Coordination-Precipitation Synthesis of Metal Sulfide with Phase Transformation Enhanced Reactivity against Antibiotic-Resistant Bacteria

Given the challenge of bacterial resistance to antibiotics, there is an urgent need to develop alternative antibacterial agents. While some metal sulfides are promising candidates against bacterial resistance, their fundamental mechanism of action (MoA) remains unclear. Herein, a “coordination-precipitation” method is developed for the synthesis of a metal sulfide library and the evaluation of antibacterial consistency. Employing ethylenediamine as a coordination agent and thioglycolic acid as a precipitation agent, 12 different metal sulfide nanocrystals following the same procedure are synthesized. Antibacterial assessment reveals that six metal sulfides with bactericidal potency perform a common feature of phase transformation. In particular, in the process of manganese sulfide (MnS) transformation to Mn₃O₄, a highly reactive complex of high-valance manganese (Mn³⁺) and polysulfide (S₃²⁻) accompanied by superoxide is sustainably generated, which synergistically induces bacterial death with a hallmark of lipid peroxidation (named liperoptosis) specifically toward Gram-positive Staphylococcus aureus (S. aureus). In addition, this MoA confers MnS with therapeutic effects superior to vancomycin in a methicillin-resistant S. aureus-infected skin wound model. This study reveals the correlation between phase transformation and the antibacterial MoA of metal sulfides and provides a general fundamental to design a non-antibiotic antibacterial candidate against bacterial resistance.     

Constructing Layered Nanostructures from Non-Layered Sulfide Crystals via Surface Charge Manipulation Strategy

2D non-layered metal sulfides possess intriguing properties, rendering them bright application prospects in energy storage and conversion, however, the synthesis of non-layered metal sulfide nanosheets is still significantly challenging. Herein, a surface-charge-regulating strategy is developed to fabricate microsized 2D non-layered metal sulfides via manipulation of the isoelectric point, which can easily modulate the manner of surface charge arrangement during the growth of crystal nuclei. The result of this strategy are materials that are completely assembled with a preferred orientation but comprise a large lateral size with maintaining atomic thickness. A series of modified sulfides are successfully synthesized, demonstrating that their microarchitectures are shifted in an expected manner. Then, one of these materials, In₄SnS₈, approaches a promising candidate for sodium storage by means of its structural integrity, boosted transfer kinetics, and abundant active sites. The proposed synthetic protocol can open up a new opportunity to explore 2D non-layered materials for energy-related applications.     

液相超声法制备金属硫化物量子点的研究进展

量子点(Quantum Dots,QDs)是一种零维纳米材料,其尺寸小于或接近激子玻尔半径。随着纳米技术的发展,金属硫化物量子点因其独特的光学、电学和磁学性质而受到广泛关注,可将其分为过渡金属硫化物量子点(TMD QDs)、Ⅱ-Ⅵ族量子点及Ⅳ-Ⅵ族量子点等。超声法制备量子点具有高效、环保、易于控制和可扩展性等优点,逐渐成为制备金属硫化物量子点的重要技术之一。金属硫化物量子点有着别于传统体相材料的优异光电特性,在近些年里,其优越而又独特的性能使得在更多的领域中得到了深入的研究和应用,如光电器件、生物成像、光催化等。本文综述了超声法制备不同金属硫化物量子点的研究进展,并对其性质和应用进行了归纳和总结。最后,对超声法制备金属硫化物量子点进行了展望。     

Progress on the controllable synthesis of all-inorganic halide perovskite nanocrystals and their optoelectronic applications

In the past five years,all-inorganic metal halide perovskite(CsPbX3,X=Cl,Br,I)nanocrystals have been intensely studied due to their outstanding optical properties and facile synthesis,which endow them with potential optoelectronic applications.In order to optimize their physical and chemical properties,different strategies have been developed to realize the controllable synthesis of CsPbX3 nanocrystals.In this short review,we firstly present a comprehensive and detailed summary of existed synthesis strategies of CsPbX3 nanocrystals and their analogues.Then,we introduce the regulations of several reaction parameters and their effects on the morphologies of CsPbX3 nanocrystals.At the same time,we provide stability improvement methods and representative applications.Finally,we propose the current challenges and future perspectives of the promising materials.     

