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Quantum chemical modeling of CO oxidation on the Cu12S6(PH3)8 and Cu12S6 clusters was performed in order to establish the general tendencies in the process on metal nanoclusters stabilized by ligands and to find out if the presence of a phosphine ligand is needed in the active site. The Langmuir–Hinshelwood mechanism was studied, which involves sequential oxidation of two CO molecules with oxygen. The calculated activation energies on Cu12S6(PH3)8 are lower than on Cu12S6 for all oxidation stages; therefore, the PH3 ligands have a positive effect on the catalytic properties of the copper sulfide cluster in the CO oxidation. A linear correlation was found between the energy of CO adsorption on various copper sulfide clusters and the activation energy of the oxidation stage: the lowest activation energy is observed for the cluster with a CO adsorption energy of 36 kJ/mol. [ABSTRACT FROM AUTHOR]

In this study, a high-efficiency reduced graphene oxide and Cu 2 S composite counter electrode for quantum dot-sensitized solar cells is investigated via various hydrothermal times (12, 24, and 36 h). Besides, for comparison, Cu 2 S CE was fabricated by hydrothermal and chemical bath deposition methods. The morphology of the nanocomposites was studied using a field emission scanning electron microscope and high-resolution transmission electron microscopy. It confirms the formation of nanoflower-like Cu 2 S intermixed with rGO sheets. The presence of Cu 2 S and rGO in rGO/Cu 2 S composites was identified by X-ray diffraction, selected area electron diffraction, Fourier-transform infrared spectroscopy, and Raman spectra. The chemical composition and purity of rGO/Cu 2 S were examined by X-ray photoelectron spectroscopy. The electrochemical property of the as-fabricated counter electrode was studied by cyclic voltammetry analysis using the sulfide/polysulfide-based electrolyte. The optimum hydrothermal time was 24 h. The power conversion efficiency of 5.187 % for rGO/Cu 2 S 24-h counter electrode is higher than that of reduced graphene oxide (4.013 %), synthesized chemical bath deposition (3.466 %), and hydrothermal Cu 2 S (3.112 %) counter electrodes, respectively. The main reason is the Cu 2 S nanoflower morphology and the conductive reduced graphene oxide network, which provide more catalytically active sites and a rapid electron transport pathway. Overall, the ease of synthesis, low cost, time efficiency, and excellent electrocatalytic characteristics of the rGO/Cu 2 S composites demonstrated a promising counter electrode. [ABSTRACT FROM AUTHOR]

In this work, flexible Cu2−xS films on nylon membranes are prepared by combining a simple hydrothermal synthesis and vacuum filtration followed by hot pressing. The films consist of Cu2S and Cu1.96S two phases with grain sizes from nano to submicron. Doping Se on the S site not only increases the Cu1.96S content in the Cu2−xS to increase carrier concentration but also modifies electronic structure, thereby greatly improves the electrical properties of the Cu2−xS. Specifically, an optimal composite film with a nominal composition of Cu2−xS0.98Se0.02 exhibits a high power factor of ~150.1 μW m−1 K−2 at 300 K, which increases by ~138% compared to that of the pristine Cu2−xS film. Meanwhile, the composite film shows outstanding flexibility (~97.2% of the original electrical conductivity is maintained after 1500 bending cycles with a bending radius of 4 mm). A four-leg flexible thermoelectric (TE) generator assembled with the optimal film generates a maximum power of 329.6 nW (corresponding power density of 1.70 W m−2) at a temperature difference of 31.1 K. This work provides a simple route to the preparation of high TE performance Cu2−xS-based films. [ABSTRACT FROM AUTHOR]

Undoped and Chromium (Cr) doped (2, 4%) copper sulfide (Cu2S) nanostructured thin films were created by spray pyrolysis. The films were polycrystalline and combined cubic and monoclinic structures, according to the results of the XRD investigation. Surface roughness values for the doped and undoped thin films are 8.71, 7.79, and 3.24 nm, respectively. SEM images display Cu2S nanostructures with fine crystallites and traces of nanorod. Chromium doping increases particle size and induces nanorod growth, enhancing surface porosity. The optical examination shows that Cr-doped Cu2S thin films exhibit effective absorption (> 104 orders) in the visible range. From the change in absorption coefficient, it can be observed that there is a valley around 2.6 eV. By doping Cr (up to 2%) in Cu2S films, it is possible to control the band gap between 2.62 eV and 2.73 eV. The refractive index of undoped Cu2S films decreases with increasing Cr-doping concentration. Gas sensing of Chromium-doped and undoped Cu2S nanostructures involves dynamic resistance change at 100°C. Undoped Cu2S displays low resistance, exhibiting p-type semiconductor behavior. Notably, 4% Cr-doped Cu2S shows high resistance, and the introduction of NO2 decreases resistance. Decreased sensitivity with rising Cr doping in Cu2S: 2% Cr and Cu2S: 4% Cr. Responsiveness declined across different NO2 concentrations (200 ppm, 300 ppm, and 400 ppm). [ABSTRACT FROM AUTHOR]

The threat of ozone in indoor spaces and other enclosed environments is receiving increasing attention. Among numerous ozone catalytic decomposition technologies, copper catalytic material has a superior performance and relatively low cost, making it one of the ideal catalyst materials. This review presents the recent Cu catalyst studies on ozone decomposition, particularly morphological design, the construction of heterostructures, and monolithic catalyst design used to improve their performance. Moreover, this review proposes further improvement directions based on Cu materials' inherent limitations and practical needs. On this basis, in the foreseeable future, Cu materials will play a greater role. [ABSTRACT FROM AUTHOR]

