Inert Gas Atmosphere Research Articles

Facile synthesis of carbon supported ternary nickel-cobalt-iron nanocatalyst for the hydrodechlorination of 2-chlorophenol

Introduction: Chlorophenols (CPs) have become prevalent in the manufacture of herbicides, fungicides, pesticides, insecticides, pharmaceuticals, and dyes, contributing significantly to water pollution. Addressing this challenge, various treatment methods such as incineration, electrochemistry, photochemistry, biotechnology, and catalytic hydrodechlorination have been explored to reduce toxic chlorophenol contaminants. Hydrodechlorination stands out as an efficient technique for the removal of chlorine atoms. The dispersion of metal nanoparticles on supported materials significantly enhances the catalytic activity by increasing the specific surface area. Among these, carbon-supported nickel-cobalt-iron nanoparticles emerge as promising catalysts for the hydrodechlorination of 2-chlorophenol. Method: This study employs a chemical reduction method at high temperatures under an inert gas atmosphere to synthesize carbon-supported ternary nickel-cobalt-iron nanocatalysts, aiming to detoxify soil and water from pesticide residues. The physicochemical properties of these nanocatalysts were characterized using energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Their catalytic activity was assessed through gas chromatography with a flame ionization detector (FID). Results: The analysis revealed that metallic nanoparticles are uniformly dispersed on the carbon support, with particle sizes ranging from 10 to 60 nm and an average size of 30 nm. The hydrodechlorination (HDC) of 2-chlorophenol (2-CP) achieved satisfactory conversions under various reaction conditions. Conclusion: The carbon-supported nickel-cobalt-iron nanoparticles demonstrated effective catalytic activity for the hydrodechlorination of 2-chlorophenol, highlighting their potential for application in the treatment of chloroorganic contaminations in the future.

Facile SERS substrates from Ag nanostructures chemically synthesized on glass surfaces

A quick one-step fabrication of efficient SERS substrates by a modified approach based on a silver-mirror reaction (using Tollens’ reagent) is reported. Commercially available microscope slides or cover glass (coverslips) were used as-received, without special surface treatment. In contrast to the commonly used two-step process, the composition of the Tollens reagent was modified to use a single-step process. The obtained rather homogeneous films of densely packed nanoislands are promising for application as substrates for Surface-Enhanced Raman Scattering (SERS), as demonstrated by several different kinds of molecules as analytes. In particular, the achieved level of detection of a standard dye analyte, down to 10-14 M of Rhodamine 6G, is in the range of best values reported in the literature. Low concentrations of some biomolecules are also detected, such as lysozyme (10-4 M), adenine (10-4 M), and salicylic acid (10-5 M). For some analytes, stronger SERS was observed in the drop, and for others after the solvent was dried. The possible reasons for this effect are described. By applying thermal annealing in the inert gas atmosphere, the Ag film morphology can be partially converted into a coral-like 3D structure that may be advantageous for the localization of the analyte in the “hot spots” and allow additional spectral tunability of the plasmon resonance.

Collisional broadening and shift of the hyperfine lines for complex atomic systems in atmosphere of the buffer inert gases

An effective approach to determination of the collisional hyperfine lines shift and broadening in a buffer gas medium is presented and based on the generalized kinetic theory of spectral lines, the exchange perturbation theory and relativistic gauge-invariant perturbation theory with the optimized model potential approximation for computing the optimized basises of the relativistic wave functions.The results of calculating the shift and broadening of the hyperfine structure spectral lines due to collisions for complex atoms (here thallium is considered) in an atmosphere of inert gases (Kr, Xe) are presented and compared with other available alternative theoretical and experimental data. It is shown that the ratio of an adiabaticbroadening to a collisional shift for the pair of Tl–Kr (Га/р)/ fр is ~1/75 and for the pair of Tl- Xe(Га/р)/fр ~1/60.These estimates testify to a violation of well-known Foley relationship, which is, as a rule, inviolable in the standard atomic spectroscopy.

