Metal Chalcogenide Nanomaterials Research Articles

Synthesis and Electrocatalytic Applications of Noble Metal Chalcogenides Nanomaterials

AbstractIn this review, we first focus on summarizing recent advances in effective and facile strategies for the ration synthesis of noble metal chalcogenide nanomaterials (NMCNs), and then, we systematically introduce their applications in catalyzing typical electrochemical reactions. Finally, we make some perspectives on the challenges for using NMCNs in electrocatalysis with respect to further enhancement of their electrocatalytic performance.

One‐pot hydrothermal synthesis of Cu2Te/NiTe nanocomposite materials: A structural, morphological, and optical study

AbstractDue to various structural and optical properties, metal chalcogenide nanomaterials are favorable candidates for different optoelectronic applications. In the current report, Cu2Te/NiTe nanocomposites were synthesized via the facile hydrothermal method. With the variation of concentration of Cu and Ni, various materials had been prepared along with pure Cu2Te and NiTe. The observed several vibrational modes in the material through the Raman spectroscopy are well agreed with the appearing phases. The morphological study confirmed the nanostructures are combination of nanoparticles with sheets. The size of nanoparticles varied in the range of 66–34 nm. The absorbance spectra of the nanocomposite exhibit a blueshift and support the enhancement in the optical bandgap. The value of bandgap energy of the composite samples has been noted in the range of 1.8–2.2 eV. This bandgap range enables the material for various optoelectronic applications such as solar cell and other photovoltaic devices. Thermal analysis of the material demonstrates the presences of several endothermic and exothermic peaks. Thus, several studies on the material prevail its various applicability as optoelectronics as well as other thermal application.

Solution-phase synthesis of group 3-5 transition metal chalcogenide inorganic nanomaterials.

The versatility of early transition metal chalcogenide nanomaterials, including chalcogenide perovskites, has attracted enormous attention for a variety of applications, such as photovoltaics, photocatalysis, and optoelectronic devices. These nanomaterials exhibit unique electronic and optical properties, allowing for a broad range of applications, depending on their chemical composition and crystal structure. However, solution-phase synthesis of early transition metal chalcogenide nanocrystals is challenging due, in part, to their high crystallization energy and oxophilicity. In this feature article, we explore various synthetic routes reported for inorganic ternary and binary sulfide and selenide nanomaterials that include transition metals from groups 3, 4, and 5. By systematically comparing different synthetic approaches, we identify trends and insights into the chemistry of these chalcogenide nanomaterials.

Two-dimensional transition metal chalcogenide nanomaterials for cancer diagnosis and treatment

For more than a decade, the exfoliation of graphene and other layered materials has led to a tremendous amount of research in two-dimensional (2D) materials, among which 2D transition metal chalcogenides (TMCs) nanomaterials have attracted much attention in a wide range of applications including photoelectric devices, lithium-ion batteries, catalysis, and energy conversion and storage owing to their unique photoelectric physical properties. With such large specific surface area, strong near-infrared (NIR) absorption and abundant chemical element composition, 2D TMCs nanomaterials have become good candidates in biomedical imaging and cancer treatment. This review systematically summarizes recent progress on 2D TMCs nanomaterials, which includes their synthesis methods and applications in cancer treatment. At the end of this review, we also highlight the future prospects and challenges of 2D TMCs nanomaterials. It is expected that this work can provide the readers with a detailed overview of the synthesis of 2D TMCs and inspire more novel functional biomaterials based on 2D TMCs for cancer treatment in the future. 2D transition metal chalcogenides (TMCs) have received growing attention in biomedical imaging and cancer treatment because of their large specific surface area, strong near-infrared (NIR) absorption and abundant chemical element composition.