Cu2S has low lattice thermal conductivity and narrow band gap width, and its excellent thermoelectric performance, low cost, and non-toxic properties have attracted widespread attention in the research field of thermoelectric materials. The present work adopts a combination of hydrothermal synthesis and vacuum sintering to prepare C-Uv S based thermoelectric materials. Through phase and composition characterization, as well as thermoelectric performance testing, the influence of rare earth element Tm doping on the thermoelectric properties of Cu2S based materials has been studied. First-principles calculations are used to develop the band structure and density of states of Cu2S. The results indicate that the hydrothermal synthesis method can obtain Cu：h powders, and the phase transformation occurs during the vacuum sintering process, from the original Cu：n to Cu2S. Tm element doping can significantly improve the crystallization performance of Cu2S powders, and with the increase of doping content, the agglomeration phenomenon of Cu2s gradually disappears. The Seebeck coefficient of Cu2S increases with the increase of Tm doping amount, with Cu2S doped with 2% Tm at a phase transition temperature of 350 °C and the Seebeck coefficient reaching a peak of 1589.71/iV/K. With the increase of doping elements and temperature, the electrical conductivity of Cu2S gradually decreases. The thermal conductivity of Cu2S doped with Tm in the medium to high temperature range has a gradual downward trend. The results showed that the figure of merit of Cu2S doped with 2% Tm increases from 0.1 to 0.4, exhibiting an increase of 300%. [ABSTRACT FROM AUTHOR]

Copper-sulfide-based materials have attracted noteworthy attention as thermoelectric materials due to rich elemental reserves, non-toxicity, low thermal conductivity, and adjustable electrical properties. However, research on the flexible thermoelectrics of copper sulfide has not yet been reported. In this work, we developed a facile method to prepare flexible Mn-doped Cu2−xS films on nylon membranes. First, nano to submicron powders with nominal compositions of Cu2−xMnyS (y = 0, 0.01, 0.03, 0.05, 0.07) were synthesized by a hydrothermal method. Then, the powders were vacuum-filtrated on nylon membranes and finally hot-pressed. Phase composition and microstructure analysis revealed that the films contained both Cu2S and Cu1.96S, and the size of the grains was ~20–300 nm. By Mn doping, there was an increase in carrier concentration and mobility, and ultimately, the electrical properties of Cu2−xS were improved. Eventually, the Cu2−xMn0.05S film showed a maximum power factor of 113.3 μW m−1 K−2 and good flexibility at room temperature. Moreover, an assembled four-leg flexible thermoelectric generator produced a maximum power of 249.48 nW (corresponding power density ~1.23 W m−2) at a temperature difference of 30.1 K, and had good potential for powering low-power-consumption wearable electronics. [ABSTRACT FROM AUTHOR]

Electrochemical sensors, due to their excellent and unique features, are of high interest nowadays for the detection and monitoring of several biological compounds. In such a case, serotonin (SRN), an important neurotransmitter, was herein studied for its detection in biological fluids since its presence is more crucial to be monitored and detected in clinical and medical applications. Several study strategies have been used to determine the chemical and physical properties. The crystalline size of the constructed copper sulfide (Cu2S) material was measured to be 25.92 nm. The Cu2S was fabricated over the working surface and further analyzed for several sensor parameters to be optimized. The charge transfer resistance of the copper sulfide-modified glassy carbon electrode (Cu2S/GCE) was determined to be about 277.0 Ω. With the linear range from about 0.029 μM to 607.6 μM for SRN, the limit of detection (LOD) was calculated as 3.2 nM, with a good sensitivity of 13.23 μA μM−1 cm2. The sensor experienced excellent repeatability, reproducibility, and long-term stability. The fabricated electrode was selective with the presence of different interfering compounds. The real sample analysis, as determined with the regular addition method with human serum and urine samples, revealed a good recovery percentage. Thus, the employed fabricated electrode material will be highly effective in sensing other analytes of choice. [ABSTRACT FROM AUTHOR]

The technique of gold collection in matte can effectively improve the trapping efficiency of precious metals such as gold, silver, and platinum. However, the underlying mechanism of gold collection from high-temperature molten matte is complex and not well understood. In this work, the first-principle calculations were utilized to investigate the adsorption behavior of gold atoms on a Cu2S surface. The effects of vacancies and As and Sb doping on the gold-trapping ability of Cu2S were also explored, and the electronic properties of each adsorption system, including the charge density difference, density of states, and charge transfer, were systematically analyzed. The results show that the Cu-terminated Cu2S(111) surface has the lowest surface energy, and the Au atom is chemically adsorbed on the Cu2S(111) with an adsorption energy of −1.99 eV. The large adsorption strength is primarily ascribed to the strong hybridizations between Au-5d and Cu-3d orbitals. Additionally, the Cu vacancy can significantly weaken the adsorption strength of Cu2S(111) towards Au atoms, while the S vacancy can notably enhance it. Moreover, due to the formation of strong covalent As–Au/Sb–Au bonds, doping As and Sb into Cu2S(111) can enhance the gold-trapping capability of Cu2S, and the Sb doping exhibits superior effectiveness. Our studied results can provide theoretical guidance for improving the gold collection efficiency of Cu2S. [ABSTRACT FROM AUTHOR]

The kinetics of the thermal oxidation of white metal and Cu2S have been studied by thermogravimetric analysis (TG), which was carried out under atmospheric oxidative conditions (O2 100%) with heating rates of 5, 10, 15 and 20 °C min−1. Each experiment was performed three times, the indicated values being the average of the three experiments. The experimental data were evaluated using isoconversional models based on the Arrhenius equation. The models are constructed using first-order mechanisms in the reactions and therefore, since most of them present adequate regression coefficients, it can be verified that order 1 is the most predominant order among the reactions found. In addition, the Kissinger–Akahira–Sunose model, which has the highest regression coefficient, is considered to be the most optimal. Similar behavior was recorded between Cu2S and white metal, as well as a similar regular increase in the apparent activation energy (Ea) of 10–30 kJ mol−1 for both materials. The reactions that took place during the oxidation of white metal and Cu2S were determined using a computational model based on thermodynamics developed in this work. The identified phases include CuSO4, Cu2SO4, Cu2O, CuO, CuO·CuSO4. [ABSTRACT FROM AUTHOR]