Functionalized, bio-derived carbon-aerogel/Li4Ti5O12 composites as anode materials for Li-ion batteries

In this work we investigate the electrochemical behavior of bio-derived carbon-aerogel/Li4Ti5O12 composites (CAG/LTO) in Li-ion half cells. The studied CAG/LTO samples were successfully prepared through the gelatinization process of potato starch precursor with pristine LTO material, followed by controlled pyrolysis in an inert gas atmosphere. The obtained composites were examined by elemental analysis (EA), X-ray diffraction (XRD), N2-adsorption/desorption (N2-sorption), scanning and transmission electron microscopy (SEM, TEM), galvanostatic charge/discharge tests (GCDT), extensive cycling (LT-GCDT) and cyclic voltammetry (CV) methods. The results show, that carbon aerogel compressive matrix significantly improved the electrical conductivity of LTO anode material and was effective only in its composite form. The best electrochemical parameters and overall performance was achieved by 16% CAG/LTO composite. After extensive cycling (1016 charge/discharge cycles under 5 C), its discharge capacity was equal to 209 mAh/g, achieving the capacity retention of 106%.

Rapid synthesis of nanomaterials by solvent-free laser irradiation for energy storage and conversion

Nanomaterials synthesized through laser irradiation have numerous applications in the field of energy storage and conversion. Conventional methods for fabricating nanomaterials often involve extended reaction times, making them susceptible to issues such as reproducibility, impurities, and inhomogeneity. To address these issues, a novel strategy of synthesizing nanomaterials via solvent-free laser irradiation in the gas phase is proposed as a potential solution. This innovative strategy offers ultrafast heating and cooling processes compared to conventional time-consuming methods, resulting in the formation of homogeneous nanosystems within femto- to nanosecond timeframes. The focused laser beam induces rapid photothermal and photochemical effects in either air or an inert gas atmosphere, enabling the rapid production of nanomaterials with precise control over geometry, chemistry, crystallinity, and defect density by adjusting processing conditions and sintering mediums. This review provides insights into the rapid solvent-free laser-assisted synthesis of nanomaterials using natural carbon-based materials, polymers, metal–organic frameworks, and inorganic species in both air and inert atmospheres. The introduction of photo-irradiation across a wide range of precursors facilitates phase transitions and surface functionalization in the resulting nanoproducts. We also discuss the effects of altering laser wavelengths, pulse widths, fluences, and repetition rates on both surface and bulk properties of the final products. Finally, we explore the applications of laser-induced nanomaterials in areas such as rechargeable batteries, supercapacitors, solar cells, and catalysis.

Ring-Opening of 1,3-Imidazole Based Mesoionic Carbenes (iMICs) and Ring-Closing Clicks: Facile Access to iMIC-Compounds.

Herein, ring-opening of mesoionic carbenes (iMICs) (iMIC=[ArC{N(Dipp)}2 C(SiMe3 )C:) (Dipp=2,6-iPr2 C6 H3 , Ar=Ph, 4-Me2 NC6 H4 or 4-PhC6 H4 ) based on an 1,3-imidazole scaffold to yield N-ethynylformimidamide (eFIM) derivatives as crystalline solids (eFIM={(Dipp)N=C(Ar)N(Dipp)}C≡CSiMe3 ) is reported. eFIMs are thermally stable under inert gas atmosphere and show moderate air stability (t1/2= 3 h for Ar=Ph). eFIMs are excellent surrogates of iMICs, which generally have a limited shelf-life, and readily undergo ring-closing click reactions with a variety of main-group as well as transition metal Lewis acids to form hitherto challenging iMIC-compounds in good to excellent yields. In addition to the relevance of eFIMs in the synthesis of iMIC-compounds, quantification of the stereoelectronic properties of a representative iMIC (Ar=Ph) by experimental and theoretical methods suggests remarkably σ-donor property and steric profile of these new ligand sets.

