoroughly screened for their cytotoxicity against human cervical cancer cells (HeLa), human breast cancer cell line (MDA-MB-231) and human liver carcinoma cells (Hep G2) under in vitro conditions. Interestingly, the cytotoxic activity of complex 6 is much more potent than cisplatin with low IC50 values against all the cancer cell lines tested. Furthermore, the results of AO–EB, Hoechst 33258 and flow cytometry analyses reveal that these complexes induce cell death only through apoptosis. The comet assay has been employed to determine the extent of DNA fragmentation in cancer cells. A hemolysis assay with human erythrocytes demonstrated good blood biocompatibility of all the ruthenium(II) arene benzhydrazone complexes. These results highlight the strong possibility to develop highly active ruthenium complexes as anticancer agents.

Reduction of thermal conductivity through nanostructuring enhances the thermoelectric figure of merit in Ge1−xBixTe

Abstract: A promising thermoelectric figure of merit, zT, of ∼1.3 at 725 K was obtained in high quality crystalline ingots of Ge1−xBixTe. The substitution of Bi3+ in a Ge2+ sublattice of GeTe significantly reduces the excess hole concentration due to the aliovalent donor dopant nature of Bi3+. Reduction in carrier density optimizes electrical conductivity, and subsequently enhances the Seebeck coefficient in Ge1−xBixTe. More importantly, a low lattice thermal conductivity of ∼1.1 W m−1 K−1 for Ge0.90Bi0.10Te was achieved, which is due to the collective phonon scattering from meso-structured grain boundaries, nano-structured precipitates, nano-scale defect layers, and solid solution point defects. We have obtained a reasonably high mechanical stability for the Ge1−xBixTe samples. The measured Vickers microhardness value of the high performance sample is ∼165 HV, which is comparatively higher than that of state-of-the-art thermoelectric materials, such as PbTe, Bi2Te3, and Cu2Se.

Recent advances in iron-catalysed cross coupling reactions and their mechanistic underpinning

Abstract: Advances in iron-catalysed cross coupling from 2010–2015 are critically reviewed. In addition to a description of the systems that have emerged since 2010, the significant mechanistic work carried out to understand the mechanisms of these transformations will be discussed. An emphasis will be placed on mechanistic studies that utilize in situ reaction monitoring and the tools used to achieve this goal.

Novel nanoporous carbon derived from metal–organic frameworks with tunable electromagnetic wave absorption capabilities

Abstract: Nanoporous carbon materials derived from metal organic frameworks (MOFs) have attracted considerable attention due to their low density for microwave absorption. Nevertheless, their poor impedance matching has reduced the absorber performance. The design and fabrication of complex nanocarbon materials with outstanding impedance matching is still a challenge. Here, we prepared a core–shell structured ZIF-8@ZIF-67 crystal through a new seed-mediated growth method. After the thermal treatment of ZIF-8@ZIF-67 crystals, we obtained selectively nanoporous carbon materials consisting of ZnO/NPC as the cores and highly graphitic Co/NPC as the shells. The shell thicknesses of ZIF-67 can be tuned simply by varying the feeding molar ratios of Co2+/Zn2+. The composites exhibited excellent impedance matching and strong absorption. The composite ZnO/NPC@Co/NPC-0.5 samples filling with 50 wt% of paraffin show a maximum reflection loss (RL) of −28.8 dB at a thickness of 1.9 mm. In addition, a broad absorption bandwidth for RL <−10 dB which covers from 13.8–18 GHz can be obtained. Our study not only bridges diverse carbon-based materials with infinite metal–organic frameworks but also opens a new avenue for artificially designed nano-architectures with target functionalities.

Recent developments of iron pincer complexes for catalytic applications

Abstract: Iron catalysis is attractive for organic synthesis because iron is inexpensive, abundant, and non-toxic. To control the activity and stability of an iron center, a large number of iron pincer complexes have been synthesized. Many such complexes exhibit excellent catalytic activity in a number of important organic reactions such as hydrogenation, hydrosilylation, dehydrogenation, and carbon–carbon bond forming reactions. In this review, recent examples of representative iron pincer catalysts are presented.