In this study, MoS2/Cu2S/PANI with 'wheat ear' structure was synthesized on nickel foam (NF) for electrocatalytic hydrogen production. The experimental results show that the catalyst exhibits excellent HER performance. At a current density of 10 mA cm−2, it only has an overpotential of 98 mV. And it has good durability within 24 h. Compared with other materials, MoS2/Cu2S/PANI has better catalytic performance. There are three reasons for the enhancement of catalytic activity. On the one hand, polyaniline (PANI) has strong conductivity, which can improve the poor conductivity of MoS2. On the other hand, the nitrogen species derived from the PANI structural unit tend to bind metal ions such as Cu2+. Make the active material more evenly dispersed on the substrate. Cu2+ further attracted negatively charged molybdate (MoO42−) to distribute uniformly on the surface of PANI. As a result, the synthesized molybdenum disulfide (MoS2) is not stacked together, the specific surface area becomes larger, and the active sites increase. In addition, Cu2S, as a strong chemical bond between PANI and MoS2, should act as an electron transfer channel in the HER process. All of these make the composites exhibit excellent HER performance and thermal stability. Synthesis mechanism of MoS2/Cu2S/PANI on nickel foam [ABSTRACT FROM AUTHOR]

Abstract At the Hwangnyongsa temple site, which was founded in 633, at Dongdaebong Mountain in Korea, a large number of gilt-bronze artefacts have been excavated. Optical microscopy, X-ray fluorescence, scanning electron microscopy, energy dispersive X-ray spectroscopy, focused ion beam and transmission electron microscopy were used to identify the structure of specimen and impurities. This article investigated the impurities and copper grains in bronze Buddha robes from the Hwangnyongsa temple site to determine the ancient bronze craft technology in the Unified Silla period (seventh–tenth). The XRF results of the specimens indicated that they were made using an alloy of copper and tin, and gold plating was only added on the front side. The microstructure of the specimen was confirmed to be a recrystallized equiaxed hexagonal structure with twins and impurities. The EDS results of the impurities indicated the molar ratio of Cu:S was 2:1, and the electron diffraction pattern substantiated this result by indicating Cu2S (JCPDF 33-0490). The surface of the specimen consisted of a highlead layer and copper grains. It was hypothesized that the copper grains were formed by the reaction of Pb with the matte (Cu2S) during casting. Lead with black gas would aid in the production of high-quality bronze. The copper grains used were found in Silla, as they have been detected in Koryo bronze artefacts. Hence, it is plausible that the ancient artisans knew that lead provided good bronze quality during the casting process.

In this work, flexible Cu2−xS films on nylon membranes are prepared by combining a simple hydrothermal synthesis and vacuum filtration followed by hot pressing. The films consist of Cu2S and Cu1.96S two phases with grain sizes from nano to submicron. Doping Se on the S site not only increases the Cu1.96S content in the Cu2−xS to increase carrier concentration but also modifies electronic structure, thereby greatly improves the electrical properties of the Cu2−xS. Specifically, an optimal composite film with a nominal composition of Cu2−xS0.98Se0.02 exhibits a high power factor of ~150.1 μW m−1 K−2 at 300 K, which increases by ~138% compared to that of the pristine Cu2−xS film. Meanwhile, the composite film shows outstanding flexibility (~97.2% of the original electrical conductivity is maintained after 1500 bending cycles with a bending radius of 4 mm). A four-leg flexible thermoelectric (TE) generator assembled with the optimal film generates a maximum power of 329.6 nW (corresponding power density of 1.70 W m−2) at a temperature difference of 31.1 K. This work provides a simple route to the preparation of high TE performance Cu2−xS-based films.

The threat of ozone in indoor spaces and other enclosed environments is receiving increasing attention. Among numerous ozone catalytic decomposition technologies, copper catalytic material has a superior performance and relatively low cost, making it one of the ideal catalyst materials. This review presents the recent Cu catalyst studies on ozone decomposition, particularly morphological design, the construction of heterostructures, and monolithic catalyst design used to improve their performance. Moreover, this review proposes further improvement directions based on Cu materials’ inherent limitations and practical needs. On this basis, in the foreseeable future, Cu materials will play a greater role.

Porous C nanosheet/Cu2S composites were prepared using a simple self-template method and vulcanization process. The Cu2S nanoparticles with an average diameter of 140 nm are uniformly distributed on porous carbon nanosheets. When used as the anode of a potassium-ion battery, porous C nanosheet/Cu2S composites exhibit good rate performance and cycle performance (363 mAh g−1 at 0.1 A g−1 after 100 cycles; 120 mAh g−1 at 5 A g−1 after 1000 cycles). The excellent electrochemical performance of porous C nanosheet/Cu2S composites can be ascribed to their unique structure, which can restrain the volume change of Cu2S during the charge/discharge processes, increase the contact area between the electrode and the electrolyte, and improve the electron/ionic conductivity of the electrode material. [ABSTRACT FROM AUTHOR]