Nanoparticles Prepared by Salt Vapor‐Solvent Vapor Cocondensation and Controlled Nucleation: Metal Sulfides (ZnS,CdS, CdSe,PbS), and Metal Halide (LiF). Size,Aggregates, Structures,Digestive Ripening,Superlattices, and Impregnations

A versatile method for the production of gram quantities of nanocrystals of metal sulfides and metal halides has been developed, based on vaporization of the bulk materials followed by controlled nucleation of the molecular vapor species in cold solvent matrices (cocondensate). This approach worked well with ZnS, CdS, CdSe, CdTe, SnS, PbS, and LiF as examples, and is applicable for a large number of semiconductors, ionic salts, as well as metals. Choice of solvent (polar or non‐polar), vaporization rate, and rate of warm‐up of the cocondensate (period of nucleation) allows some control of crystallite size, aggregate size, and surface area. Interestingly, polar solvents lead to smaller nanocrystals, but larger, less porous aggregates. Also, molar mass of the molecular species has an effect on crystallite size, with heavier molecules giving smaller crystals, apparently due to slower migration in the warming cocondensate. Studies of sintering temperature and crystal growth have shown the nanocrystals are quite thermally stable. Addition of ligands, such as thiols, followed by heating in solvent (digestive ripening) has allowed more monodisperse materials to be formed. Finally, this molecular vapor synthesis approach can be used for impregnating semiconductors (CdS, CdSe) of controlled crystal size on solid supports, such as TiO₂ or SiO₂.     

Regular Metal Sulfide Microstructure Arrays Contributed by Ambient‐Connected Gas Matrix Trapped on Superhydrophobic Surface

Controlling the position of metal sulfide architectures is prerequisite and facilitates their device applications in solar cells, light‐emitting diodes, and many other optoelectronic fields. Thanks to ambient‐connected gas network trapped upon superhydrophobic surfaces, H₂S gas can be continuously transported and reacted with metal ions along solid/liquid/gas triphase contact interface. Therefore, precisely positioning metal sulfide microstructure arrays are generated accordingly. The growth mechanisms as well as influencing factors are investigated to tailor the morphology, structure, and chemical composition of these metal sulfide materials. This interface‐mediated strategy can be widely applied to many other metal sulfides, such as PbS, MnS, Ag₂S, and CuS. In particular, heterostructured metal sulfide architectures, such as PbS/CdS concentric microflower arrays, can be generated by stepwise replacement of metal ions inside liquid, exhibiting the advanced applications of this interface‐mediated growth strategy.     

Recent Tactics and Advances in the Application of Metal Sulfides as High-Performance Anode Materials for Rechargeable Sodium-Ion Batteries

The successful development of post-lithium technologies depends on two key elements: performance and economy. Because sodium-ion batteries (SIBs) can potentially satisfy both requirements, they are widely considered the most promising replacement for lithium-ion batteries (LIBs) due to the similarity between the electrochemical processes and the abundance of sodium-based resources. Among various SIB anode materials, metal sulfides are most extensively studied as materials for high-performance electrodes due to the versatility of their synthesis procedure, utilization potential, and high sodiation capacity. Herein, some of the most effective strategies aimed at effectively alleviating the performance shortcomings of these materials from the materials engineering/design perspective are summarized. In terms of facilitating ion transport in SIBs, which represents one of the most critical aspects of their performance, a specific family of strategies related to a particular operational mechanism is considered rather than categorizing based-on individual sulfide materials. In the foreseeable future, the development of highly functional SIBs electrode materials and utilization of metal sulfides will become highly relevant due to their stability and performance characteristics. Therefore, it is anticipated that this review will guide further research and facilitate the realization of various applications of sulfide-based high-performance rechargeable batteries.     