Nanoparticles of chitosan conjugated to organo-ruthenium complexes

Abstract: The synthesis of nanoparticles of conjugates of caffeic acid-modified chitosan with ruthenium arene complexes is described. The chemical structure and physical properties of the nanoparticles were characterised by electronic absorption spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FT-IR), 1H NMR spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and circular dichroism (CD) analysis. The multi-spectral results revealed that caffeic acid is covalently bound to chitosan and chelates to {Ru(p-cymene)Cl}+. The DLS studies indicated that the Ru–caffeic acid modified chitosan nanoparticles are well-defined and of nanometre size. Such well-defined nanocomposites of chitosan and metal complexes might find a range of applications, for example in drug delivery. Introduction to the international collaboration Yanqing Wang from Yancheng Teachers University, People's Republic of China is developing a research programme in the exciting area of medicinal inorganic chemistry, and in particular the design of nanoparticles for the delivery of metal anticancer complexes. He was awarded a research fellowship from the Jiangsu Overseas Research & Training Program for University Prominent Young & Middle-aged Teachers and President to spend the year from February 2014 to February 2015 in the laboratory of Peter Sadler at the University of Warwick, UK. There he carried out research in bioinorganic chemistry on topics related to the design and synthesis of nanoparticle conjugates of natural polymers with organo-ruthenium complexes. He synthesised nanocomposites of caffeic acid-modified chitosan linked to ruthenium arene complexes. Chitosan is deacetylated chitin, found in the exoskeleton of crustaceans and cell walls of fungi. Such well-defined nanocomposites of chitosan and metal complexes might find a range of applications, for example in drug delivery.

Rapid, green and inexpensive synthesis of high quality UiO-66 amino-functionalized materials with exceptional capability for removal of hexavalent chromium from industrial waste

Abstract: We describe a new synthetic method for the isolation of the UiO-66 amino-functionalized material (called metal organic resin-1, MOR-1) and its composite with alginic acid (HA). MOR-1 can be prepared in high yield (∼70%) and purity within an hour via a reflux reaction of ZrCl4 and 2-amino-terephthalic acid in acifidied aqueous solution, whereas addition of sodium alginate to the fine suspension of MOR-1 resulting from the reflux synthesis affords the MOR-1-HA composite. This inexpensive, green and fast preparation method results in UiO-66 amino-functionalized materials (MOR-1 and MOR-1-HA) of the same quality and microporous features as those of compounds isolated with the slower solvothermal synthesis involving toxic and costly organic solvents. Field Emission-Scanning Electron Microscopy (FE-SEM) studies revealed that MOR-1 consists of spongy nanoparticles (150–300 nm in size), whereas MOR-1-HA nanoparticles are relatively compact. Thus, for the first time we could visualize the effect of alginic acid partially coating the surface of the MOR particles. The composite prepared by this method can be successfully utilized as a stationary phase, mixed with sand, in an anion-exchange column. The column shows excellent hexavalent chromium sorption properties and can be easily regenerated and reused several times with almost no loss of its initial Cr(VI) removal capacity. Remarkably, this ion exchange column is capable of eliminating Cr(VI) ions from chrome plating wastewater samples, thus indicating its potential for applications in industrial wastewater treatment.