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[Display omitted] • Nano-Worm-like Cu 2 S is uniformly and well-dispersedly grown at Cu Mesh (CSCM). • CSCM has the macroscale practicality as a mesh and the nanoscale functionality as nanoworms. • Comparisons are made to investigate the structure–property relationship of CSCM. • CSCM exhibits the more superior textural, electrochemical and catalytic properties. • CSCM also enables a lower Ea of C4mim degradation than the reported activation energies. The increasing consumption of room-temperature ionic liquids (RTILs) inevitably releases RTILs into the water environment, posing serious threats to aquatic ecology due to the toxicities of RTILs. Thus, urgent needs are necessitated for developing useful processes for removing RTILs from water, and 1-butyl-3-methylimidazolium chloride (C4mimCl), the most common RTIL, would be the most representative RTIL for studying the removal of RTILs from water. As advanced oxidation processes with hydrogen peroxide (HP) are validated as useful approaches for eliminating emerging contaminants, developing advantageous heterogeneous catalysts for activating HP is the key to the successful degradation of C4mim. Herein, a hierarchical structure is fabricated by growing Cu 2 S on copper mesh (CSCM) utilizing CM as a Cu source. Compared to its precursor, CuO@CM, this CSCM exhibited tremendously higher catalytic activity for catalyzing HP to degrade C4mim efficiently because CSCM exhibits much more superior electrochemical properties and reactive sites, allowing CSCM to degrade C4mim rapidly. CSCM also exhibits a smaller E a of C4mim elimination than all values in the literature. CSCM also shows a high capacity and stability for activating HP to degrade C4mim in the presence of NaCl and seawater. Besides, the mechanistic investigation of C4mim elimination by CSCM-activated HP has also been clarified and ascribed to OH and 1O 2. The elimination route could also be examined and disclosed in detail through the quantum computational chemistry, confirming that CSCM is a useful catalyst for catalyzing HP to degrade RTILs. [ABSTRACT FROM AUTHOR]

Advanced high-performance microwave absorber development now revolves around achieving better microwave absorption performance and intelligent electromagnetic property control. Effectively adjusting electromagnetic microwave dissipation qualities throughout a wide frequency range has been mostly unexplored, particularly for manufactured absorbers. Innovative and high-performance absorber materials are produced and analyzed in this study. Solvothermal preparation is used to synthesize polygonal-shaped CuCo 2 S 4 particles that are embellished with Cu 2 S particles. The permittivity and permeability of polygonal CuCo 2 S 4 particles decorated with Cu 2 S particles are significantly altered, which further affects the nanocomposite's performance in terms of microwave absorption. At a filler loading of 40 wt percent, the composite exhibits exceptional microwave absorption capabilities, and at a thin thickness of 1.5 mm, its effective absorption bandwidth (EAB) approaches 4.5 GHz, covering the whole X-band frequency range. The produced composite has outstanding dissipation qualities owing to the synergistic effects of numerous attenuation mechanisms and hetero-interfaces, where the ideal microwave dissipation strength is up to −32 dB. [ABSTRACT FROM AUTHOR]

Civilization can be shielded from the dangerous electromagnetic spectrum by using microwave absorption materials, however, absorbing electromagnetic radiation with thin thickness and high bandwidth remains a challenge, especially at scales that are significant. Herein, we propose a novel architecture where worm-like Cu 2 S particles are decorating CuCo 2 S 4 micro-spheres were decorated, and this method is thought to be a successful one for enhancing the created nanocomposite's ability to dissipate electromagnetic radiation. Changing the filler loading percentage allows the nanohybrids' electromagnetic characteristics and microwave dissipation effectiveness to be efficiently changed. This leads to the creation of ultra-bandwidth absorbers with thin thickness, which are then tested using waveguide and free-space techniques. The sample with a thickness of 1.4 mm has a maximum reflection loss of −18 dB and a maximum bandwidth of 3.6 GHz. The hetero-structures, multi-interfaces, and multiple relaxations phenomena, as well as the combined effects of the two components, are credited with the superior microwave absorption performance compared with the state-of-the-art. This finding demonstrates that CuCo 2 S 4 /Cu 2 S nanohybrids pave the way for the development of future high-performance microwave absorption materials. [ABSTRACT FROM AUTHOR]

The technique of gold collection in matte can effectively improve the trapping efficiency of precious metals such as gold, silver, and platinum. However, the underlying mechanism of gold collection from high-temperature molten matte is complex and not well understood. In this work, the first-principle calculations were utilized to investigate the adsorption behavior of gold atoms on a Cu2S surface. The effects of vacancies and As and Sb doping on the gold-trapping ability of Cu2S were also explored, and the electronic properties of each adsorption system, including the charge density difference, density of states, and charge transfer, were systematically analyzed. The results show that the Cu-terminated Cu2S(111) surface has the lowest surface energy, and the Au atom is chemically adsorbed on the Cu2S(111) with an adsorption energy of −1.99 eV. The large adsorption strength is primarily ascribed to the strong hybridizations between Au-5d and Cu-3d orbitals. Additionally, the Cu vacancy can significantly weaken the adsorption strength of Cu2S(111) towards Au atoms, while the S vacancy can notably enhance it. Moreover, due to the formation of strong covalent As–Au/Sb–Au bonds, doping As and Sb into Cu2S(111) can enhance the gold-trapping capability of Cu2S, and the Sb doping exhibits superior effectiveness. Our studied results can provide theoretical guidance for improving the gold collection efficiency of Cu2S.

Copper-sulfide-based materials have attracted noteworthy attention as thermoelectric materials due to rich elemental reserves, non-toxicity, low thermal conductivity, and adjustable electrical properties. However, research on the flexible thermoelectrics of copper sulfide has not yet been reported. In this work, we developed a facile method to prepare flexible Mn-doped Cu2−xS films on nylon membranes. First, nano to submicron powders with nominal compositions of Cu2−xMnyS (y = 0, 0.01, 0.03, 0.05, 0.07) were synthesized by a hydrothermal method. Then, the powders were vacuum-filtrated on nylon membranes and finally hot-pressed. Phase composition and microstructure analysis revealed that the films contained both Cu2S and Cu1.96S, and the size of the grains was ~20–300 nm. By Mn doping, there was an increase in carrier concentration and mobility, and ultimately, the electrical properties of Cu2−xS were improved. Eventually, the Cu2−xMn0.05S film showed a maximum power factor of 113.3 μW m−1 K−2 and good flexibility at room temperature. Moreover, an assembled four-leg flexible thermoelectric generator produced a maximum power of 249.48 nW (corresponding power density ~1.23 W m−2) at a temperature difference of 30.1 K, and had good potential for powering low-power-consumption wearable electronics.

