Mixed Sulfur Research Articles

Fabrication and characterization of ZnS and ZnSe absorber layers for UV-selective transparent photovoltaics

We have fabricated ZnS, ZnSe and mixed Zn(S,Se) thin film layers for application as solar cell absorbers in ultraviolet (UV)-selective solar cells. We fabricated the thin film layers using a two-step process involving evaporation of the Zn layer followed by an anneal in an H2S and/or H2Se containing atmosphere. A study of the annealing conditions was performed to minimize hole formation in the thin film layer. A mixed Sulfur and Selenium containing layer was also developed in order to reach a 3 eV band gap, such that the layer absorbs all the UV light and leaves the visible light passing through. Next, we tried to increase the conductivity of the layer by adding extrinsic doping elements. Cu was found to increase the conductivity by more than three orders of magnitude, while leaving the transparency of the layer mostly unchanged. Finally, solar cell devices were fabricated using transparent back and front contacts and a NiO buffer layer. We could measure a very small photocurrent of about 100 μA/cm2 and an open circuit voltage of about 500 mV under AM1.5 G illumination.

Influence of Mixed Sulfur and Peroxide Curing Systems on Cross‐Linking and Properties of Rubber Compounds Based on EPDM

AbstractIn this work, sulfur vulcanization system, peroxide vulcanization system, and combined sulfur and peroxide curing systems are applied for cross‐linking of rubber compounds based on ethylene propylene diene monomer rubber. The goal is to investigate the influence of curing system composition on cross‐linking and properties of rubber formulations. The combination of both vulcanization systems in cross‐linking of rubbers combines the pattern of carbon–carbon linkages and sulfidic bridges, which gives the real presumption to modify physical–mechanical properties of final vulcanizates. The results reveal that the combination of vulcanization systems affects the curing characteristics, cross‐link density as well as physical–mechanical properties of tested materials. In comparison with vulcanizates cured only with sulfur or peroxide system, rubber compounds cross‐linked with mixed sulfur and peroxide curing systems exhibite higher tensile strength and elongation at break.

Polyamidoamine dendrimer modified Ketjen Black mixed sulfur coated cathode for enhancing polysulfides adsorbability in Li-S batteries

Lithium sulfur (Li-S) batteries were considered the next generation of energy devices with the greatest development potential because of their large theoretical capacity and high energy density. However, many challenges exist in the research field of Li-S batteries, such as low utilization rate of active substances and inferior cycling performance. Here, a simple and feasible preparation strategy was applied to fabricate the composite cathode of polyamidoamine (PAMAM) dendritic macromolecule polymer modified the Ketjen Black mixed sublimated sulfur (PAMAM@KB@S). Benefiting from the improved polysulfides adsorbability due to the abundant functional groups which originate from PAMAM, PAMAM@KB@S composites with 3.94 mg sulfur-loading at a current density of 0.5 C exhibit a high initial specific discharge capacity of 894.3 mAh g−1 and maintain a specific discharge capacity of 455.7 mAh g−1 after 200 cycles. And the average Coulombic efficiency of PAMAM@KB@S electrode (96.7%) within 200 cycles is higher than that of KB@S electrode (88.5%).

Field-induced single-ion magnet based on a quasi-octahedral Co(II) complex with mixed sulfur-oxygen coordination environment.

Synthesis and characterization of structure and magnetic properties of the quasi-octahedral complex (pipH2)[Co(TDA)2] 2H2O (I), (pipH22+ = piperazine dication, TDA2- = thiodiacetic anion) are described. X-ray diffraction studies reveal the first coordination sphere of the Co(II) ion, consisting of two chelating tridentate TDA ligands with a mixed sulfur-oxygen strongly elongated octahedral coordination environment. SQUID magnetometry, frequency-domain Fourier-transform (FD-FT) THz-EPR spectroscopy, and high-level ab initio SA-CASSCF/NEVPT2 quantum chemical calculations reveal a strong "easy-plane" type magnetic anisotropy (D ≈ +54 cm-1) of complex I. The complex shows field-induced slow relaxation of magnetization at an applied DC field of 1000 Oe.