Pyrolysis of Municipal Plastic Waste to Produce Alternate Fuel

This research concentrates on the pyrolysis of municipal plastic waste (MPW) to produce an alternate fuel and its thermal comparison with petrol and diesel. It is a viable response to the growing problem of plastic waste disposal. Fuels made from petroleum and plastics contain carbon and hydrogen and are classified as hydrocarbons. Plastics are made up of fossil fuel-based chemicals such as natural gas or crude oil. It is non-biodegradable waste, mainly consisting of approx 15% of total Municipal Solid Waste (MSW). Plastics are pivotal in today's world and are excessively used in households, industry and other fields due to their lightweight, durability, flexibility and inexpensive ability to produce. The need for plastics is expanding every day, posing a significant danger to the climate.The pyrolysis process is a waste-to-energy technological option for producing alternative fuels to replace fossil fuels. It is a thermochemical decomposition of organic material at high temperatures without oxygen or an inert gas atmosphere. Municipal Plastic Waste is depolymerized, pyrolyzed, catalytically cracked, and fractionally distilled to produce various value-added petroleum-derived fuels via pyrolysis which can be used to replace low diesel oils. The pyrolysis method has the benefit of being able to handle unsorted polymers. The material's pretreatment is simple. Plastics must be sorted, dried, and shredded. Pyrolysis, instead of incineration, doesn't emit harmful or hazardous gases. Transforming municipal plastic waste into energy has significant environmental, climatic, and economic implications.

A Crucial Step Toward Carbon Neutrality in Pyrometallurgical Reduction of Nickel Slag

This study aims at recovering valuable metals from nickel slag by employing pyrometallurgical techniques. A large amount of slag is generated during the nickel matte smelting. Nickel slag contains valuable elements such as copper, nickel, and cobalt, which can be recovered. Disposal of this slag results in loss of resources and may cause pollution of the environment. It is important to retrieve these metals for environmental and economic reasons. In this study, the slag was reacted with non-fossil reducing agents (biochar) which were produced from hydrolysis lignin and black pellet biomass by pyrolysis at 600 and 1200 °C, and with metallurgical coke for comparison. The reduction experiments were done at 1400 °C for 15, 30, and 60 min under inert gas atmosphere. The samples were quickly quenched and analyzed with Electron Probe X-ray Microanalysis. The results showed that the use of biochar resulted in faster reaction kinetics in the reduction process compared to coke. Moreover, thermodynamic modeling was also performed using Factsage to simulate equilibria with different amounts of biochar. The metal-to-slag distribution coefficient calculated from the results of thermodynamic modeling was consistent with experimental results.Graphical

Air Tolerant Cadiot-Chodkiewicz and Sonogashira Cross-Couplings.

Cadiot-Chodkiewicz cross-couplings generate an unsymmetric buta-1,3-diyne by way of a Cu(I)-catalyzed coupling between a terminal alkyne and a 1-haloalkyne. Despite their widespread use, Cadiot-Chodkiewicz reactions are plagued by the generation of symmetric buta-1,3-diyne side products, formed through competing: (a) formal reductive homo-coupling of the 1-haloalkyne and (b) oxidative (Glaser-Hay/Eglinton) homo-coupling of the terminal alkyne. To overcome this issue, a large excess of one of the two reacting alkynes is commonly deployed, and difficult separations of cross- and homo-coupled products are often encountered. Here, we demonstrate that the use of ascorbate as a reductant leads to a suppression of these unwanted side reactions, hence permitting excellent yields with a roughly stoichiometric ratio of reactants. The procedure also avoids an inert gas atmosphere and uses a sustainable solvent. A similar approach is effective for cross-couplings involving a Pd(0)/Pd(II) catalytic cycle, with air tolerant Sonogashira couplings also established.

Thermo-kinetic Study of Genetically Different Carbon-Source Materials.

