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Metal Sulfide Photocatalysis: Visible-Light-Induced Organic Transformations
摘要： Transition-metal sulfides belong to an important subgroup of semiconductor photocatalysts that could promote a variety of valuable redox reactions under mild conditions. One notable merit of metal sulfides is their relatively smaller bandgaps than metal oxides, which in turn make sure that many of them can directly utilize visible light. Historically, the deployment of metal sulfides for visible-light-induced organic transformations took place shortly after the genesis of the research field of heterogeneous photocatalysis. In this review, we primarily focus on recent state-of-the-art advancements of metal sulfide photocatalysis aimed at visible-light-induced selective organic transformations. Interests in this specific branch of photocatalysis have been rekindled due to the new methods for materials synthesis; the pursuit of new mechanisms; or the integration of metal sulfides with metal oxides, metal nanoparticles or other emerging materials. Thus we categorize them into four sections according to the different strategies in developing novel or more efficient organic processes. Binary and ternary metal sulfides, usually associated with new materials synthesis and mechanistic insights, can be used directly for visible-light-induced organic transformations. This is the basis of other further developments and will be introduced firstly. Next, the cooperation between metal sulfides and metal oxides or metal nanoparticles can be conducive to many photocatalytic systems. These developments will be discussed in the next two ensuing sections. Furthermore, the integration of metal sulfides with recent developed emerging materials such as metal-organic frameworks (MOFs), graphene and graphitic carbon nitride (g-C3N4) would be discussed in another section to highlight the importance of merging metal sulfides with these materials. We attempt to keep an impartial panorama of these four distinctive sections even though the phases of development are quite different among sections, leaving plenty of room for the future expansion of this burgeoning area.
关键词： Metal Sulfide,Selective Oxidation,Photocatalysis,Visible Light,Selective Reduction
更新于2025-09-23 15:23:52
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A facile hydrothemal synthesis of MoS2@Co3S4 composites based on metal organic framework compounds as a high-efficiency liquid-state solar cell counter electrode
摘要： A hollow Co3S4 polyhedral loads MoS2 nanosheet composite MoS2@Co3S4-0.5 is prepared by hydrothermal method using Co-based metal organic framework material ZIF-67 as precursor. Hollow Co3S4 polyhedron and uniformly distributed MoS2 nanosheet structure can not only prevent MoS2 aggregation, but also increase the specific surface area of the material and expose more catalytically active sites. The composites afford a promising synergistic effect on the catalyzing of triiodide reduction. As a counter electrode material applied to dye-sensitized solar cells, MoS2@Co3S4-0.5 exhibits excellent catalytic activity, achieving a photoelectric conversion efficiency of 7.86%, which is superior to 6.99% of Pt counter electrode performance in dye-sensitized solar cells. This indicates that MoS2@Co3S4-0.5 composite material can be used to replace precious metal Pt as an efficient and low-cost counter electrode material in dye-sensitized solar cells.
关键词： metal-organic framework,facile hydrothemal synthesis,transition metal sulfide,dye-sensitized solar cells,counter electrode
更新于2025-09-23 15:19:57
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Direct fabrication of Cd–In–S alloy quantum dots thin films
摘要： In this article, a new simple one-step process to fabricate Cd–In–S luminescent quantum dot thin films (QDTFs) is provided. Metal sulfide precursor solutions were manufactured by directly adding a certain amount of butylamine and carbon disulfide in the ethanol solution followed by dissolving Cd(OH)2 and In(OH)3 powder. Cd–In–S luminescent QDTFs can be obtained by mixing Cd and In precursor solutions and then spinning on a cover slip and annealing on a hot plate at 190 °C under air atmosphere directly without complicated synthesis method. By changing the sintering parameters including the temperature, time and ratios of (Cd+In)/ligand, the Cd–In–S luminescent QDTFs covering the entire visible light wavelength from 470 to 628 nm can be obtained. The Cd–In–S luminescent QDTFs exhibited remarkable optical properties and has potential application in solar cell and light emitting diode, with the photoluminescence quantum yield of up to 36.5%.