Combined sulfur and peroxide curing systems applied in cross-linking of rubber magnets

In the present work, barium ferrite in constant loading was dosed to the rubber matrices based on NR, SBR and NBR. Sulfur, peroxide and mixed sulfur and peroxide curing systems were applied for cross-linking of rubber magnetic composites. The application of sulfur or peroxide curing system leads to the formation of different types of linkages between rubber chain segments. As the structure of the formed cross-links plays a significant role in determining the final properties of rubber articles, the main aim of the work was to use the combination of curing systems in order to suppress the disadvantages of both systems and possibly to highlight their benefits. The results showed that composition of curing system has considerable influence on cross-link density of composites, which was subsequently reflected in typical change of physical-mechanical properties and glass transition temperature. The tensile strength was improved with increasing amount of peroxide curing system. The reason can be attributed to the presence of co-agent zinc methacrylate, which exhibits strong adhesion to magnetic filler and thus it contributes to the improvement of compatibility and homogeneity on the interphase filler–rubber. On the hand, there was observed no influence of curing system composition or type of rubber matrix on magnetic characteristics of composites.

In-situ quadruple sulfur isotopic compositions of pyrites in the ca. 3.2–2.72 Ga metasedimentary rocks from the Pilbara Craton, Western Australia

The sulfur mass independent fractionation (S-MIF) of Mesoarchean is distinct from the other Archean periods by the dampened magnitudes of Δ33S and a steeper slope of Δ36S/Δ33S compared with the Archean Reference Array (ARA) according to previous studies. However, samples available of this interval are limited owing to poor or no preservation. Additionally, the majority of the data were obtained by analysis of bulk rocks, thus are essentially the sulfur isotopic compositions of mixed sulfur components due to multiple stages of post-diagenesis overprints and modifications. This study systematically measured the multiple sulfur isotopic compositions of pyrites (nodular, disseminated) in ca. 3.2–2.72 Ga metasedimentary rocks from the Pilbara Craton, Western Australia, where one of the best-preserved Archean records occur, using the upgraded SHRIMP-SI, after detailed pyrite generation and genesis investigation by BSE imaging and NaOCl etching. The results show that Δ33S values of the diagenetic pyrites in these metasedimentary rocks range from −2.4 to 0.8‰. Such a range is inconsistent with the other Archean intervals and any experiment producing S-MIF so far, where the magnitude of the maximum positive Δ33S value is considerably larger than the corresponding minimum negative Δ33S value. The dampened positive Δ33S is explained in several ways from the perspective of production and preservation, including original photochemical products with larger magnitudes of negative Δ33S than positive Δ33S in a different atmospheric composition, non-zero Δ33S of initial SO2, different mechanism producing S-MIF (chain formation), and destruction of positive Δ33S by subduction. The downward Δ36S/Δ33S deviations from ARA in the diagenetic pyrites of 2.72 Ga Tumbiana Formation can be attributed to modifications induced by microbial activities. This is based on the negative (0.9Δ33S + Δ36S) values similar to biological products and the large range of negative δ34S values. The downward Δ36S/Δ33S offsets in the hydrothermally altered diagenetic pyrites of 2.78 Ga Mt. Roe Basalt are most likely mixing of primary sulfur on ARA with later sulfur disobeying ARA. The upward Δ36S/Δ33S deviations in the diagenetic pyrites of 2.93 Ga Mosquito Creek Formation likely reflect different atmospheric composition.

Cover Feature: Symmetric Mixed Sulfur–Selenium Fused Ring Systems as Potential Materials for Organic Field‐Effect Transistors (Chem. Eur. J. 13/2020)

Cover Feature: Symmetric Mixed Sulfur–Selenium Fused Ring Systems as Potential Materials for Organic Field‐Effect Transistors (Chem. Eur. J. 13/2020)

Adopting Mixed Sulfur and Selenium Chalcogenides As High Energy Density Copolymer Cathodes in Rechargeable Sodium Metal Systems