Nanocrystalline iron oxide based electroactive materials in lithium ion batteries: the critical role of crystallite size, morphology, and electrode heterostructure on battery relevant electrochemistry

Abstract: The importance of crystallite size control and direct synthesis of materials with desirable properties is broadly applicable for the rational design and development of new active materials for energy storage. Recently, the use of nanoparticles and crystallite size control has redefined electrode design strategies, due in part to the large surface area/volume ratios providing more pathways for ion movement within the bulk electrode. This review is structured primarily as a case study, where reports involving a specific densely structured iron oxide, magnetite, Fe3O4, and its use as an electrode in LIBs are used as examples. Due to the high theoretical capacity (924 mA h g−1), and opportunity for implementation of a low cost electrode material, magnetite was selected as the model material for this review. Notably, crystallite size, morphology, and electrode heterostructure can all play a critical role in battery relevant electrochemistry, particularly for crystallographically dense materials such as Fe3O4. Several examples of Fe3O4 based composites are described, incorporating different types of conductive materials such as carbons as part of the structure. Additionally, this review also provides a brief introduction to a newer iron oxide based material with a 2D layered structure, silver ferrite, where crystallite size control was synthetically achieved. By focusing on two specific iron oxide based nanoscale inorganic materials, this review highlights and distinguishes the contributions of electroactive material crystallite size, morphology and electrode heterostructure to electrochemical behavior, facilitating the future development of next generation of battery electrodes.

Facile synthesis of amorphous aluminum vanadate hierarchical microspheres for supercapacitors

Abstract: Micro-nanostructured mixed metal vanadates have recently garnered enormous attention owing to their remarkable performances in catalysis, energy storage and conversion. In this work, we report the synthesis of amorphous aluminum vanadate hierarchical microspheres via a simple hydrothermal approach with polyvinylpyrrolidone as a surface directing agent. Amorphous aluminum vanadate hierarchical microspheres are firstly described as a kind of electrode material for supercapacitors. The measured specific capacitance of the amorphous aluminum vanadate electrode is 497 F g−1 at 1 A g−1 with good stability and a retention capacity of 89% after 10 000 cycles. In addition, the fabricated asymmetric supercapacitor device delivered better performance with an extended operating voltage window of 1.5 V, excellent cycle stability (10 000 cycles, 85% capacitance retention), high energy density (37.2 W h kg−1 at 1124.4 W kg−1) and high power density (11 250 W kg−1 at 25 W h kg−1). This study essentially offers a new kind of vanadate as an electrochemical active material for the development of supercapacitors.

The construction, structures, and functions of pillared layer metal–organic frameworks

Abstract: Pillared layer metal–organic frameworks (PL-MOFs), belonging to one representative of porous materials, have witnessed major advances in the past few years. They can be classified into subsets – 3D pillared layers, 2D pillared bilayers, and interpenetrated and interdigitated layers. By choosing the molecular structures and chemical properties of the modular organic ligands used in PL-MOFs, high porosity and large internal surface areas can be achieved, while the shape, size, and surface of the channels can be modified to enhance their physical properties. The structural flexibility and response to different guests and external physical stimuli render PL-MOFs good candidates for investigating solid state structural transformations and reactions. In this review, we explore how modular ligand design leads to various PL-MOFs. The importance of PL-MOFs will be highlighted by their special functions including magnetism, sorption, separation, sensing, catalysis etc. We will also introduce recent findings on PL-MOFs in dynamic structural transformations, step-by-step assembly, and preparation of hybridized MOFs and nano-films. Introduction to the international collaboration Our collaborative work started in earnest after our meeting at ICMM2010 in Beijing. The complementarity of the interests of our two groups led to a successful development of the chemistry and physics of metal–organic frameworks and clusters, involving the design, elaboration, characterization and studies of the structural and physical properties of the novel materials. In particular, studies were directed at multi-functionalities such as structural properties, electrical conductivity, magnetism and in some cases optical properties. In the six years of this collaborative work, funded by the Guangxi Province (China) and the CNRS (France), 22 papers have been published, several in high-impact factor journals and citations exceeding 700. As well as excelling on the international level, the groundwork has been the development of students. The present review is a collection of materials with one common interest in the area concerned with layered structures and their properties and presented in the context of what are present-day studies internationally.