Controllable synthesis of surfactants (PEG and SDS) assisted Copper Selenide Nanoparticles by hydrothermal method for photocatalytic activity

Semiconductor metal chalcogenide nanomaterials are excellent materials which possess interesting properties like existing in different structures under different conditions of synthesis, layered growth nature, low tunable bandgap and can be grown in ambient environmental conditions, etc. Copper Selenide (Cu2Se) is an important p-type semiconducting material, with band gaps 1.2–2.3 eV. Copper Selenide has a wide range of applications in various areas of research such as optical filters, super ionic conductors, window materials, thermal electric conductors and photo electric devices. The experimental synthesis of copper selenide was carried out by the hydrothermal route. The size of nanomaterials can be controlled when it is capped with different types of surfactants (cationic, anionic, nonionic or Zwitter ionic). Two types of surfactants, say sodium dodecyl sulphate (SDS), an anionic surfactant and polyethylene glycol (PEG), a non-ionic surfactant were chosen to study their influence on the particle size. The various characterization techniques namely XRD, UV, SEM, TEM, Dielectric studies and photocatalytic activity were adopted to analysis the samples.

Ultra-mild synthesis of nanometric metal chalcogenides using organyl chalcogenide precursors

Bis(trialkylsilyl) monochalcogenides and diorganyl dichalcogenides, (R3Si)2E and R2E2 (E = S, Se or Te and R = alkyl, aryl or allyl group), have emerged in the past decade as excellent reagents for the synthesis of metal chalcogenide nanoparticles (NPs) and clusters owing to their ability to transfer the chalcogenide anion (E2-) under ultra-mild conditions and versatility in reacting even with non-conventional metal reagents or being employed in a variety of synthetic methods. In comparison, the related non-silylated diorganyl monochalcogenides R2E have received attention only recently for the solution phase synthesis of metal chalcogenide NPs. In spite of sharing many similarities, these three families of organyl chalcogenides are different in their coordination ability and decomposition behavior, and therefore in reactivities towards metal reagents. This feature article provides a concise overview on the use of these three families as synthons for the ultralow-temperature synthesis of metal chalcogenide nanomaterials, deliberating their different decomposition mechanisms and critically assessing their advantages for certain applications. More specifically, it discusses their usefulness in (i) affording molecular precursors with different kinetic and thermal stabilities, (ii) isolating reactive intermediates for comprehending the mechanism of molecule-to-nanoparticle transformation and, therefore, achieving fine control over the synthesis, (iii) stabilizing isolable metastable or difficult-to-achieve phases, and (iv) yielding complex ternary nanoparticles with controlled stoichiometry or composites with sensitive materials without modifying the characteristics of the latter. Besides providing a perspective on the low-temperature synthesis of nanomaterials, this overview is expected to assist further progress, particularly in the field of R2E, leading to interesting materials including metastable ones for new applications.

Soft chemistry of metastable metal chalcogenide nanomaterials.

The metastable nature of metal chalcogenide nanomaterials (MCNs) provides us with fresh perspectives and plentiful grounds in the search of new strategies for physicochemical tuning. In the past decade, numerous efforts have been devoted to synthesizing and modifying diverse emerging MCNs based on their "soft chemistry", that is, gently regulating the composition, structure, phase, and interface while not entirely disrupting the original features. This tutorial review focuses on design principles based on the metastability of MCNs, such as ion mobility and vacancy, thermal and structural instability, chemical reactivity, and phase transition, together with corresponding soft chemical approaches, including ion-exchange, catalytic growth, segregation or coupling, template grafting or transformation, and crystal-phase engineering, and summarizes recent advances in their preparation and modification. Finally, prospects for the future development of soft chemistry-directed synthetic guidelines and metastable metal chalcogenide-derived nanomaterials are proposed and highlighted.

Colloidal synthesis of metal chalcogenide nanomaterials from metal-organic precursors and capping ligand effect on electrocatalytic performance: progress, challenges and future perspectives.