A nonisothermal thermogravimetric analysis (TGA) technique was applied to determine the devolatilization kinetic parameters of completely different genesis samples of four groups: coal, biomass, lignite, and petcoke. The physical and chemical characteristics were determined using the proximate and ultimate analysis and the ash composition profile using the X-ray fluorescence method. Heating rates of 10, 15, and 20 °C/min were used in the temperature range of 25-1000 °C during the slow pyrolysis under an inert gas atmosphere. A widely used and proposed first-order Coats-Redfern kinetic model was applied, which showed the highest values of activation energies (Ea) for the petcoke sample from 57.17 to 67.58 kJ/mol at three different heating rates, while the lignite sample represented the lowest Ea values between 12.84 and 16.03 kJ/mol. The thermo-kinetic behavior was explained based on the catalytic effect of the ash composition profile, morphology, and structure of the substances determined using different analytical techniques. For the TGA process, the application of scanning electron microscopy, Fourier-transform infrared spectroscopy, etc., for the physiochemical analysis of the four genetically different carbon-source materials represented the novelty of the present work.

Nanotitania supported ruthenium(0) nanoparticles as active catalyst for releasing hydrogen from dimethylamine borane

We reports the ex situ preparation of nanotitania supported ruthenium(0) nanoparticles (NPs) and their catalytic testing in dehydrogenation of dimethylamine borane (DMAB) in toluene solvent. Ru0/TiO2 NPs are prepared following a 2-step process: Ru3+ ions are first impregnated from the aqueous solution on titania nanopowder and then, reduced by aqueous solution of sodium borohydride. The prepared Ru0/TiO2 NPs are dried, bottled under inert N2 gas atmosphere, and used for characterization by XRD (X-ray powder diffraction), TEM (transmission electron microscopy), ICP-OES (inductively coupled plasma optical emission spectroscopy) and XPS (X-ray photoelectron spectroscopy). Ru0/TiO2 NPs with various Ru loadings are tested as catalysts in hydrogen generation from DMAB and the Ru0/TiO2 (0.48% wt. Ru) with an average diameter of 6.7 ± 1.3 nm is found to have the highest initial turnover frequency value of 1700 h−1 for the release of 1.0 mol H2 per mole of DMAB at 60 °C. Results of the recyclability test indicate quite high durability of Ru0/TiO2 NPs in dehydrogenation of DMAB.

Understanding the Thermal Degradation Mechanism of High-Temperature-Resistant Phthalonitrile Foam at Macroscopic and Molecular Levels.

Polymer foam, a special form of polymer, usually demonstrates some unexpected properties that rarely prevail in the bulky polymer. Studying the thermal degradation behavior of a specific polymer foam is important for its rational design, quick identification, objective evaluation, and industrial application. The present study aimed to discover the thermal degradation mechanism of high-temperature-resistant phthalonitrile (PN) foam under an inert gas atmosphere. The macroscopic thermal decomposition of PN foam was carried out at the cost of size/weight loss, resulting in an increasing number of open cells with pyrolyzation debris. Using the TGA/DTG/FTIR/MS technique, it was found that PN foam involves a three-stage thermal degradation mechanism: (I) releasing gases such as H2O, CO2, and NH3 generated from azo-containing intermediate decomposition and these trapped in the closed cells during the foaming process; (II) backbone decomposition from C-N, C-O, and C-C cleavage in the PN aliphatic chain with the generation of H2O, CO2, NH3, CO, CH4, RNH2, HCN, and aromatic gases; and (III) carbonization into a final N-hybrid graphite. The thermal degradation of PN foam was different from that of bulky PN resin. During the entire pyrolysis of PN foam, there was a gas superposition phenomenon since the release of the decomposition volatile was retarded by the closed cells in the PN foam. This research will contribute to the general understanding of the thermal degradation behavior of PN foam at the macroscopic and molecular levels and provide a reference for the identification, determination, and design of PN material.