Multi-shelled LiMn2O4 hollow microspheres as superior cathode materials for lithium-ion batteries

Abstract: Owing to its environmental-benignity, low-cost and abundance, spinel LiMn2O4 has long been considered as a promising cathode material for lithium-ion batteries (LIBs). However, the low electronic conductivity, small lithium diffusion coefficient and poor capacity retention hindered its further development and application. Herein, we report the synthesis of multi-shelled LiMn2O4 hollow microspheres through a hard template method, with the composition, shell number, shell thickness and porosity accurately controlled. Benefitting from the structural superiorities of multi-shelled hollow structures, the triple-shelled LiMn2O4 hollow microsphere exhibits a better cycling stability than all the reported results based on un-coated or un-doped LiMn2O4 (the capacity fading rate is 0.10% per cycle).

Mixed-anion templated cage-like lanthanide clusters: Gd27 and Dy27

Abstract: Two nanoscale clusters whose metals are exclusively lanthanides, and whose formulas are [(ClO4)@Ln27(μ3-OH)32(CO3)8(CH3CH2COO)20(H2O)40]·(ClO4)12·(H2O)50 (abbreviated as Ln27. 1, Gd; 2, Dy), were synthesized. Structural analysis showed that the 27 lanthanide ions were organized into a beautiful cage-like structure templated by eight CO32− groups, which were generated from the fixation of atmospheric CO2. Acting as a template guest, one ClO4− group was encapsulated in the Ln27 cage. The Ln27 compound is by far the largest odd-numbered lanthanide cluster synthesized to date. In magnetization studies of these two compounds, isotropic Gd27 exhibited a large MCE of 41.8 J kg−1 k−1 at 2 K for ΔH = 7 T, while anisotropic Dy27 displayed a slow relaxation of its magnetization.

(Boratabenzene)(cyclooctatetraenyl) lanthanide complexes: a new type of organometallic single-ion magnet

Abstract: A series of new sandwich type lanthanide complexes containing both boratabenzene and cyclooctatetraenyl ligands, [(C5H5BR)Ln(COT)] (1Er: R = H, Ln = Er; 2Er: R = Me, Ln = Er; 3Er: R = NEt2, Ln = Er; 4Dy: R = H, Ln = Dy; 5Dy: R = Me, Ln = Dy; 6Dy: R = NEt2, Ln = Dy; 7Y: R = NEt2, Ln = Y), were synthesized. The structures of 1Er–7Y were all characterized by single crystal X-ray diffraction. Dynamic susceptibility experiments showed that the erbium complexes 1Er–3Er exhibited slow magnetic relaxation under zero dc field while the dysprosium complexes 4Dy–6Dy did not. For the erbium complexes, the magnetic properties were influenced by the substituent on the boron atom. 1Er exhibited hysteresis up to 8 K, and 2Er featured the highest energy barrier (300 cm−1) among all the reported erbium single-ion magnets (SIMs). The influence of the boron substituent on the magnetic properties was highlighted by ab initio calculations.

MoS2 with an intercalation reaction as a long-life anode material for lithium ion batteries

Abstract: MoS2 with expanded layers was synthesized and characterized as an anode material for lithium ion batteries in an ether-based electrolyte by cutting off the terminal discharge voltage at 1.0 V to prevent a MoS2 conversion reaction. The as-prepared MoS2 achieved 96% capacity retention even after 1400 cycles and showed good performance in a full cell with LiCoO2 as the counter electrode.

A new methylviologen-templated zinc gallophosphate zeolite with photo-/thermochromism, fluorescent and photoelectric properties

Abstract: A new zinc gallophosphate zeolite [Zn5.8Ga14.2(PO4)20F3.2(H3O)3]|C12H14N2|3·3H2O (noted as JU104) with a USI zeotype structure has been solvothermally synthesized by using in situ generated methylviologen (MV) as the template. JU104 has two-dimensional interconnected 12-ring and 10-ring channels running along the [100] and [00] direction, respectively. It exhibits dual thermochromism and photochromism with a broad photo-response range (UV light to visible light) and a long-lived charge-separated state, as well as variable fluorescent and photoelectric properties. Moreover, the multi photo/thermo-induced colors occurring in JU104 make it unusual as compared to other inorganic photo/thermochromism compounds. The MV-templated JU104 zeolite may function as a new efficient electron-transfer system for potential applications in photo/thermochromism and solar energy conversion.