Simple and Generalized Synthesis of Semiconducting Metal Sulfide Nanocrystals

Uniform‐sized semiconducting nanocrystals of binary metal sulfides are synthesized from the thermolysis of metal‐oleate complexes in alkanethiol. The size of the Cu₂S nanocrystals can be tuned from 7 to 20 nm by varying the reaction conditions. Various shaped nanocrystals of CdS, ZnS, MnS, and PbS are synthesized from the thermal reaction of metal‐oleate complex in alkanethiol.     

General Formation of MS (M = Ni,Cu, Mn) Box‐in‐Box Hollow Structures with Enhanced Pseudocapacitive Properties

Complex hollow structures of metal sulfides could be promising materials for energy storage devices such as supercapacitors and lithium‐ion batteries. However, it is still a great challenge to fabricate well‐defined metal sulfides hollow structures with multi‐shells, hierarchical architectures, and non‐spherical shape. In this work, a template‐engaged strategy is developed to synthesize hierarchical NiS box‐in‐box hollow structures with double‐shells. The NiS box‐in‐box hollow structures constructed by ultrathin nanosheets are evaluated as electrode materials for supercapacitors. As expected, the NiS box‐in‐box hollow structures exhibit excellent rate performance and impressive cycling stability due to their unique nano‐architecture. More importantly, the synthetic method can be easily extended to synthesize other transition metal sulfides box‐in‐box hollow structures. For example, we have also successfully synthesized similar CuS and MnS box‐in‐box hollow structures. The present work makes a significant contribution to the design and synthesis of transition metal sulfides hollow structures with non‐spherical shape and complex architecture, as well as their potential applications in electrochemical energy storage.     

In Situ Construction of 3D Interconnected FeS@Fe3C@Graphitic Carbon Networks for High‐Performance Sodium‐Ion Batteries

Iron sulfides have been attracting great attention as anode materials for high‐performance rechargeable sodium‐ion batteries due to their high theoretical capacity and low cost. In practice, however, they deliver unsatisfactory performance because of their intrinsically low conductivity and volume expansion during charge–discharge processes. Here, a facile in situ synthesis of a 3D interconnected FeS@Fe₃C@graphitic carbon (FeS@Fe₃C@GC) composite via chemical vapor deposition (CVD) followed by a sulfuration strategy is developed. The construction of the double‐layered Fe₃C/GC shell and the integral 3D GC network benefits from the catalytic effect of iron (or iron oxides) during the CVD process. The unique nanostructure offers fast electron/Na ion transport pathways and exhibits outstanding structural stability, ensuring fast kinetics and long cycle life of the FeS@Fe₃C@GC electrodes for sodium storage. A similar process can be applied for the fabrication of various metal oxide/carbon and metal sulfide/carbon electrode materials for high‐performance lithium/sodium‐ion batteries.     

Advanced Catalysts Derived from Composition‐Segregated Platinum–Nickel Nanostructures: New Opportunities and Challenges

Composition segregation, resulting from the rearrangement of atom positions and different enrichment behaviors of different atoms in alloys, has been linked to their enhanced performances in catalytic applications due to the strong electronic effect and largely improved number of available active sites. Hence, composition‐segregated metallic nanostructures have been actively pursued to prepare better‐performing nanocatalysts. Moreover, they also act as an emerging platform to develop unusual nanostructures with desirable functionalities. An overview about the recent advances in preparing unusual nanostructures with desirable functionalities such as highly open 3D structures (concave, frame, porous, etc.) and composites with suitable interfaces (metal–metal, metal–oxide, metal–sulfide, metal–boride, metal–organic, metal–hydroxide interfaces, etc.) based on composition‐segregated metallic nanostructures which can boost heterogeneous catalytic reactions with superior performances is provided here. The different strategies developed so far for the synthesis of composition‐segregated metallic nanostructures are also discussed. Finally, the challenges of the composition‐segregated nanostructure and their functionalized materials are discussed, as well as some perspectives are highlighted on the fine regulation and multifunctionalities of nanostructures, which provide a powerful material foundation for the potential electrocatalysis, organic catalysis, and energy conversion of multicomponent metal nanostructures.     