The ever increasing demand for energy storage has encouraged exploration of battery systems with higher energy density and lower cost than Li-ion batteries.1 This work reveals the very first demonstration of a room temperature, sodium/polymeric mixed-chalcogenide battery. The chemistry is enabled by crosslinking of sulfur and selenium, which maintains the elemental mixture in long chains instead of crystalline rings, for a mechanistically different conversion cathode. Room temperature Li-S batteries, which boast ultra-high energy density (~2600 Wh/kg) and low cost/highly abundant sulfur, are expected to succeed the intercalation Li-ion battery (<400 Wh/kg), but to-date deliver impractical cycle life due to active material dissolution. The novel chain assembly provided by crosslinking prevents this behavior, enabling extensive cycle life.2 Herein the crosslinker type and molecular ratio are modulated for optimal chain length and performance. Furthermore, selenium delivers 20 orders of magnitude greater electrical conductivity than sulfur.3 The atomic ratio of sulfur to selenium is modulated for a balance of electrical conductivity and energy density. Notably, these cathodes are simplistically processed at temperatures below 200 ˚C. The crosslinked, mixed chalcogenide cathodes are paired with metallic sodium anodes, that are 3 orders of magnitude more abundant than lithium metal,1 and exhibit favorable plating behavior in the system-prescribed, ether-based electrolytes.4 This full cell touts a theoretical energy density of ~1000 Wh/kg and effective incorporation of highly abundant raw materials. Hong, X.; Mei, J.; Wen, L.; Tong, Y.; Vasileff, A. J.; Wang, L.; Liang, J.; Sun, Z.; Dou, S. X., Nonlithium Metal–Sulfur Batteries: Steps Toward a Leap. Advanced Materials 0 (0), 1802822.Simmonds, A. G.; Griebel, J. J.; Park, J.; Kim, K. R.; Chung, W. J.; Oleshko, V. P.; Kim, J.; Kim, E. T.; Glass, R. S.; Soles, C. L.; Sung, Y.-E.; Char, K.; Pyun, J., Inverse Vulcanization of Elemental Sulfur to Prepare Polymeric Electrode Materials for Li–S Batteries. ACS Macro Letters 2014, 3 (3), 229-232.Abouimrane, A.; Dambournet, D.; Chapman, K. W.; Chupas, P. J.; Weng, W.; Amine, K., A New Class of Lithium and Sodium Rechargeable Batteries Based on Selenium and Selenium–Sulfur as a Positive Electrode. Journal of the American Chemical Society 2012, 134 (10), 4505-4508.Seh, Z. W.; Sun, J.; Sun, Y.; Cui, Y., A Highly Reversible Room-Temperature Sodium Metal Anode. ACS Central Science 2015, 1 (8), 449-455.

Mixed Sulfur and Iodide-Based Lead-Free Perovskite Solar Cells.

The use of divalent chalcogenides and monovalent halides as anions in a perovskite structure allows the introduction of 3+ and 4+ charged cations in the place of the 2+ metal cations. Herein we report for the first time on the fabrication of solar cells exploiting methylammonium antimony sulfur diiodide (MASbSI2) perovskite structures, as light harvesters. The MASbSI2 was prepared by annealing under mild temperature conditions, via a sequential reaction between antimony trisulfide (Sb2S3), which is deposited by the chemical bath deposition (CBD) method, antimony triiodide (SbI3), and methylammonium iodide (MAI) onto a mesoporous TiO2 electrode, and then annealed at 150 °C in an argon atmosphere. The solar cells fabricated using MASbSI2 exhibited power conversion efficiencies (PCE) of 3.08%, under the standard illumination conditions of 100 mW/cm2.

Sources of fluids and metals and evolution models of skarn deposits in the Qimantagh metallogenic belt: A case study from the Weibao deposit, East Kunlun Mountains, northern Tibetan Plateau