关键词： metal sulfide precursor solution approach,Cd–In–S,Quantum dots thin films
更新于2025-09-23 15:19:57
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Speciation Analysis of Ag2S- and ZnS-Nanoparticles at ng/L Level in Environmental Waters by Cloud Point Extraction Coupled with LC-ICPMS
摘要： Toxicity and transport of metal-based nanoparticles (M-NPs) in environmental waters strongly depend on their speciation. A detailed understanding of the composition and speciation of M-NPs is necessary in order to move this field forward. Unfortunately, there is a shortage of analytical methods for metal-sulfide nanoparticles (MS-NPs) in the environment. In this work, a cloud point extraction (CPE) method combined with liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (LC-ICPMS) is developed for sensitive determination of Ag2S- and ZnS-NPs. Under the condition of 0.15% (w/v) of Triton X-114 (TX-114), pH 5, 20 mM NaNO3, incubation temperature of 45 oC and time of 15 min, MS-NPs and non-MS-NPs were extracted into the surfactant-rich phase. With the sequent addition of 10 mM bis(p-sulfonatophenyl)phenylphosphane dehydrate dipotassium (BSPP) aqueous solution (100 μL) into the CPE-obtained extract, the non-MS-NPs were selectively dissociated into their ionic counterparts while maintaining the original size and shape of Ag2S- and ZnS-NPs. Interestingly, the micelle-mediated behavior suddenly disappeared with the addition of BSPP. Thus, the extract can be injected to LC-ICPMS for speciation analysis of trace Ag2S- and ZnS-NPs. This method exhibited excellent reproducibility (relative standard deviations < 4.9%), high sensitivity with the respective detection limits of 8 ng/L for Ag2S-NPs and 15 ng/L for ZnS-NPs, enabling recoveries of 81.3-96.6% for Ag2S-NPs and 83.9-93.5% for ZnS-NPs when they were spiked into three environmental water samples. Due to its potential applicability to low concentrations of Ag2S- and ZnS-NPs, this method is particularly convenient for monitoring the transformations of AgNPs and ZnO-NPs in the environment.
关键词： cloud point extraction,LC-ICPMS,environmental waters,metal-sulfide nanoparticles,speciation analysis
更新于2025-09-23 15:19:57
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Highly transparent nickel and iron sulfide on nitrogen-doped carbon films as counter electrodes for bifacial quantum dot sensitized solar cells
摘要： Semiconductors are widely used as counter electrodes in quantum dot-sensitized solar cells. However, many counter electrode materials have poor conductivity and require tedious post-treatment procedures. Here, our groups develop a highly transparent MS2@N-doped C film materials (M = Ni, Fe) derived from layer-by-layer self-assembly of a M-TCPP film as a counter electrode in bifacial CdS/CdSe quantum dot-sensitized solar cells. Devices based on the MS2@N-doped C films exhibited higher respective front- and reverse-side power conversion efficiencies (i.e., 4.57% and 3.98% for the NiS2@N-doped C film and 3.18% and 2.63% for the FeS2@N-doped C film) than those of Pt-based devices (2.39% and 1.74%). We attribute the outstanding catalytic activity and excellent stability of the MS2@N-doped C film materials to the homogeneous sulfides within the transparent nitrogen-doped C film, as confirmed by electrochemical analyses, including cycle voltammetry, impedance spectroscopy and Tafel-polarization measurements.
关键词： Nitrogen doped C film,Metal sulfide,Quantum dot-sensitized solar cells,Counter electrode
更新于2025-09-19 17:13:59
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Low- and High-Order Nonlinear Optical Characterization of Metal Sulfide Quantum Dots
摘要： Any new synthesized semiconductor nanoparticles or quantum dots (QDs) require to be examined under different conditions using laser pulses of variable energies, wavelengths and durations to understand the nonlinear optical mechanisms and distinguish their attractive properties for practical applications. Among various QDs, the metal sulfides took special attention due to their advanced nonlinear optical properties. Additionally, laser ablation can readily produce plasmas containing QDs that could be used for different applications. One of them is that they can be used as emitters for harmonic generation from ultrashort laser pulses. Here we review recent studies of different low- and high-order optical nonlinearities of metal sulfide QDs, such as optical limiting, two-photon, saturable and reverse saturable types of nonlinear absorption, nonlinear refraction, and generation of high-order harmonics in extreme ultraviolet range.