A Competitive Reaction Strategy toward Binary Metal Sulfides for Tailoring Electromagnetic Wave Absorption

The development of multicomponent dielectric composites has become a mainstream approach for obtaining excellent electromagnetic wave (EMW) absorbers. However, conventional component introduction is often performed blindly and based only on semiempirical rules, lacking precise modulation of components, interfaces, and defects during the reaction process. Herein, a competitive reaction mechanism is proposed for the first time, in which not only the metal ion concentration but also its characteristic are two feasible parameters to control the components, interfaces, and defects to tailor the EMW absorption performances of Cu-based binary metal sulfides. The appropriate heterogeneous interfaces and components and the abundant defects can synergistically benefit the EMW absorption capacity by forming perfect impedance matching and multiple dielectric polarizations. As a result, combined with these advantages, an effective absorption band) of 6.80 GHz (6.3–13.1 GHz) is achieved at 2.80 mm for Cu–Co binary metal sulfide, showing the sole middle-frequency broadband absorption of reported sulfide-based absorbers to date. Other Cu-based binary metal sulfides deliver different EMW absorption behaviors. This work breaks through the limitation of traditional component design, opening up a novel methodology for designing multicomponent composites beyond sulfides with broadband absorption.     

包含双层半导体和金属纳米晶MOS电容的存储特性

制备了包含双层半导体和金属纳米晶的MOS电容结构,研究了其在非挥发性存储器领域的应用。利用真空电子束蒸发技术,在二氧化硅介质中得到了半导体硅纳米晶和金属镍纳米晶。与包含单层纳米晶的MOS电容相比,这种包含双层异质纳米晶的MOS电容显示出更大的存储能力,且保留性能得到改善。说明顶层的金属纳米晶作为一层额外的电荷俘获层可以通过直接隧穿机制进一步延长保留时间和提高平带电压漂移量。     

Memory characteristics of an MOS capacitor structure with double-layer semiconductor and metal heterogeneous nanocrystals

An MOS (metal oxide semiconductor) capacitor structure with double-layer heterogeneous nanocrystals consisting of semiconductor and metal embedded in a gate oxide for nonvolatile memory applications has been fabricated and characterized. By combining vacuum electron-beam co-evaporated Si nanocrystals and self-assembled Ni nanocrystals in a SiO_2 matrix, an MOS capacitor with double-layer heterogeneous nanocrystals can have larger charge storage capacity and improved retention characteristics compared to one with single-layer nanocrystals. The upper metal nanocrystals as an additional charge trap layer enable the direct tunneling mechanism to enhance the flat voltage shift and prolong the retention time.     

Unraveling the Voltage Failure Mechanism in Metal Sulfide Anodes for Sodium Storage and Improving Their Long Cycle Life by Sulfur-Doped Carbon Protection

Metal sulfides are emerging as a promising anode material for sodium-ion batteries with high reversible capacities and fast reaction kinetics, but achieving long-cycling-life remains a great challenge. Here, taking cobalt sulfide as an example, its electrochemical sodium-ion storage failure phenomenon is first reported, which indicates that the battery cannot reach the cut-off voltage during charging. Detailed analyses demonstrate that such failure may originate from the dissolution and escape of polysulfide intermediates, further reacting with the released copper-ions from the current collector and inducing the occurrence of the shuttle effect. Based on the explored failure mechanism, a sulfur-doped carbon matrix with polar carbon sulfur bonds, which can firmly immobilize the dissolved polysulfides, is deliberately introduced into the Co_1−xS active particles (Co_1−xS/s-C) to improve their cycle stability. Consequently, the cycle life of the Co_1−xS/s-C anode for sodium-ion storage is extended from the original 125 to present 2000 cycles, even at high-rate current densities. Moreover, utilizing the carbon current collector instead of traditional copper can effectively delay the occurrence of the failure phenomenon. The present work promotes better fundamental understanding of the structural evolution of metal sulfide anodes during cycles, and the solution strategy can be extended to apply in other metal sulfides (ZnS, NiS).     