Electrochemical sensors, due to their excellent and unique features, are of high interest nowadays for the detection and monitoring of several biological compounds. In such a case, serotonin (SRN), an important neurotransmitter, was herein studied for its detection in biological fluids since its presence is more crucial to be monitored and detected in clinical and medical applications. Several study strategies have been used to determine the chemical and physical properties. The crystalline size of the constructed copper sulfide (Cu2S) material was measured to be 25.92 nm. The Cu2S was fabricated over the working surface and further analyzed for several sensor parameters to be optimized. The charge transfer resistance of the copper sulfide-modified glassy carbon electrode (Cu2S/GCE) was determined to be about 277.0 Ω. With the linear range from about 0.029 μM to 607.6 μM for SRN, the limit of detection (LOD) was calculated as 3.2 nM, with a good sensitivity of 13.23 μA μM−1 cm2. The sensor experienced excellent repeatability, reproducibility, and long-term stability. The fabricated electrode was selective with the presence of different interfering compounds. The real sample analysis, as determined with the regular addition method with human serum and urine samples, revealed a good recovery percentage. Thus, the employed fabricated electrode material will be highly effective in sensing other analytes of choice.

2D Cu 2 S snowflakes and 2D Ni-MOFs flakes were synthesized by hydrothermal method, and Ni-MOFs were calcined with sodium hypophosphite at 200 °C to form Ni-MOFs-P (Ni-MOFs/Ni 2 P). In the physical mixing process, since the -formation temperature of Cu 2 S is at 80 °C, the physical mixing temperature was controlled at 80 °C, which is advantageous for achieving a close 2D/2D contact. The results showed that 15 vol% TEOA with pH = 10 was used as sacrificent reagent under 5 W LED simulated visible light. 20 mg of EY was used as a photosensitizer. CNP60 had the best hydrogen evolution performance within 5 h, which was 3122.76 μmol g−1 h−1. The hydrogen evolution rate of CNP60 is 8.72 fold, 3.37 fold, and 91.85 fold faster than that of Ni-MOFs, Ni-MOFs-P, and Cu 2 S, respectively. Ni-MOFs phosphating and Cu 2 S loading can reduce the photocatalyst's photogenerated electron and hole recombination efficiency. This significant improvement was achieved through XRD, SEM, TEM, XPS, UTV-Visible DRS, transient photocurrent, steady-state fluorescence, short fluorescence, related substance reporting studies, radical hydroxyl trapping, and more. The results show that the 2D/2D assembled CNP can effectively enhance the ability to reduce H∗, and a possible photocatalytic hydrogen production mechanism is proposed. • Ni-MOFs-P and Cu 2 S snowflakes construct 2D/2D structures. • Partial phosphating and construction of 2D Cu 2 S effectively enhance the photocatalytic efficiency. • The Ni-MOFs-P/Cu 2 S photocatalyst has good electrochemical performance. • The optimum hydrogen production rate of the Ni-MOFs-P/Cu 2 S photocatalyst is high. [ABSTRACT FROM AUTHOR]

The effects of CeCu6 and Cu2S on microstructure, electrical conductivity and mechanical properties in as-cast pure copper were investigated by utilizing the microstructure analysis, conductivity test and tensile test with adding 300 ppm Ce and S elements in pure copper ingot (Ce and S elements, mainly existed in the form of CeCu6 and Cu2S). The results showed that the average grain sizes of as-cast pure copper, Cu-0.03Ce and Cu-0.03S were 376, 159 and 193 μm, respectively. The grain refining mechanism of the two phases (CeCu6 and Cu2S) were quite different. The grain refining mechanism of CeCu6 mainly rely on component supercooling; The grain refining mechanism of Cu2S mainly rely on inhibiting grain growth. After hot extrusion, the conductivity of as-cast pure copper, Cu-0.03Ce and Cu-0.03S were increased from 100.1, 100.2 and 95.5 to 101.3, 100.9 and 99.4 %IACS; and the elongation were 66.59, 49.17 and 34.23%, respectively. The disregistry between CeCu6/Cu2S and copper matrix was 10.24% (0 2 10¯)CeCu6‖(4¯ 11)Cu, 24.91% (14¯ 6 12)Cu2S‖(1¯ 31)Cu, respectively. The disregistry between CeCu6 and copper matrix was smaller than that between Cu2S and copper matrix, leading to the wettability, conductivity and interfacial bonding strength between CeCu6 and copper matrix were better. The conductivity of Cu-0.03S could be improved after hot extrusion, which attributed to the gap at the interface could be partially reduced by hot extrusion.

Developing semiconductor substrates with superior stability and sensitivity is challenging in surface-enhanced Raman scattering (SERS) research. Here, a snowflake Cu 2 S@ZIF-67 heterostructure was fabricated using a straightforward method, exhibiting a notable enhancement factor of 9.0 × 109 and a limit of detection (LOD) of 10−14 M for methylene blue (MB). In addition, the Cu 2 S@ZIF-67 heterostructure substrate demonstrates outstanding homogeneity (relative standard deviation (RSD) = 9.2%) and stability (120 days). Employing Cu 2 S generates highly sensitive hotspots via an electromagnetic (EM) mechanism, and the growth of ZIF-67 on its surface augments the adsorption capacity and charge transfer capability (chemical mechanism, CM), thereby enhancing the SERS detection sensitivity. Furthermore, the Cu 2 S@ZIF-67 heterostructure, which was used as a SERS substrate, facilitated the detection of bisphenol A (BPA) with an LOD of 10−11 M. The Cu 2 S@ZIF-67 heterostructure substrate has excellent selectivity and anti-interference, which is very suitable for BPA detection in complex environment applications. The accuracy of the Cu 2 S@ZIF-67 heterostructure as a SERS substrate for detecting BPA in real water samples (water bottles, tap water, and pure milk) was confirmed by comparison with high-performance liquid chromatography (HPLC). These results demonstrate that through the rational design of heterostructures can achieve the quantitative and accurate detection of hazardous substances in food and the environment can be achieved. [Display omitted] • Introduced a novel snowflake Cu 2 S@ZIF-67 heterostructure with significant SERS enhancement. • The optimized Cu 2 S@ZIF-67 presents a significant EF of 9.0 × 109 and LOD is only 10−14 M. • Electron injection reorganizes orbitals, stabilizing the 1 T phase. • Validated accuracy for BPA detection in real samples, outperforming conventional HPLC. • Expanded semiconductor applications in SERS substrate development. [ABSTRACT FROM AUTHOR]