Glutathione modified carbon-dots: from aggregation-induced emission enhancement properties to a “turn-on” sensing of temperature/Fe3+ ions in cells

Abstract: In this paper, a novel “turn-on” chemosensor for detecting temperature and Fe3+ has been designed. This nanosensor is based on the aggregation-induced emission enhancement (AIEE) properties of fluorescent carbon dots (CDs). The CDs prepared by a facile hydrothermal route show blue emission (λem = 505 nm) with a quantum yield of 4.7%. The resultant CDs are modified by glutathione (GSH) on the surface through the carbodiimide-activated coupling reaction. The as-prepared GSH-CDs show good dispersion, high fluorescence and AIEE phenomenon. Resultant GSH-CDs would be aggregated by Fe3+ ions in aqueous solution which results in enhanced fluorescence. Therefore, such GSH-CDs would be excellent candidates as fluorescent probes for the label-free detection of Fe3+ ions with a limit of detection of 0.1 μM. Moreover, the PL intensity of GSH-CDs increases progressively with increasing temperature and they could be used in optical thermometry over a wide temperature range (25–80 °C) with small temperature resolution (∼0.5 °C). Using MC3T3-E1 cells as the model, the resultant nanosensor is demonstrated to monitor temperature and Fe3+ ions in cells. Thus, resultant GSH-CDs could be used as a “turn-on” sensor for highly sensitive and selective detection of temperature and Fe3+ ions in aqueous solution and biosystems.

A strategically designed porous magnetic N-doped Fe/Fe3C@C matrix and its highly efficient uranium(VI) remediation

Abstract: With the growing development of the nuclear industry and the peaceful utilization of nuclear energy, the safe treatment and disposal of high-level wastes in nuclear waste management is still a major challenge. Overcoming this issue requires developing highly efficient materials for capturing U(VI) from nuclear wastewater. Herein, magnetic porous microcubes with a graphitic shell and highly dispersed active cores (Fe/Fe3C nanoparticles) are rationally designed and fabricated by simply annealing preformed polydopamine (PDA) coated Prussian blue (PB) microcubes. To assess the sorption properties, sequestration of U(VI) on N-doped metal/metal carbide nanoparticles encapsulated in a carbon matrix (N-doped Fe/Fe3C@C) was systematically investigated using batch experiments. The sorption performance revealed that the N-doped Fe/Fe3C@C samples exhibited highly efficient removal efficiency for U(VI), and the sample prepared at 800 °C (N-doped Fe/Fe3C@C-800) was the best among the series with a maximum sorption capacity of 203 mg g−1. The U(VI) adsorption and reduction by N-doped Fe/Fe3C@C-800 were affected significantly by solution pH and concentrations of bicarbonate and calcium. The main reaction mechanism involved U(VI) reduction into insoluble U(IV) species by Fe0/Fe(II) and trapping the guest U(IV) in the porous carbon matrix, which synergistically promoted U(VI) removal from solution to N-doped Fe/Fe3C@C-800. This study demonstrated the simple synthesis of magnetic N-doped Fe/Fe3C@C derived from metal–organic frameworks and their potential application in U(VI)-contaminated wastewater remediation. Introduction to the international collaboration In 2003, Prof. X. K. Wang and Prof. B. Grambow started their collaboration in nuclear waste management and the environmental behavior of long-lived radionuclides such as the removal of radionuclides from aqueous solutions, the microstructures and species of radionuclides at the molecular level. They have published many papers in international journals such as Environmental Science & Technology and Geochimica et Cosmochimica Acta.