Renewable and sustainable functional nanomaterials, which can be employed in alternative green energy sources, are highly desirable. Transition metal chalcogenides are potential catalysts for processes resulting in energy generation and storage. In order to optimize their catalytic performance, high phase purity and precise control over shape and size are indispensable. Metal-organic precursors with pre-formed bonds between the metal and the chalcogenide atoms are advantageous in synthesizing phase pure transition metal chalcogenides with controlled shape and sizes. This can be achieved by the decomposition of metal-organic precursors in the presence of suitable surfactants/capping agents. However, the recent studies on electrocatalysis at the nanoscale level reveal that the capping agents attached to their surface have a detrimental effect on their efficiency. The removal of surfactants from active sites to obtain bare surface nanoparticles is necessary to enhance catalytic activity. Herein, we have discussed the properties of different metal-organic precursors and the role of surfactants in the colloidal synthesis of metal chalcogenide nanomaterials. Moreover, the effect of surfactants on their electrocatalytic performance, the commonly used strategies for removing surfactants from the surface of nanomaterials and the future perspectives are reviewed.

Magic-Sized Stoichiometric II-VI Nanoclusters.

Metal chalcogenide nanomaterials have gained widespread interest in the past two decades for their potential optoelectronic, energy, and catalytic applications. The colloidal growth of various forms of these materials, such as nanowires, platelets, and lamellar assemblies, proceeds through certain thermodynamically stable, ultrasmall (<2nm) intermediates called magic-sized nanoclusters (MSCs). Due to quantum confinement and its resultant intriguing properties, isolation or direct synthesis of MSCs and their structure characterization, which is very much challenging, are current topics of fundamental and applied scientific research. By comprehensive understanding of the structure-activity relationships in MSCs, the nucleation and growth processes can be manipulated, resulting in the synthesis of novel metal chalcogenide materials for various applications. This review focuses on recent advances in the chemical synthesis, characterization, and theoretical calculations of CdSe and its related II-VI nanoclusters. It highlights the studies of photophysical and magneto-optical properties as well as heteroatom doping of MSCs followed by their chemical transformation to high-dimensional nanostructures. At the end of the review, future directions and possible ways to overcome the challenges in the research of semiconductor MSCs are also presented.

Electrochemical atomic layer deposition of cadmium telluride for Pt decoration: Application as novel photoelectrocatalyst for hydrogen evolution reaction

Metal-chalcogenide nanomaterials, as compared to their wide bandgap counterparts, are particularly attractive photoelectrocatalytic materials for the conversion of solar energy into chemical energy under visible-light irradiation. In this study, the thin layer of CdTe was deposited on the surface of Au/ITO electrode using electrochemical atomic layer deposition. Deposition process was performed through the alternate under potential deposition of the Te and Cd elements with a monolayer at a time, respectively. The images of scaning electron microscopy (SEM) indicated that nanoparticles of CdTe well dispersed on Au/ITO with an average particle size about 15 nm. The results of energy dispersive analysis by X-rays (EDAX) confirmed the off-stoichiometric CdTe layer, which lead to Cd-rich CdTe because of tellurium vacancies in the deposition potential. The resulting Cd-rich CdTe/Au/ITO electrode was used for preparation of Pt/CdTe/Au/ITO by redox replacement reaction between Pt2+ and Cd excess in CdTe layer to form 1.76 wt% of Pt element which uniformly distributed on the surface of CdTe/Au/ITO. Chronoamperometric tests in sodium sulfide solution exhibited that the Cd-rich CdTe layer had n-type semiconductivity whereas the Pt/CdTe layer showed p-type semiconductivity. The Pt/CdTe/Au/ITO electrode showed higher photoelectrocatalytic activity for the HER as compared to a commercial Pt/C on Au/ITO. The onset potential for HER is almost similar and the overpotential at −10 mA cm−2 is 160 mV more positive on Pt/CdTe/Au/ITO under light illumination with respect to Pt/C/Au/ITO. The long-term stability tests under illumination in acidic solution revealed that Cd-rich CdTe and Pt/CdTe layeres have extremely high stablity for HER compared to Pt/C. The higher photocatalytic activity on Pt/CdTe/Au/ITO electrode for HER is attributed predominantly to the synergistic effect of Pt, which not only serves as co-catalysts for promoting electron transfer to the electrocatalyst-electrolyte interface, but also accelerates the HER.