Porous C nanosheet/Cu2S composites were prepared using a simple self-template method and vulcanization process. The Cu2S nanoparticles with an average diameter of 140 nm are uniformly distributed on porous carbon nanosheets. When used as the anode of a potassium-ion battery, porous C nanosheet/Cu2S composites exhibit good rate performance and cycle performance (363 mAh g−1 at 0.1 A g−1 after 100 cycles; 120 mAh g−1 at 5 A g−1 after 1000 cycles). The excellent electrochemical performance of porous C nanosheet/Cu2S composites can be ascribed to their unique structure, which can restrain the volume change of Cu2S during the charge/discharge processes, increase the contact area between the electrode and the electrolyte, and improve the electron/ionic conductivity of the electrode material.

Metal sulfide electrocatalyst is developed as a cost-effective and promising candidate for hydrogen evolution reaction (HER). In this work, we report a novel Mo-doped Cu2S self-supported electrocatalyst grown in situ on three-dimensional copper foam via a facile sulfurization treatment method. Interestingly, Mo-Cu2S nanosheet structure increases the electrochemically active area, and the large fleecy multilayer flower structure assembled by small nanosheet facilitates the flow of electrolyte in and out. More broadly, the introduction of Mo can adjust the electronic structure, significantly increase the volmer step rate, and accelerate the reaction kinetics. As compared to the pure Cu2S self-supported electrocatalyst, the Mo-Cu2S/CF show much better alkaline HER performance with lower overpotential (18 mV at 10 mA cm−2, 322 mV at 100 mA cm−2) and long-term durability. Our work constructs a novel copper based in-situ metal sulfide electrocatalysts and provides a new idea to adjust the morphology and electronic structure by doping for promoting HER performance. [ABSTRACT FROM AUTHOR]

In this work Nano crystalline (Cu2S) thin films pure and doped 3% Al with a thickness of 400±20 nm was precipitated by thermic steaming technicality on glass substrate beneath a vacuum of ~ 2 × 10-6 mbar at R.T to survey the influence of doping and annealing after doping at 573 K for one hour on its structural, electrical and visual properties. Structural properties of these movies are attainment using X-ray variation (XRD) which showed Cu2S phase with polycrystalline in nature and forming hexagonal temple, with the distinguish trend along the (220) grade, varying crystallites size from (42.1-62.06) nm after doping and annealing. AFM investigations of these films show that increase average grain size from 105.05 nm to 146.54 nm while decrease the roughness from 5.93 nm to 4.73 nm after doping. Hall measurements show that the conductivity change from 1.43 × 10-3 to 7.33 × 103 (O cm)-1, these films have p-type conductivity and the mobility varied from 3.87 × 102 to 8.48 × 1010 cm2/V.s. Optical constants were calculated for these films in the range of wave length (300-1100) nm using UV/Visible measurement. The visual properties showed that Cu2S membrane have a high value of the absorption coefficient and decrease the optical energy gap values from (2.25-1.5) eV after doping with 3% Al. The characterization of these films can chose in the application of solar cells. [ABSTRACT FROM AUTHOR]

In recent years, flexible thermoelectric generators(f-TEG), which can generate electricity by environmental temperature difference and have low cost, have been widely concerned in self-powered energy devices for underground pipe network monitoring. This paper studied the Cu2S films by screen-printing. The effects of different proportions of p-type Cu2S/poly 3,4-ethylene dioxythiophene-polystyrene sulfonate (PEDOT:PSS) mixture on the thermoelectric properties of films were studied. The interfacial effect of the two materials, forming a superconducting layer on the surface of Cu2S, leads to the enhancement of film conductivity with the increase of PEDOT:PSS. In addition, the Seebeck coefficient decreases with the increase of PEDOT:PSS due to the excessive bandgap difference between the two materials. When the content ratio of Cu2S and PEDOT:PSS was 1:1.2, the prepared film had the optimal thermoelectric performance, with a maximum power factor (PF) of 20.60 μW·m−1·K−1. The conductivity reached 75% of the initial value after 1500 bending tests. In addition, a fully printed Te-free f-TEG with a fan-shaped structure by Cu2S and Ag2Se was constructed. When the temperature difference (ΔT) was 35 K, the output voltage of the f-TEG was 33.50 mV, and the maximum power was 163.20 nW. Thus, it is envisaged that large thermoelectric output can be obtained by building a multi-layer stacking f-TEG for continuous self-powered monitoring. [ABSTRACT FROM AUTHOR]

[Display omitted] Herein, Cu 2 S as the outer shell is grown on CdS nanorods (NRs) to construct rod-shell nanostructures (CdS/Cu 2 S) by a rapid, scalable and facile cation exchange reaction. The CdS NRs are firstly synthesized by a hydrothermal route, in which thiourea as the precursor of sulfur and ethylenediamine (EDA) as the solvent. And then, the outer shells of CdS NRs are successfully exchanged by Cu 2 S via a cation exchange reaction. The obtained CdS/Cu 2 S rod-shell NRs exhibit much enhanced activity of hydrogen production (640.95 μmol h−1 g−1) in comparison with pure CdS NRs (74.1 μmol h−1 g−1) and pure Cu 2 S NRs (0 μmol h−1 g−1). The enhanced photocatalytic activity of CdS/Cu 2 S rod-shell NRs owns to the following points: i) the photogenerated electrons generated by CdS quickly migrate to Cu 2 S without any barrier due to rod-shell structure by the in-situ cation exchange reaction, a decreased carrier recombination is achieved; ii) Cu 2 S as outer shells broaden the light absorption range of CdS/Cu 2 S rod-shell NRs into visible or even NIR light, which can produce more electrons and holes. This work inspires people to further study the rod-shell structured photocatalyst through the cation exchange strategy to further solar energy conversion. [ABSTRACT FROM AUTHOR]