Capturing Nano‐Scale Inhomogeneity of the Electrode Electrolyte Interface in Sodium‐Ion Batteries Through Tip‐Enhanced Raman Spectroscopy

AbstractA prime challenge in the development of new battery chemistries is the fundamental understanding of the generation of the electrode–electrolyte interface (EEI) and its evolution upon cycling. Tip‐enhanced Raman spectroscopy (TERS) under an inert gas atmosphere is employed to study the chemical components of the anode/cathode electrolyte interface in a sodium‐ion battery. After the first cycle, TERS reveals that the EEI mostly consists of organic carbonate/dicarbonate, oligoethylene oxides, α,β‐unsaturated vinyl ketones/acetates, and inorganic species ClO4−, ClO3−, and Na2CO3. Whereas after 5× cycling, the EEI composition has evolved to contain long chain monodentate or bridging/bidentate carboxylates and alkoxides. The TERS map reveals the nano‐scale heterogeneity present in the EEI layers and elucidates a multilayered nano‐mosaic coating structure. The sheer volume of Raman signature present in the TERS signal can completely unravel the mysteries regarding the chemical composition and may shed light to the physicochemical behavior of the EEI.

Investigating the Production Atmosphere for Sulfide-Based Electrolyte Layers Regarding Occupational Health and Safety

In all-solid-state battery (ASSB) research, the importance of sulfide electrolytes is steadily increasing. However, several challenges arise concerning the future mass production of this class of electrolytes. Among others, the high reactivity with atmospheric moisture forming toxic and corrosive hydrogen sulfide (H2S) is a major issue. On a production scale, excessive exposure to H2S leads to serious damage of production workers’ health, so additional occupational health and safety measures are required. This paper investigates the environmental conditions for the commercial fabrication of slurry-based sulfide solid electrolyte layers made of Li3PS4 (LPS) and Li10GeP2S12 (LGPS) for ASSBs. First, the identification of sequential production steps and processing stages in electrolyte layer production is carried out. An experimental setup is used to determine the H2S release of intermediates under different atmospheric conditions in the production chain, representative for the production steps. The H2S release rates obtained on a laboratory scale are then scaled up to mass production dimensions and compared to occupational health and safety limits for protection against H2S. It is shown that, under the assumptions made for the production of a slurry-based electrolyte layer with LPS or LGPS, a dry room with a dew point of τ=−40 ∘C and an air exchange rate of AER=30 1h is sufficient to protect production workers from health hazards caused by H2S. However, the synthesis of electrolytes requires an inert gas atmosphere, as the H2S release rates are much higher compared to layer production.

Effect of blending duration on physical, mechanical and tribological behavior of aluminum matrix composites: An experimental analysis

Aluminum matrix composites exhibit a vibrant role in the present research and scientific world due to their astonishing features compared to other conventional materials. Among the various techniques available for processing these composites, powder metallurgy (P/M) is considered one of the prominent techniques. This is because of its identical dispersal of the fillers, near net shape samples, etc. wherein blending is the most imperative step of the process. To accomplish efficient blending of the phases for composite preparation, ball milling is found to be suitable. In this paper, aluminum matrix composites filled with 20 wt% novel reinforcement (extracted from Aegle marmelos) is synthesized via the P/M technique by varying the blending duration from 60 to 240 min to study its effect on the behavior of composites. The mixing of the constituents is carried out at 300 rpm with a ball-to-powder ratio of 10:1 in ball milling. The blended powders were then compacted and sintered in an inert gas atmosphere for consolidation. The hardness, density, and wear tests were conducted to characterize the developed composite specimens. The microstructural characterization was carried out using an optical microscope and SEM, and the elemental composition of the synthesized composite was studied using EDS techniques. The hardness and density were found to have a growing influence up to a ball milling duration of 180 min and beyond this time there is found to be a decrement in the characteristics of the composites. This is due to the damage of the reinforcements observed during lengthier ball milling duration. The wear behavior of the fabricated specimens followed the same trend. Further, grey relational analysis was adopted in this study to determine the degree of relationship between the blending duration and the composites’ behavioral performance.

Iridium Based Selective Emitters for Thermophotovoltaic Applications.