关键词： metal sulfide quantum dots,nonlinear optics
更新于2025-09-12 10:27:22
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Bandgap Tunable Ternary Cd <sub/><i>x</i> </sub> Sb <sub/> 2– <i>y</i> </sub> S <sub/>3?δ</sub> Nanocrystals for Solar Cell Applications
摘要： We report the synthesis and photovoltaic performance of a new nonstoichiometric ternary metal sulfide alloyed semiconductor?CdxSb2?yS3?δ nanocrystals prepared by the two-stage sequential ionic layer adsorption reaction technique. The synthesized CdxSb2?yS3?δ nanocrystals retain the orthorhombic structure of the host Sb2S3 with Cd substituting a fraction (x = 0?0.15) of the cationic element Sb. The CdxSb2?yS3?δ lattice expands relative to the host, Sb2S3, with its lattice constant a increasing linearly with Cd content x. Optical and external quantum efficiency (EQE) spectra revealed that the bandgap Eg of CdxSb2?yS3?δ decreased from 1.99 to 1.69 eV (i.e., 625?737 nm) as x increased from 0 to 0.15. Liquid-junction CdxSb2?yS3?δ quantum dot-sensitized solar cells were fabricated using the polyiodide electrolyte. The best cell yielded a power conversion efficiency (PCE) of 3.72% with the photovoltaic parameters of Jsc = 15.97 mA/cm2, Voc = 0.50 V, and FF = 46.6% under 1 sun. The PCE further increased to 4.86%, a respectable value for a new solar material, under a reduced light intensity of 10% sun. The PCE (4.86%) and Jsc (15.97 mA/cm2) are significantly larger than that (PCE = 1.8%, Jsc = 8.55 mA/cm2) of the Sb2S3 host. Electrochemical impedance spectroscopy showed that the ZnSe passivation coating increased the electron lifetime by three times. The EQE spectrum of CdxSb2?yS3?δ has a maximal EQE of 82% at λ = 350 nm and covers the spectral range of 300?750 nm, which is significantly broader than that (300?625 nm) of the Sb2S3 host. The EQE-integrated current density yields a Jph of 11.76 mA/cm2. The tunable bandgap and a respectable PCE near 5% suggest that CdxSb2?yS3?δ could be a potential candidate for a solar material.
关键词： ternary metal sulfide,CdxSb2?yS3?δ nanocrystals,photovoltaic performance,quantum dot-sensitized solar cells,bandgap tunable
更新于2025-09-12 10:27:22
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Spontaneous Growth of Au Nanoparticles onto CdS, ZnS or PbS Thin Films for Electrochemical Immunosensors
摘要： A facile method to fabricate Au-CdS (or ZnS, PbS) nanocomposites is reported. The method is based on spontaneous growth of Au onto the metal sulfide nanoparticles. Unlike typical synthesis of Au-semiconductor nanocomposites, this method does not require additional steps of introducing other reducing agents. Direct redox reactions occurs between Au(III) ions and metal sulfide nanoparticles. We have probed the Au-semiconductor nanocomposites by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). A possible mechanism was proposed for spontaneous growth of Au nanoparticles. It was found that H2O2 appeared to inhibit the Au growth onto the metal sulfide surface. We accordingly developed an enzyme-linked sandwich electrochemical immunosensor for the detection of human immunoglobulin G (IgG). In the electrochemical immunosensor, we use the glucose oxidase labeled antibody to generate H2O2 that inhibits the Au growth on CdS films, thereby decreasing the cathodic current at 0.9 V. This immunosensor can detect IgG as low as 1.5 ng/mL.
关键词： Spontaneous growth,metal sulfide,Au-CdS nanocomposites
更新于2025-09-10 09:29:36