Nanoscale copper sulfide hollow spheres with phase-engineered composition: covellite (CuS), digenite (Cu1.8S), chalcocite (Cu2S)

Review of Transition Metal Chalcogenides and Halides as Electrode Materials for Thermal Batteries and Secondary Energy Storage Systems

Transition metal chalcogenides and halides (TMCs and TMHs) have been extensively used and reported as electrode materials in diverse primary and secondary batteries. This review summarizes the suitability of TMCs and TMHs as electrode materials focusing on thermal batteries (utilized for defense applications) and energy storage systems like mono- and multivalent rechargeable batteries. The report also identifies the specific physicochemical properties that need to be achieved for the same materials to be employed as cathode materials in thermal batteries and anode materials in monovalent rechargeable systems. For example, thermal stability of the materials plays a crucial role in delivering the performance of the thermal battery system, whereas the electrical conductivity and layered structure of similar materials play a vital role in enhancing the electrochemical performance of the mono- and multivalent rechargeable batteries. It can be summarized that nonlayered CoS2, FeS2, NiS2, and WS2 were found to be ideal as cathode materials for thermal batteries primarily due to their better thermal stability, whereas the layered structures of these materials with a coating of carbon allotrope (CNT, graphene, rGO) were found to be suitable as anode materials for monovalent alkali metal ion rechargeable batteries. On the other hand, vanadium, titanium, molybdenum, tin, and antimony based chalcogenides were found to be suitable as cathode materials for multivalent rechargeable batteries due to the high oxidation state of cathode materials which resists the stronger field produced during the interaction of di- and trivalent ions with the cathode material facilitating higher energy density with minimal structural and volume changes at a high rate of discharge.

Radiation-induced synthesis of copper sulfide nanotubes with improved catalytic and antibacterial activities

In the current paper, copper sulfide nanotubes have been successfully synthesized via the green, simple, and effective gamma-radiolysis method without adding any capping or reducing agents. The structural and morphological characteristics of the as-prepared CuS nanotubes were investigated by X-ray diffraction (XRD), N₂ adsorption-desorption measurements at 77 K, transmission electron microscopy (TEM), and ultraviolet-visible (UV-vis) spectroscopy, which all demonstrated the formation of pure CuS covellite phase with tubular morphology. The synthesized CuS nanotubes possessed not only high activity towards the reduction of both cationic (methylene blue) and anionic (Congo red) dyes in the presence of NaBH₄ but also exhibited excellent reusability. In addition, the pseudo-first-order kinetic model represented the reduction of MB very well, and the value of the normalized rate constant (2.4 × 10^-2 s^-1 mg^-1) was higher than those of other solid catalysts reported in the literature. Ultimately, CuS nanotubes were found to have a broad-spectrum microbicidal action against the common microbiota, such as Gram-positive (exemplified by Bacillus subtilis and Staphylococcus aureus), Gram-negative bacteria (exemplified by Pseudomonas aeruginosa and Escherichia coli), yeast (exemplified by Candida albicans), and plant pathogenic fungi (exemplified by Aspergillus niger).

Controlled Synthesis of CuS and Cu9S5 and Their Application in the Photocatalytic Mineralization of Tetracycline

Pure-phase Cu2−xS (x = 1, 0.2) nanoparticles have been synthesized by the thermal decomposition of copper(II) dithiocarbamate as a single-source precursor in oleylamine as a capping agent. The compositions of the Cu2−xS nanocrystals varied from CuS (covellite) through the mixture of phases (CuS and Cu7.2S4) to Cu9S5 (digenite) by simply varying the temperature of synthesis. The crystallinity and morphology of the copper sulfides were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), which showed pure phases at low (120 °C) and high (220 °C) temperatures and a mixture of phases at intermediate temperatures (150 and 180 °C). Covellite was of a spherical morphology, while digenite was rod shaped. The optical properties of these nanocrystals were characterized by UV−vis–NIR and photoluminescence spectroscopies. Both samples had very similar absorption spectra but distinguishable fluorescence properties and exhibited a blue shift in their band gap energies compared to bulk Cu2−xS. The pure phases were used as catalysts for the photocatalytic degradation of tetracycline (TC) under visible-light irradiation. The results demonstrated that the photocatalytic activity of the digenite phase exhibited higher catalytic degradation of 98.5% compared to the covellite phase, which showed 88% degradation within the 120 min reaction time using 80 mg of the catalysts. The higher degradation efficiency achieved with the digenite phase was attributed to its higher absorption of the visible light compared to covellite.