The long-term operation of refractory-metal-based metamaterials is crucial for applications such as thermophotovoltaics. The metamaterials based on refractory metals like W, Mo, Ta, Nb and Re fail primarily by oxidation. Here we propose the use of the noble metal Ir as an alternative to refractory metals, stable to oxidation and having optical properties comparable to gold. We demonstrate the thermal endurance of Ir in a 3-layer-system, consisting of HfO2 /Ir/HfO2 , by performing annealing experiments up to 1240°C in a pressure range from 2 × 10-6 mbar to 1bar. The Ir layer shows no oxidation in vacuum and inert gas atmosphere. At temperatures above 1100°C, the Ir layer starts to agglomerate due to the degradation of the confining HfO2 layers. Alternative dielectric layers are required to further increase the application temperature. An in-situ x-ray diffraction experimental comparison between 1D multilayered Ir/HfO2 and W/HfO2 selective emitters annealed at 1000°C, 2 × 10-6 mbar over 100h confirms oxidation stability of Ir while W multilayers gradually disappear. The results of this work show that metamaterials based on oxidizing refractory metals, such as tungsten, are not long-term stable even at 1000°C. The oxidation resistance of Ir can be leveraged for refractory plasmonic metamaterials, such as selective emitters in thermophotovoltaic systems with strong suppression of long wavelength radiation. This article is protected by copyright. All rights reserved.

ELECTROCHEMICAL SYNTHESIS OF INTERMETALLIC U–Ga AND U–Cd COMPOUNDS IN MOLTEN LiCl–KCl–CsCl EUTECTIC

The processes of cathodic reduction of U(III) ions to metal in a low–melting LiCl–KCl–CsCl eutectic at the temperature range 650–850 K on tungsten, gallium and cadmium electrodes in an inert gas atmosphere have been studied by non-stationary and stationary electrochemical methods. Reagents without contain impurities of moisture, oxygen and their compounds were used in the experiments. All major operations were performed in a dry glove box. The following methods were used to analyze the electrochemical processes: cyclic voltammetry, square-wave voltammetry and potentiometry at zero current. On cyclic voltammogram of the molten LiCl–KCl–CsCl–UCl3 solution on an inert tungsten electrode, one cathode current peak corresponding to the deposition of metallic uranium and one anode current peak associated with its dissolution were recorded. It was found that the potential of the cathode peak was shifted to a region of more negative values with an increase of the scan rate. The value of the cathode peak current was directly proportional vs. the square root of the polarization rate, but this dependence does not pass through the origin. Consequently, the system of U(III)/U(0) couple was irreversible and proceeds in one stage. It was found that on square-wave voltammograms in the studied “electrochemical window” the deposition of uranium on liquid reactive gallium and cadmium electrodes was carried out at more positive values than on inert tungsten electrode. It was established that this potential shift was associated with the formation of intermetallic compounds of uranium with the material of reactive electrodes. The values of the alloy formation potentials were determined. For identification of the composition of cathode deposits, potentiostatic electrolysis was performed. By X–ray diffraction analysis, it was found that the formation of the intermetallic compounds Ga3U and Ga2U occurs on the gallium reactive electrode, and Cd11U occurs on the cadmium one. The conditions of their formation during the electrolysis of molten LiCl–KCl–CsCl–UCl3 solutions were established. The reaction of the electrochemical extraction of uranium from molten LiCl–KCl–CsCl–UCl3 electrolyte was investigated on liquid reactive electrodes at different duration of electrolysis. It was found that the electrochemical extraction of uranium exceeds 97% on both Ga and Cd electrodes.