All-Inorganic CsPbBr3 Perovskite Nanocrystals/2D Non-Layered Cadmium Sulfide Selenide for High-Performance Photodetectors by Energy Band Alignment Engineering

Perovskites have attracted intensive attention as promising materials for the application in various optoelectronic devices due to their large light absorption coefficient, high carrier mobility, and long charge carrier diffusion length. However, the performance of the pure perovskite nanocrystals-based device is extremely restricted by the limited charge transport capability due to the existence of a large number of the grain boundary between perovskite nanocrystals. To address these issues, a high-performance photodetector based on all-inorganic CsPbBr₃ perovskite nanocrystals/2D non-layered cadmium sulfide selenide heterostructure has been demonstrated through energy band engineering with designed typed-II heterostructure. The photodetector exhibits an ultra-high light-to-dark current ratio of 1.36 × 10⁵, a high responsivity of 2.89 × 10² A W⁻¹, a large detectivity of 1.28 × 10¹⁴ Jones, and the response/recovery time of 0.53s/0.62 s. The enhancement of the optoelectronic performance of the heterostructure photodetector is mainly attributed to the efficient charge carrier transfer ability between the all-inorganic CsPbBr₃ perovskites and 2D cadmium sulfide selenide resulting from energy band alignment engineering. The charge carriers’ transfer dynamics and the mechanism of the CsPbBr₃ perovskites/2D non-layered nanosheets interfaces have also been studied by state-state PL spectra, fluorescence lifetime imaging microscopy, time-resolved photoluminescence spectroscopy, and Kelvin probe force microscopy measurements.     

Metal Nanocrystal‐Embedded Hollow Mesoporous TiO2 and ZrO2 Microspheres Prepared with Polystyrene Nanospheres as Carriers and Templates

Noble metal nanocrystals with different shapes and compositions are embedded in hollow mesoporous metal oxide microspheres through an ultrasonic aerosol spray. Polystyrene (PS) nanospheres are employed simultaneously as a hard template to create hollow interiors inside the oxide microspheres and as the carrier to bring pregrown metal nanocrystals, including Pd nanocubes, Au nanorods, and Au core/Pd shell nanorods, into the oxide microspheres. Calcination removes the PS template and causes the metal nanocrystals to adsorb on the inner surface of the hollow oxide microspheres. The catalytic performances of the Pd nanocube‐embedded TiO₂ and ZrO₂ microspheres are investigated using the reduction of 4‐nitrophenol as a model reaction. The presence of the mesopores in the oxide microspheres allows the reactant molecules to diffuse into the hollow interiors and subsequently interact with the Pd nanocubes. The embedding of the metal nanocrystals in the hollow oxide microspheres prevents the aggregation of the metal nanocrystals and reduces the loss of the catalyst during recycling. The Pd nanocube‐embedded ZrO₂ microspheres are found to exhibit a much higher catalytic activity, a much larger catalytic reaction rate, and a superior recyclability in comparison with a commercial Pd/C catalyst. This preparation approach could potentially be utilized to incorporate various types of mono‐ and multimetallic nanocrystals with different sizes, shapes, and compositions into hollow mesoporous oxide microspheres. Such a capability can facilitate the studies of the catalytic properties of various combinations of metal nanocrystals and metal oxide supports and therefore guide the design and creation of high‐performance catalysts.     