The self-supporting and flexible Cu2S/poly(3,4-ethylene dioxythiophene):-poly(styrene sulfonate) (PEDOT:PSS) composite thermoelectric films were prepared by vacuum filtration method. The effects of Cu2S content and the pressure of cold-pressing on the thermoelectric properties of composite films were studied. The electrical conductivities of Cu2S/PEDOT:PSS composite films would decrease with the increase of Cu2S content and temperature, while the Seebeck coefficients had an inverse tendency. At the same time, the electrical conductivities and Seebeck coefficients of the Cu2S/PEDOT:PSS composite films will decrease and increases with the increase of temperature, respectively. The maximum power factor (PF) of composite films was 56.15 μWm-1K−2 when Cu2S content was 10 wt% at 393 K. After cold-pressing at 2 MPa or 4 MPa, the PF of 10 wt% composite film was enhanced by two times. The resistance of the cold-pressed composite film would rise only 10 % after bending 1000 cycles under a bending radius of 4 mm, showing good flexibility. The open-circuit voltage and maximum output power were 2.3 mV and 23.06 nW for the TE generator fabricated by four strips of cold-pressed 10 wt% composite film at the temperature difference of 30 K, respectively, which has a good potential to power the low-power consumption wearable electronic devices.

Metal sulfide electrocatalyst is developed as a cost-effective and promising candidate for hydrogen evolution reaction (HER). In this work, we report a novel Mo-doped Cu2S self-supported electrocatalyst grown in situ on three-dimensional copper foam via a facile sulfurization treatment method. Interestingly, Mo-Cu2S nanosheet structure increases the electrochemically active area, and the large fleecy multilayer flower structure assembled by small nanosheet facilitates the flow of electrolyte in and out. More broadly, the introduction of Mo can adjust the electronic structure, significantly increase the volmer step rate, and accelerate the reaction kinetics. As compared to the pure Cu2S self-supported electrocatalyst, the Mo-Cu2S/CF show much better alkaline HER performance with lower overpotential (18 mV at 10 mA cm−2, 322 mV at 100 mA cm−2) and long-term durability. Our work constructs a novel copper based in-situ metal sulfide electrocatalysts and provides a new idea to adjust the morphology and electronic structure by doping for promoting HER performance.

In recent years, flexible thermoelectric generators(f-TEG), which can generate electricity by environmental temperature difference and have low cost, have been widely concerned in self-powered energy devices for underground pipe network monitoring. This paper studied the Cu2S films by screen-printing. The effects of different proportions of p-type Cu2S/poly 3,4-ethylene dioxythiophene-polystyrene sulfonate (PEDOT:PSS) mixture on the thermoelectric properties of films were studied. The interfacial effect of the two materials, forming a superconducting layer on the surface of Cu2S, leads to the enhancement of film conductivity with the increase of PEDOT:PSS. In addition, the Seebeck coefficient decreases with the increase of PEDOT:PSS due to the excessive bandgap difference between the two materials. When the content ratio of Cu2S and PEDOT:PSS was 1:1.2, the prepared film had the optimal thermoelectric performance, with a maximum power factor (PF) of 20.60 μW·m−1·K−1. The conductivity reached 75% of the initial value after 1500 bending tests. In addition, a fully printed Te-free f-TEG with a fan-shaped structure by Cu2S and Ag2Se was constructed. When the temperature difference (ΔT) was 35 K, the output voltage of the f-TEG was 33.50 mV, and the maximum power was 163.20 nW. Thus, it is envisaged that large thermoelectric output can be obtained by building a multi-layer stacking f-TEG for continuous self-powered monitoring.

Hepatitis B virus (HBV) poses a severe threat to public health and social development. Here, we synthesized 4±0.5 nm copper (I) sulfide (Cu2S) nanoparticles (NPs) with 46 mdeg chiroptical property at 530 nm to selectively cleavage HBV core antigen (HBcAg) and effectively blocked HBV assembly and prevented HBV infection both in vitro and in vivo under light at 808 nm. Experimental analysis showed that the chiral Cu2S NPs specific bound with the functional domain from phenylalanine23 (F23) to leucine30 (L30) from HBcAg primary sequence and the cutting site was between amino acid residues F24 and proline25 (P25). Under excitation at 808 nm, the intracellular HBcAg concentration was reduced by 95 %, and in HBV transgenic mice, the levels of HBV surface antigen (HBsAg) and HBV DNA were decreased by 93 % and 86 %, respectively. Together, these results reveal the potential nanomedicine for HBV control and provide fresh tools for viral infection. [ABSTRACT FROM AUTHOR]