The Weibao Cu-Pb-Zn deposit is typical of skarn deposits in the Qimantagh metallogenic belt (QMB), East Kunlun Mountains, northern Tibetan Plateau. It comprises three ore blocks from west to east, known as Weixi, Main and Weidong. Mineralization in the Weibao deposit is intimately related to Late Triassic intrusions occurring at Weixi and Weidong, and orebodies are predominantly hosted by the Langyashan Formation (marine carbonate rocks), and to a lesser extent the Devonian volcanic rocks. Skarns from Weixi and Weidong are characterized by a high garnet/pyroxene ratio and diopside- and andradite-rich composition of pyroxenes and garnets, indicating a proximal, oxidized type. In contrast, skarn mineralogy of Main indicates a slightly reduced condition, typical of Pb-Zn skarn deposits. At least five hydrothermal mineralization stages can be identified and the microthermometric study indicates a general trend of cooling and dilution of the magmatic-hydrothermal fluids. Significant precipitation of Cu-Fe sulfides commenced from the fluid with the temperature of 340–448 °C and the salinity of 2.1–15.0 wt% NaCl equiv. Pb-Zn sulfides however mainly precipitated when the temperatures declined to <370 °C and the salinity declined to <7.6 wt% NaCl equiv. Carbon, hydrogen and oxygen isotopic composition of the fluids suggests a predominantly igneous source for the initial fluids, which were modified outward by fluid-rock interaction and mixing with meteoric waters. Both sulfur and lead isotope composition of sulfides supports a mixed sulfur and metal reservoir consisting of Triassic intrusive rocks and wall rocks. Compared to early skarn-forming and late quartz-carbonate stages, two ore-forming stages show clear evidence of fluid boiling and fluid-rock interaction. Combined with microthermometric data of ore-forming stages, it can be deduced that fluid cooling, boiling and fluid-rock interaction were responsible for the significant metal precipitation. The Weibao deposit shows many similarities with skarn deposits in the QMB, and its genetic model therefore can be extrapolated to other skarn deposits in this region.

Development of smart colourimetric starch–based indicator for liberated volatiles during durian ripeness

The mechanical, physical and barrier properties of colourimetric starch–based films (CSBFs) were developed by adding natural polymers (chitosan, citric acid, carboxymethylcellulose, and kraft fibre). Novel volatile compound indicator films were prepared from starch (as a film matrix with 30% w/w sorbitol) using the casting method and adding natural polymers, and pH–dye (methyl red and bromothymol blue as indicators). CSBFs mixed with 0.1% chitosan improved the mechanical and barrier properties with a significant decrease in water vapour transmission rate, water solubility, and oxygen transmission rate, as well as improved tensile strength. Trials using liberated fruit aromas verified that CSBFs resulted in visible colour changes in the presence of mixed sulphur and ethyl alcohol aromas. Colour change in terms of the total colour difference of CSBFs was related to mixed sulphur and ethyl alcohol levels, thereby enabling CSBFs could be used to monitor real–time ripeness of durian volatiles.

ChemInform Abstract: Recent Developments in the Thiamacrocyclic Chemistry of the Latter D‐Block Elements

AbstractReview: 143 refs.

Deep extractive desulfurization of oil over 12-molibdophosphoric acid encapsulated in metal-organic frameworks

A desulfurization process for model oil and real oil was investigated based on the chemical oxidation of mixed sulfur containing compounds in the presence of nitrogen compounds (indole and quinoline) using hydrogen peroxide as oxidizing agent and dodecamolibdophosphoric acid (H3PMo12O40) encapsulated in a kind of metal-organic framework (HKUST-1) as PMo@HKUST-1. The effect of isopropanol, ethanol and acetonitrile as extractive solvent and 1-ring (toluene, xylene and mesitylene) and 2-ring (naphthalene) aromatic hydrocarbons in desulfurization of model oil was studied. The desulfurization of sulfur-containing compounds was accelerated in the presence of aro- matic hydrocarbons. In fact, a higher desulfurization efficiency of the heterogeneous catalyst could be achieved with system containing a polar solvent in contact with an aromatic hydrocarbon. Quinoline had no effect on oxidative desulfurization (ODS) reaction, whereas indole had a slightly negative effect. Presence of aromatic compounds had slightly positive effect on ODS reaction.

Mixed sulfur-iron particles packed reactor for simultaneous advanced removal of nitrogen and phosphorus from secondary effluent.