Settings of a monolithic piezoelectric filter on bulk acoustic waves by ion-beam etching

The process of tuning of the piezoelectric filter consists in lowering the frequencies of the resonators as a result of removing the electrode layer by means of ion-beam etching (IBE) in an inert gas atmosphere. It is necessary to control frequencies of the first and second resonators, as well as the frequency spacing (distance between frequencies of the upper and lower resonances of the piezo system), dynamic impedance of partial resonators and insertion attenuation. We present the results of using ion-beam etching in tuning monolithic piezoelectric filters on volumetric acoustic waves. It is shown that tuning should be performed using frequencies of the upper and lower resonances of the piezo system under control of the insertion attenuation. It is also necessary to exclude the control operations for the frequencies of the first and second resonators. The optimum parameters of ion-beam etching electrodes of the resonators are determined: working pressure — 1.33 × 10–5 Pa, working gas flow — 1.75 m3 · Pa/sec, ion beam energy — 1 keV, ion current density — 6 mA/cm2. Moreover, the dependence of the insertion damping and dynamic resistance on the frequency of the resonator was revealed. Characteristics of the obtained monolithic quartz filter are presented: nominal frequency — 21400.681 MHz, bandwidth by –3 dB — 32.66 kHz, insertion loss 0.5 dB. The obtained results can be used when tuning sections with smaller electrodes for filters at higher frequencies.

Direct generation of Zn metal using laser-induced ZnS to eradicate carbon emissions from electrolysis Zn production

In response to the goal of net-zero emissions proposed by Intergovernmental Panel on Climate Change, Chinese government has pledged that carbon emissions will peak by 2030, and achieve carbon neutrality by 2060. However, the high carbon energy structure of traditional industries has aggravated environmental problems, such as greenhouse effect and air pollution. The goal of carbon neutrality will be difficult to achieve without the development of disruptive theories and technologies. The electrolytic zinc industry requires high-temperature roasting at ∼1000 °C, generating large amounts of greenhouse gases and SO2. High concentrations of sulfuric acid (200 g/L) are subsequently used for electrolysis, and each ton of zinc produced generates 50 kg of anode slime with lead content of up to 16%, as well as 0.35 m3 of wastewater containing zinc and lead. To solve these problems, an optical metallurgy method is proposed in this study. The proposed method uses laser-induced photoreduction to decompose ZnS and reduce metal ions to metal. Results indicate that Zn0 and S8 can be detected on the surface of ZnS at a specific wavelength and laser fluence. The generation mechanism of Zn0 is such that laser induces an electronic transition that breaks ionic bond in ZnS, resulting in its decomposition and photoreduction to Zn0 under an inert argon gas atmosphere. This method does not reduce other metals in the mineral since it does not use high-temperature roasting, providing a new way of producing high-purity metal without greenhouse gas emissions and heavy metal pollution caused by traditional zinc electrolysis.

Micro-Structure and Dielectric Properties of Ti3C2Tx MXene after Annealing Treatment under Inert Gases

At present, the rapid development of electronic devices such as batteries, sensors, capacitors and so on is creating a huge demand for lightweight materials with a designed structure and function. Ti3C2Tx MXene, a lightweight two-dimensional (2D) nanomaterial with excellent electronic properties, has been favored in this field. In this work, Ti3C2Tx MXene was annealed under an inert gas (N2, Ar and CO2) atmosphere to design the crystal structure and interface of the nanosheets, and then the modified nanosheets with specific changes in dielectric properties were obtained. Among them, the key temperature points (100 °C, 300 °C, 500 °C and 800 °C) in the thermogravimetric (TG) test under an air atmosphere were used as the annealing temperature. When annealing under an air atmosphere, with the increase in temperature, the Ti layer gradually oxidized and evaporated, and the original two-dimensional structure was partly destroyed with some of the C atoms reacting with O2 to form CO2. In the inert gas atmosphere, however, the 2D structure is preserved, except that the surface end groups and layer spacing are changed. In addition, some N element doping was introduced into the nanosheets after N2 atmosphere treatment, which changed the original lattice structure. After the Ar atmosphere treatment, some Ti atoms on the surface were oxidized in situ to form TiO2 grains with different crystal forms, which increased the interfacial area. The C-TiO2 structure of the nanosheets was more complete after treatment with the CO2 atmosphere. All the nanosheets after heat treatment with an inert gas atmosphere retained the characteristic morphology of 2D materials, and different changes in the micro-structure caused changes in dielectric properties, thereby meeting the needs of 2D nanomaterials Ti3C2Tx MXene in different scenarios.