MicroJet Reactor Technology: An Automated, Continuous Approach for Nanoparticle Syntheses

AbstractA new design of a confined impinging jet microreactor has been applied for continuous‐flow syntheses of metal chalcogenide nanomaterials. The microjet reactor is an automated, flexible, scalable, and thus industrially viable technology allowing a strict control over process parameters for the design of materials with tunable properties. Due to the short mixing times in the µs to ms range, crystallite nucleation and crystal growth are well separated and enable concentration‐limited particle growth and thus nanoparticle synthesis. The first approaches on the microjet reactor setup presented here were focused on the synthesis of nanocrystalline Ta‐doped tin dioxides and cadmium sulfide nanoparticles. The nanomaterials were characterized by a number of methods like powder X‐ray diffraction and conductivity measurements.

Near-Infrared Optical Modulation for Ultrashort Pulse Generation Employing Indium Monosulfide (InS) Two-Dimensional Semiconductor Nanocrystals.

In recent years, metal chalcogenide nanomaterials have received much attention in the field of ultrafast lasers due to their unique band-gap characteristic and excellent optical properties. In this work, two-dimensional (2D) indium monosulfide (InS) nanosheets were synthesized through a modified liquid-phase exfoliation method. In addition, a film-type InS-polyvinyl alcohol (PVA) saturable absorber (SA) was prepared as an optical modulator to generate ultrashort pulses. The nonlinear properties of the InS-PVA SA were systematically investigated. The modulation depth and saturation intensity of the InS-SA were 5.7% and 6.79 MW/cm2, respectively. By employing this InS-PVA SA, a stable, passively mode-locked Yb-doped fiber laser was demonstrated. At the fundamental frequency, the laser operated at 1.02 MHz, with a pulse width of 486.7 ps, and the maximum output power was 1.91 mW. By adjusting the polarization states in the cavity, harmonic mode-locked phenomena were also observed. To our knowledge, this is the first time an ultrashort pulse output based on InS has been achieved. The experimental findings indicate that InS is a viable candidate in the field of ultrafast lasers due to its excellent saturable absorption characteristics, which thereby promotes the ultrafast optical applications of InX (X = S, Se, and Te) and expands the category of new SAs.

Synthesis of MnS from Single- and Multi-Source Precursors for Photocatalytic and Battery Applications

Nanomaterials have been shown to possess exclusive properties in heterogeneous catalysis as evidenced by studies dedicated to the synthesis of transition-metal-containing nanomaterials. However, the series of nanomaterials which have been synthesized are mostly oxides. A ligand, 1-(2-chloro-4-nitrophenyl)-3,3-chlorobenzoyl (Tu), has been created through which MnS nanoparticles (NPs) and nanosheets (NSs) have been successfully synthesized, initially from a single-source precursor (SS) and then from multi-source precursors, respectively. The main objective of this article was to identify the differences in the morphologies of the materials synthesized from the two different sources, with photodegradation and battery applications performed just with MnS NPs (synthesized by the SS method). A preliminary study has been carried out on the photocatalytic properties and battery applications of the recently synthesized MnS employing the SS method. MnS NPs demonstrated higher activity than their bulk sheet for the photocatalytic degradation of four different dyes, methyl violet, methylene green, methylene blue, and rhodamine B, under visible-light irradiation. More significantly, the preparation method in the present work might be applied to other metal chalcogenide nanomaterials for various new applications. More notably, battery applications have been evaluated for MnS NPs (synthesized by the SS method) by testing their electrochemical discharge/charge at voltage limits of − 0.2 to 3.2 V versus Li/Li+.