An atom efficient, single-source precursor route to plasmonic CuS nanocrystals

The synthesis of colloidal semiconductor nanocrystals (NCs) from single-source precursors offers simplified manufacturing processes at the cost of reduced atom efficiency. Self-capping routes have the potential to maximise this efficiency although investigation has so far been limited to organic solvents. Here we present the synthesis of copper sulfide NCs via the decomposition of a copper dithiocarbamate complex in water. Nanocrystalline covellite particles were prepared without the need for additional capping ligand and exhibited a hollow nanosphere morphology. Mass spectrometry of the water-stable NCs indicated the presence of a number of surface ligands, including a small amine fragment of the single-source precursor (SSP) complex. A broad plasmon resonance in the near-infrared (NIR) at 990 nm was also observed and the photothermal effect of this demonstrated. Cytotoxicity experiments indicated cell viability remained above 95% for NC concentrations up to 1 mg mL^-1, indicating high biocompatibility.

Copper sulfide nanoplates as nanosensors for fast, sensitive and selective detection of DNA

The present communication reports on a novel high-sensitivity DNA sensor based on cooper sulfide nanoplates (CuS NPs). The CuS NPs are successfully synthesized through a mild one-step hydrothermal method. As an efficient nanosensor for the fluorescent detection of DNA, the CuS NPs possess high sensitivity and selectivity with a detection limit of 25pM.

Diversified copper sulfide (Cu2-xS) micro-/nanostructures: a comprehensive review on synthesis, modifications and applications

As a significant metal chalcogenide, copper sulfide (Cu_2-xS, 0 < x < 1), with a unique semiconducting and nontoxic nature, has received significant attention over the past few decades. Extensive investigations have been employed to the various Cu_2-xS micro-/nanostructures owing to their excellent optoelectronic behavior, potential thermoelectric properties, and promising biomedical applications. As a result, micro-/nanostructured Cu_2-xS with well-controlled morphologies, sizes, crystalline phases, and compositions have been rationally synthesized and applied in the fields of photocatalysis, energy conversion, in vitro biosensing, and in vivo imaging and therapy. However, a comprehensive review on diversified Cu_2-xS micro-/nanostructures is still lacking; therefore, there is an imperative need to thoroughly highlight the new advances made in function-directed Cu_2-xS-based nanocomposites. In this review, we have summarized the important progress made in the diversified Cu_2-xS micro-/nanostructures, including that in the synthetic strategies for the preparation of 0D, 1D, 2D, and 3D micro-/nanostructures (including polyhedral, hierarchical, hollow architectures, and superlattices) and in the development of modified Cu_2-xS-based composites for enhanced performance, as well as their various applications. Furthermore, the present issues and promising research directions are briefly discussed.

A simple approach to the synthesis of Cu1.8S dendrites with thiamine hydrochloride as a sulfur source and structure-directing agent

A facile, green and environmental-friendly method for preparing Cu1.8S dendrites was developed. Copper nitrate and thiamine hydrochloride were selected as the starting materials in the water phase under hydrothermal conditions. No addition of a surfactant or a complex reagent was required for the synthesis of the Cu1.8S dendrite structures. Thiamine hydrochloride was employed as a sulfur source and structure-directing agent. The growth mechanism of Cu1.8S is tentatively discussed based on the experimental and computational results.

Nanostructured copper sulfides: synthesis, properties and applications

Copper sulfides are the most extensively studied materials due to their non-toxicity, semiconducting nature and tunable properties. In view of this, present review article discusses various synthetic strategies for the fabrication of nanostructured copper sulfides of different morphologies and properties comprehensively followed by their applications in various fields.

Enhanced photovoltaic performance and time varied controllable growth of a CuS nanoplatelet structured thin film and its application as an efficient counter electrode for quantum dot-sensitized solar cells via a cost-effective chemical bath deposition

CuS counter electrodes on FTO substrates are synthesised.

Controllable synthesis of various kinds of copper sulfides (CuS, Cu7S4, Cu9S5) for high-performance supercapacitors

The whole shape evolutionary process of snowflake-like Cu₇S₄ microstructures could be controlled by adjusting the concentration of ethylenediamine.

Controlled synthesis of CuS caved superstructures and their application to the catalysis of organic dye degradation in the absence of light

CuS caved superstructures with a variety of sizes and regular shapes were synthesized by an innovative one-pot method, which showed excellent catalytic properties evaluated by degradation of methylene blue (MB) without light.