A mixed sulfur-iron particles packed reactor (SFe reactor) was developed to simultaneously remove total nitrogen (TN) and total phosphorus (TP) of the secondary effluent from municipal wastewater treatment plants. Low effluent TN (<1.5mg/L) and TP (<0.3mg/L) concentrations were simultaneously obtained, and high TN removal rate [1.03gN/(L·d)] and TP removal rate [0.29g P/(L·d)] were achieved at the hydraulic retention time (HRT) of 0.13h. Kinetic models describing denitrification were experimentally obtained, which predicted a higher denitrification rate [1.98gN/(L·d)] of SFe reactor than that [1.58gN/(L·d)] of sulfur alone packed reactor due to the mutual enhancement between sulfur-based autotrophic denitrification and iron-based chemical denitrification. A high TP removal obtained in SFe reactor was attributed to chemical precipitation of iron particles. Microbial community analysis based on 16S rRNA revealed that autotrophic denitrifying bacteria Thiobacillus and Sulfuricella were the dominant genus, indicating that autotrophic denitrification played important role in nitrate removal. These results indicate that sulfur and iron particles can be packed together in a single reactor to effectively remove nitrate and phosphorus.

Research on Au-Bearing Copper Ore in Flotation from Yunnan

In this study, the main aims were to recovery copper from Au-bearing Copper Ore by flotation. The main mineral is copper with 1.18% Cu and 0.75g/t Au. Same chalcopyrite in fine parts is encapsulated in gangue minerals, and some copper minerals exist as the intergrowth with pyrrhotite and pyrite. After study, the suitable mineral combined processing flowsheet of mixed flotation-copper sulphur separation with stage grinding and stage separation which consisting of one rougher-five concentrate-four scavenging flotation and highly efficient collector YL-3 developed independently,which has not only good selectivity for collecting copper, but also can increase Au recovery have been defined. Under such a condition, the grade of Cu is 13.05% and the recovery of 84.94% with Au 5.96g/t and 60.23% recovery is obtained, which has a better effect.

Influence of Curing Systems on Mechanical, Dynamic, and Morphological Properties of Dynamically Cured Epoxidized Natural Rubber/ Copolyamide Blends

Thermoplastic elastomers (TPEs) based on dynamically cured epoxidized natural rubber/copolyamide (ENR/COPA) blends were prepared. Influence of curing systems (i.e., sulphur, peroxide, mixed sulphur and peroxide and phenolic resin cured systems on mechanical, dynamic and morphological properties of the blends were investigated. It was found that the blend with phenolic cured system exhibited superior mechanical and set properties. That is higher tendency to recover to its original shape after a prolong extension. It was also found that the blend with peroxide cured system exhibited higher storage modulus and complex viscosity than those of the blends with mixed sulphur and peroxide, phenolic and sulphur cured system, respectively. Furthermore, the TPVs blend with peroxide cured system showed the smallest vulcanized rubber particles.

Sulphur–carbon composites for Li/S batteries

Structural and electrochemical properties of various types of sulphur–carbon composites were reviewed to propose approaching ways for the development of lithium/sulphur battery with high energy density and good cycle performance. To improve the electrochemical properties of a sulphur cathode, carbon and polymer materials are applied to sulphur composites: multiwalled nanotube (MWNT), graphene, CMK-3 and activated carbon; and polyaniline (PANi), polyacrylonitrile and polythiophene (PTh). These can serve conducting paths and a polysulphide reservoir to enhance the electrical conductivity of the sulphur cathode and effectively prevent dissolution of polysulphides. And the composites are categorised in two parts such as mixed type sulphur composites and embedded type sulphur composites. Among the sulphur–carbon composites, the hollow carbon capsule/S composite prepared by a geometric control and an infusion method of sulphur in sulphur carbon composite electrode, demonstrated the best electrochemical properties.