Facilitated Lithium Storage in Hierarchical Microsphere of Cu2S‐MoS2 Ultrathin Nanosheets

AbstractConsidering the high energy density Lithium ion batteries have become one of the best option for next‐generation energy‐storage technologies. Transition metal chalcogenide nanomaterials are promising electrodes for Lithium‐ion batteries. Molybdenum based layered chalcogenide materials wisely studied for rechargeable Li‐ion batteries, due to its two‐dimensional (2D) layered structure and better specific capacity. The three‐dimensional (3D) synthesis of microsphere by ultrathin nanosheets is necessary for practical applications. Herein, the fabrication of a unique hierarchical 2D layered Cu2S‐MoS2 nanostructure was (ultrathin nanosheets) demonstrated via in situ assembling of two‐dimensional (2D) growths in facile solvothermal technique. The structural study reveals the existence of Cubic Cu2S and Rhombohedral MoS2 phase. Morphological study by FESEM and TEM shows unique ultrathin nanosheets of ∼10 nm thickness self‐assembled in the form of layered microsphere. In Li‐ion storage testing, Cu2S‐MoS2 electrode exhibited good specific discharge capacity of 651 mAhg−1at 50 mAg−1 applied current and maintained 320 mAhg−1 after 100 cycles. The facilitated advanced electrochemical performance attributed to layered ultrathin Cu2S‐MoS2 composite nanosheets.

Adaptable surfactant-mediated method for the preparation of anisotropic metal chalcogenide nanomaterials

The hot injection synthesis of nanomaterials is a highly diverse and fundamental field of chemical research, which has shown much success in the bottom up approach to nanomaterial design. Here we report a synthetic strategy for the production of anisotropic metal chalcogenide nanomaterials of different compositions and shapes, using an optimised hot injection approach. Its unique advantage compared to other hot injection routes is that it employs one chemical to act as many agents: high boiling point, viscous solvent, reducing agent, and surface coordinating ligand. It has been employed to produce a range of nanomaterials, such as CuS, Bi2S3, Cu2-xSe, FeSe2, and Bi4Se3, among others, with various structures including nanoplates and nanosheets. Overall, this article will highlight the excellent versatility of the method, which can be tuned to produce many different materials and shapes. In addition, due to the nature of the synthesis, 2D nanomaterial products are produced as monolayers without the need for exfoliation; a significant achievement towards future development of these materials.

Synthesis and Characterization of Cadmium Chalcogenide Nanomaterial (CdE; E=Se/Te) from Novel Single Source Molecular Precursor

Background: Metal chalcogenide nanomaterials represent an important group of efficient materials, in which the subtle variations in shape, size and phase of nano-powders resulted in physical properties (e.g., electronic and optical) differing from their bulk counterparts, which makes them useful materials for various technological devices. Objective: Synthesis and growth of chalcogenide nano powders from novel single source molecular precursors (i.e., Cd(II) bis-(aminopropane) selenide, Cd(II) bis-(aminoethane) telluride) for the production of cadmium chalcogenide (CdE, E= Se/Te) at nano scale. Method: Single source molecular precursor inserted in quinoline, acting as a coordinating solvent at suitable temperature, yielded vacuum dried powders of CdSe and CdTe nanomaterials. Results: The average particle size was estimated as CdSe ≈ 3 nm, and CdTe ≈ 29 nm from powder X-ray diffraction pattern of synthesized nanoparticles. The produced nanomaterials possess optical properties and calculated energy band gap of nanoparticles as CdTe = 5.2 eV and CdSe = 4.0 eV from UV-Visible spectra. Conclusion: The economical, harmless single source molecular method may be a striking technique to fabricate metal chalcogenide nanoparticles.

Ultrathin Two-Dimensional Multinary Layered Metal Chalcogenide Nanomaterials.