Nanostructured metal sulfides for energy storage

Advanced electrodes with a high energy density at high power are urgently needed for high-performance energy storage devices, including lithium-ion batteries (LIBs) and supercapacitors (SCs), to fulfil the requirements of future electrochemical power sources for applications such as in hybrid electric/plug-in-hybrid (HEV/PHEV) vehicles. Metal sulfides with unique physical and chemical properties, as well as high specific capacity/capacitance, which are typically multiple times higher than that of the carbon/graphite-based materials, are currently studied as promising electrode materials. However, the implementation of these sulfide electrodes in practical applications is hindered by their inferior rate performance and cycling stability. Nanostructures offering the advantages of high surface-to-volume ratios, favourable transport properties, and high freedom for the volume change upon ion insertion/extraction and other reactions, present an opportunity to build next-generation LIBs and SCs. Thus, the development of novel concepts in material research to achieve new nanostructures paves the way for improved electrochemical performance. Herein, we summarize recent advances in nanostructured metal sulfides, such as iron sulfides, copper sulfides, cobalt sulfides, nickel sulfides, manganese sulfides, molybdenum sulfides, tin sulfides, with zero-, one-, two-, and three-dimensional morphologies for LIB and SC applications. In addition, the recently emerged concept of incorporating conductive matrices, especially graphene, with metal sulfide nanomaterials will also be highlighted. Finally, some remarks are made on the challenges and perspectives for the future development of metal sulfide-based LIB and SC devices.

Controlled synthesis and catalytic activity of copper sulfide nanostructured assemblies with different morphologies

A simple, template-free and mild solution chemistry route was employed to synthesize diverse copper sulfide (CuS) nanostructured assemblies at 70 °C by varying the solvent (water or ethylene glycol, or their ratios (3:1, 1:1 and 1:3)). The CuS structures in the shape of spheres and nanotubes were found to be assemblies of either nanoplates or nanoparticles. The nanotube formation was elaborately studied by varying the synthesis parameters such as temperature, reaction duration, precursor's ratio, and counterions. Counterions such as NO3(-) and SO4(2-) were found to be suitable for nanotube formation whereas in the presence of Cl(-) and OAc(-) ions, CuS flake-like and nanoparticle assemblies are obtained, respectively. The optical bandgaps for the CuS with different morphologies were measured to be in the range of 1.88-2.16 eV. The bandgap of CuS in the visible region of electromagnetic radiation prompted it to be used as photocatalyst in the past under natural light. However, we demonstrate here the similar catalytic performance of as-synthesized CuS nanostructures for the degradation of methylene blue in the dark, suggesting that light does not play a role in its catalytic behavior.

Growth evolution and phase transition from chalcocite to digenite in nanocrystalline copper sulfide: Morphological, optical and electrical properties

Copper sulfide is a promising p-type inorganic semiconductor for optoelectronic devices such as solar cells, due its small band gap energy and its electrical properties. In this work nanocrystalline copper sulfide (Cu x S), with two stoichiometric ratios (x = 2, 1.8) was obtained by one-pot synthesis at 220, 230, 240 and 260 °C in an organic solvent and amorphous Cu x S was obtained in aqueous solution. Nanoparticle-like nucleation centers are formed at lower temperatures (220 °C), mixtures of morphologies (nanorods, nanodisks and nanoprisms) are seen at 230 and 240 °C, in which the nanodisks are predominant, while big hexagonal/prismatic crystals are obtained at 260 °C according to TEM results. A mixture of chalcocite and digenite phases was found at 230 and 240 °C, while a clear transition to a pure digenite phase was seen at 260 °C. The evolution of morphology and transition of phases is consistent to the electrical, optical, and morphological properties of the copper sulfide. In fact, digenite Cu1.8S is less resistive (346 Ω/sq) and has a lower energy band gap (1.6 eV) than chalcocite Cu2S (5.72 × 10(5) Ω/sq, 1.87 eV). Low resistivity was also obtained in Cu x S synthesized in aqueous solution, despite its amorphous structure. All Cu x S products could be promising for optoelectronic applications.

Fabrication of "strong" columnar Cu2-xSe superstructures assisted by inorganic ligands

In this report, Cu(2-x)Se nanoplates with columnar superstructures have been synthesized via a facile, "green", phosphine-free, low-cost colloidal method. An inorganic tin(iv) selenium complex (Sn(2)Se(6))(4-) was attached on the surfaces of Cu(2-x)Se nanoplates directly during the synthesis of Cu(2-x)Se nanoplates. With the assistance of (Sn(2)Se(6))(4-) complexes, Cu(2-x)Se nanoplates showed "strong" self-assembly behavior and the stability of Cu(2-x)Se nanoplate superstructures was increased. Such columnar superstructures were still kept even if most of the coordinating organic ligands were removed by washing. The mechanism of the formation of "strong" columnar Cu(2-x)Se superstructures had been studied. We found the "strong" self-assemblies of Cu(2-x)Se nanoplates were formed only with the coexistence of oleylamine (OAM) and Sn-X in the synthesis process. The inorganic ligand not only played a key role in the construction of the "strong" columnar Cu(2-x)Se superstructure but also greatly improved their superior electrical property.