[Display omitted] • We develop a multifunctional p-n heterostructure material for SERS substrate. • Low concentrations of pollutants can be rapidly detected within 1 min. • The substrate exhibited excellent practicality in SERS detection. • CMS x has great potential to be cost-efficient wastewater purification materials. Monitoring toxic organic pollutants from water to protect the ecology of water resources is an important and challenging task. For this purpose, snowflake-like n-MoS 2 /p-Cu 2 S heterostructures with sensitivity and stability were synthesized by a simple method. The enhancement factor (EF) of 0.02MoS 2 /Cu 2 S substrate can reach 1.27 × 109 and limit of detection (LOD) is 10−12 M for methylene blue (MB) in lake water. Moreover, the 0.02MoS 2 /Cu 2 S showed excellent photocatalytic activity for degradation of organic pollutants (MB, CV, MG, R6G) which were removed with efficiencies of at least 70–99% within 24 min. This significant EF and photocatalytic performance are mainly attributed to the more "hot spots" offered by the distinctive morphology of Cu 2 S (confirmed by finite-difference time-domain (FDTD) simulation) and the increased charge-separation efficacy of p-n heterojunction owing to the 0.02MoS 2 /Cu 2 S. This study opens up new frontiers for the high-sensitivity detection and complete degradation of organic pollutants. The application of 0.02MoS 2 /Cu 2 S heterostructures to pollution problems provides a cost-effective solution for wastewater treatment. [ABSTRACT FROM AUTHOR]

Metal sulfides are considered excellent materials for oxygen evolution reaction because of their excellent conductivity and high electrocatalytic activity. In this report, the NiS-Cu2S composites were prepared on copper foam (NiS-Cu2S-CF) using a facile synthetic strategy. The scanning electron microscopy results confirmed that the NiS nanoneedles were successfully grown on Cu2S nanoflakes, greatly increasing the active sites. Particularly, the optimized 15% NiS-Cu2S-CF composite demonstrated excellent oxygen evolution activity with a small overpotential of 308 mV@20 mA cm−2, which is significantly smaller than that of noble metal-based electrocatalysts and other NiS-Cu2S-CF composites. The enhanced oxygen evolution activity is attributed to the unique morphology that can provide ample active sites, rich ion-transfer pathways, and the synergistic effect between NiS and Cu2S, which can boost the electron transfer rate.

Cu 2 S likely plays an important role in the sharp resistivity transition of LK-99. Nevertheless, this immediately arouses an intriguing question of whether the extraordinary room-temperature colossal magnetoresistance in the initial reports, which has been less focused, originates from Cu 2 S as well. To resolve this issue, we have systematically investigated the electrical transport and magnetotransport properties of near-stoichiometric Cu 2 S pellets and thin films. Neither Cu 2 S nor LK-99 containing Cu 2 S in this study was found to exhibit the remarkable magnetoresistance effect implied by Lee et al. This implies that Cu 2 S could not account for all of the intriguing transport properties of the initially reported LK-99, and the initially reported LK-99 samples might contain magnetic impurities. Moreover, based on the crystal-structure-sensitive electrical properties of Cu 2 S, we have constructed a piezoelectric-strain-controlled device and obtained a giant and reversible resistance modulation of 2 orders of magnitude at room temperature, yielding a huge gauge factor of 160,000.

In this work, the influence of molar concentration of CuCl2 on copper sulfide Cu2S film synthesized by chemical bath deposition and on the performance of p-Cu2S/p-Si heterojunction photodetector was studied. The effect of copper chloride concentration on the structural, optical properties and electrical properties of Cu2S film was investigated. The optical studies show that the optical energy gap varied from 2.68 to 2.8 eV as the concentration varied from 0.06 to 0.15 M. X-ray diffraction XRD results confirm that the deposition films having of monoclinic chalcocite phase. Scanning electron microscope SEM investigation illustrate the formation of nanostructured Cu2S film with particle size ranged from 50 to80 nm depending on the copper chloride concentration. Two Raman peaks were observed located at 265 and 470 cm−1 assigned to the Cu–S bond vibration and vibrational stretching mode, respectively. The mobility of charge carriers in the film and the electrical conductivity of the film were investigated as a function of copper chloride concentration. Dark and illuminated I-V characteristics of p-Cu2S/p-Si heterojunction HJ photodetectors were measured at room temperature. The best rectification was for heterojunction prepared at 0.13 M CuCl2. The maximum responsivity of the photodetector was about 0.67A/W at 450 nm for photodetector prepared at 0.13 M. [ABSTRACT FROM AUTHOR]

Abstract Liquid‐like materials are one family of promising thermoelectric materials discovered in the past years due to their advantanges of ultrahigh thermoelectric figure of merit (zT), low cost, and environmental friendliness. However, their practial applications are greatly limited by the low service stability from the Cu/Ag metal deposition under large current and/or temperature gradient. Both high zT for high efficiency and large critical voltage for good stability are required for liquid‐like materials, but they are usually strongly correlated and hard to be tuned individually. Herein, based on the thermodynamic analysis, it is shown that such a correlation can be decoupled through doping immobile ions into the liquid‐like sublattice. Taking Cu2−δS as an example, doping immobile Fe ions in Cu1.90S scarcely degrades the initial large critical voltage, but significantly enhances the zT to 1.5 at 1000 K by tuning the carrier concentration to the optimal range. Combining the low‐cost and environmentally friendly features, these Fe‐doped Cu2−δS‐based compounds show great potential in civil applications. This study sheds light on the realization of both good stability and high performance for many other liquid‐like thermoelectric materials that have not been considered for real applications before.

Size- and shape-controlled nanocrystal growth is intensely researched for applications including electro-optic, catalytic, and medical devices. Chemical transformations such as cation exchange overcome the limitation of traditional colloidal synthesis, where the nanocrystal shape often reflects the inherent symmetry of the underlying lattice. Here we show that nanocrystals, with established synthetic protocols for high monodispersity, can be templates for independent composition control. Specifically, controlled interconversion between wurtzite CdS, chalcocite Cu2S, and rock salt PbS occurs while preserving the anisotropic dimensions unique to the as-synthesized materials. Sequential exchange reactions between the three sulfide compositions are driven by the disparate solubilites of the metal ion exchange pair in specific coordinating molecules. Starting with CdS, highly anisotropic PbS nanorods are created, which serve as an important material for studying strong 2-dimensional quantum confinement, as well as for optoelectronic applications. Furthermore, interesting nanoheterostructures of CdS|PbS are obtained by precise control over ion insertion and removal.