Ultrathin two-dimensional (2D) layered transition metal dichalcogenides (TMDs), such as MoS2 , WS2 , TiS2 , TaS2 , ReS2 , MoSe2 and WSe2 , have attracted considerable attention over the past six years owing to their unique properties and great potential in a wide range of applications. Aiming to achieve tunable properties and optimal application performances, great effort is devoted to the exploration of 2D multinary layered metal chalcogenide nanomaterials, which include ternary metal chalcogenides with well-defined crystal structures, alloyed TMDs, heteroatom-doped TMDs and 2D metal chalcogenide heteronanostructures. These novel 2D multinary layered metal chalcogenide nanomaterials exhibit some unique properties compared to 2D binary TMD counterparts, thus holding great promise in various potential applications including electronics/optoelectronics, catalysis, sensors, biomedicine, and energy storage and conversion with enhanced performances. This article focuses on the state-of-art progress on the preparation, characterization and applications of ultrathin 2D multinary layered metal chalcogenide nanomaterials.

Solution synthesis of conveyor-like MnSe nanostructured architectures with an unusual core/shell magnetic structure

We report for the first time one-dimensional (1D) wurtzite (WZ) MnSe nanoconveyors with a single-crystalline configuration fabricated by a solution-processed colloidal method. High-resolution transmission electron microscopy (HRTEM) measurements show that the stem of MnSe nanoconveyors grows along the [100] direction, while the teeth grow along the [0001] direction. We find that the initial WZ nanobelts with the [100] growth direction are crucial to the formation of nanoconveyors, whereas the teeth are a result of a self-catalyzed growth process induced by the Mn-terminated (0001) surface. The magnetic measurements suggest that 1D WZ MnSe nanoconveyors consist of an antiferromagnetic core and a ferromagnetic shell below the blocking temperature. Furthermore, the hysteresis measurements indicate that these nanoconveyors have 300 Oe coercive fields, which is attributed to the high surface-to-volume ratio of the nanoconveyors. This facile solution-based strategy can be anticipated to synthesize WZ metal chalcogenide nanomaterials with 1D hierarchical structures, for potential applications from spintronics to photocatalysis.

Improved cycling stability of the capping agent-free nanocrystalline FeS2 cathode via an upper cut-off voltage control

Transition metal chalcogenides such as FeS2 are promising electrode materials for energy storage. However, poor rate performance and low cycling stability hinder the practical application of FeS2 cathode in secondary batteries. In this study, highly pure pyrite FeS2 nanocrystals (NCs) with octahedral shape and 200–300 nm size have been synthesized via a facile and environmentally benign approach based on a surfactant-free aqueous reaction. Combined with a compatible ether electrolyte, the prepared FeS2 NCs, despite their dimension far beyond the quantum confined regime, could achieve high utilization and reversibility as a cathode active material due to the well-defined crystal structure and the uncapped rough surfaces. Furthermore, we find that the last charging voltage step of FeS2 only contributes a minor capacity but caused severe capacity fading due to the formation of soluble polysulfides. By suppressing this step through setting a proper upper cut-off voltage, the cycle life of the Li/FeS2 cell is dramatically improved. The Li/FeS2 cell running over a voltage window of 1.0–2.4 V at 1C delivers an initial capacity of 486.1 mA h g−1, slightly lower than that running over 1.0–3.0 V (561.1 mA h g−1), but outperforms the latter substantially after 500 cycles (367 mA h g−1 vs 315 mA h g−1), corresponding to a capacity decay rate as low as 0.048% per cycle. Our results provide a meaningful approach for the development of not only the advanced FeS2 material for long-life rechargeable batteries, but also other transition metal chalcogenide nanomaterials for a variety of potential applications.

Solution-based synthesis of anisotropic metal chalcogenide nanocrystals and their applications

This article reviews recent advances in solution-phase synthesis of anisotropic metal chalcogenide nanomaterials (1-D &amp; 2-D) and their practical applications with some challenges in the solution-based synthesis.