Colloidal Bi2S3 Nanocrystals: Quantum Size Effects and Midgap States

Among solution‐processed nanocrystals containing environmentally benign elements, bismuth sulfide (Bi₂S₃) is a very promising n‐type semiconductor for solar energy conversion. Despite the prompt success in the fabrication of optoelectronic devices deploying Bi₂S₃ nanocrystals, the limited understanding of electronic properties represents a hurdle for further materials developments. Here, two key materials science issues for light‐energy conversion are addressed: bandgap tunability via the quantum size effect, and photocarrier trapping. Nanocrystals are synthesized with controlled sizes varying from 3 to 30 nm. In this size range, bandgap tunability is found to be very small, a few tens of meV. First principles calculations show that a useful blueshift, in the range of hundreds of meV, is achieved in ultra‐small nanocrystals, below 1.5 nm in size. Similar conclusions are envisaged for the class of pnictide chalcogenides with a ribbon‐like structure [Pn₄Ch₆]_n (Pn = Bi, Sb; Ch = S, Se). Time‐resolved differential transmission spectroscopy demonstrates that only photoexcited holes are quickly captured by intragap states. Photoexcitation dynamics are consistent with the scenario emerging in other metal–chalcogenide nanocrystals: traps are created in metal‐rich nanocrystal surfaces by incomplete passivation by long fatty acid ligands. In large nanocrystals, a lower bound to surface trap density of one trap every sixteen Bi₂S₃ units is found.     

Phase Engineering of Nickel Sulfides to Boost Sodium- and Potassium-Ion Storage Performance

Sulfides are promising anode candidates because of their relatively large theoretical discharge/charge specific capacity and pretty small volume changes, but suffers from sluggish kinetics and structural instability upon cycling. Phase engineering can be designed to overcome the weakness of the electrochemical performance of sulfide anodes. By choosing nickel sulfides (α-NiS, β-NiS, and NiS₂) supported by reduced graphene oxide (rGO) as model systems, it is demonstrated that the nickel sulfides with different crystal structures show different performances in both sodium-ion and potassium-ion batteries. In particular, the α-NiS/rGO display superior stable capacity (≈426 mAh g⁻¹ for 500 cycles at 500 mA g⁻¹) and exceptional rate capability (315 mAh g⁻¹ at 2000 mA g⁻¹). The combined density functional theory calculations and experimental studies reveal that the hexagonal structure is more conducive to ion absorption and conduction, a higher pseudocapacitive contribution, and higher mechanical ability to relieve the stress caused by the volume changes. Correspondingly, the phase engineered nickel sulfide coupled with the conducting rGO network synergistically boosts the electrochemical performance of batteries. This work sheds light on the use of phase engineering as an essential strategy for exploring materials with satisfactory electrochemical performance for sodium-ion and potassium-ion batteries.     

Nanoconfined Expansion Behavior of Hollow MnS@Carbon Anode with Extended Lithiation Cyclic Stability

The construction of hollow nanostructure by compositing with carbonaceous materials is generally considered an effective strategy to mitigate the drastic volume expansion of transition metal sulfides (TMSs) with high theoretical specific capacity in the process of lithium storage. However, designing well-controlled architectures with extended lithiation cyclic stability, and ease the expansion of the electroactive materials into the reserved hollow spaces still needs to be developed. Herein, using MnS as an example, the hollow double-shell carbon-coated TMSs architecture is designed to achieve the controllable operation of shell thickness to regulate interfacial stress. The functional architecture enables the high-capacity MnS to reach reversible capacities and extended lithiation cycling stability at high current densities. In situ transmission electron microscopy, optical observation characterizations and finite elements are used to analyze the nanoconfined expansion behavior of hollow MnS@C anodes. The as-designed hollow structure with a carbon shell thickness ≈12.5 nm can effectively restrict the drastic expansion of MnS nanoshell into inner voids with compressive stress. This study demonstrates a general strategy to design functional carbon coating metal sulfides with tailored interfacial stress.