Electronic Structure of the Thiophene/Au(111) Interface Probed by Two-Photon Photoemission

The electronic structure of thiophene adsorbed on Au(111) has been investigated by two-photon photoemission (2PPE) spectroscopy and density functional theory (DFT) calculations. The dominant interfacial feature observed in the 2PPE spectra is a nondispersive unoccupied state whose width and energy (referenced to the Fermi level) decrease with increasing coverage. We assign this feature to a thiophene LUMO-derived state of mixed sulfur and carbon p−π character. DFT calculations indicate that the experimentally observed decrease in width of this state with increasing coverage is a result of weakening of the thiophene−Au(111) interaction. Increasing the molecular density forces the thiophene plane to tilt away from the surface, rotating the molecular orbitals away from an orientation more favorable for S−Au and π−Au hybridization. We attribute the ∼0.2 eV shift of the LUMO toward the Fermi level to stabilization of the transient anion due to the increasing effect of charge-induced polarization of the neighbo...

Arsenic microdistribution and speciation in toenail clippings of children living in a historic gold mining area

Arsenic is naturally associated with gold mineralisation and elevated in some soils and mine waste around historical gold mining activity in Victoria, Australia. To explore uptake, arsenic concentrations in children's toenail clippings and household soils were measured, and the microdistribution and speciation of arsenic in situ in toenail clipping thin sections investigated using synchrotron-based X-ray microprobe techniques. The ability to differentiate exogenous arsenic was explored by investigating surface contamination on cleaned clippings using depth profiling, and direct diffusion of arsenic into incubated clippings. Total arsenic concentrations ranged from 0.15 to 2.1 µg/g ( n = 29) in clipping samples and from 3.3 to 130 µg/g ( n = 22) in household soils, with significant correlation between transformed arsenic concentrations (Pearson's r = 0.42, P = 0.023) when household soil was treated as independent. In clipping thin sections ( n = 2), X-ray fluorescence (XRF) mapping showed discrete layering of arsenic consistent with nail structure, and irregular arsenic incorporation along the nail growth axis. Arsenic concentrations were heterogeneous at 10 × 10 µm microprobe spot locations investigated (< 0.1 to 13.3 µg/g). X-ray absorption near-edge structure (XANES) spectra suggested the presence of two distinct arsenic species: a lower oxidation state species, possibly with mixed sulphur and methyl coordination (denoted As ≈ III (–S, –CH3)); and a higher oxidation state species (denoted As ≈ V (–O)). Depth profiling suggested that surface contamination was unlikely ( n = 4), and XRF and XANES analyses of thin sections of clippings incubated in dry or wet mine waste, or untreated, suggested direct diffusion of arsenic occurred under moist conditions. These findings suggest that arsenic in soil contributes to some systemic absorption associated with periodic exposures among children resident in areas of historic gold mining activity in Victoria, Australia. Future studies are required to ascertain if adverse health effects are associated with current levels of arsenic uptake.

Effect of vulcanization systems on properties and recyclability of dynamically cured epoxidized natural rubber/polypropylene blends

Thermoplastic vulcanizates (TPVs) based on dynamically cured ENR/PP with various vulcanization systems were prepared. Rheological, mechanical, dynamic and morphological properties of the TPVs were investigated. Amongst the TPVs with peroxide, sulfur and mixed sulfur peroxide cure systems, the TPVs with peroxide cured system showed the lowest apparent stress, shear viscosity, elastic modulus and mechanical strength, whilst the mixed sulfur peroxide curing system showed the highest values with the sulfur cured system being intermediate. However, it was found that the phenolic containing cure systems (i.e., phenolic cured system with HRJ-10518 and mixed phenolic cure system with 1:1 mixture of HRJ-10518 and SP-1045) exhibited higher shear stress, viscosity, elastic modulus and tensile strength than those of the first three types of TPV. Lower tension set and damping factor were also observed in these mixes, indicating greater elasticity. Moreover, the TPVs with phenolic containing cure systems are a two-phase system with smaller vulcanized rubber domains dispersed in the PP matrix. This causes higher interfacial adhesion and interaction between the vulcanized ENR domains and PP matrix. Hence, higher shear stress, shear viscosity, complex viscosity, elastic modulus and tensile strength of the TPVs with phenolic containing cure system were observed. Lower damping factor and tension set values were also a result of the smaller vulcanized rubber domains. It was also found that the ENR/PP TPVs were recyclable. That is, after the 4th reprocess cycle, the TPVs with phenolic containing cure systems showed tensile strength, elongation at break and tension set of approximately 10 MPa, 300% and 20%, respectively.