As-prepared Materials Research Articles

Investigation and development of photocathodes using polyaniline Encapsulated Ti3C2Tx MXene nanosheets for dye-sensitized solar cells.

In the current study, polyaniline (PANI) modified two-dimensional Ti3C2Tx MXene composites (PANI-Ti3C2Tx) are exploited as photocathodes in dye-sensitized solar cells (DSSCs). The study revealed that incorporating PANI into Ti3C2Tx improved the material's electrochemical properties, owing to the presence of amino groups in PANI that enhanced the material's electrical conductivity and thereby facilitated more rapid ion transport. In addition, PANI enhanced the surface wettability of Ti3C2Tx, resulting in an increase in the number of electroactive sites. The presence of PANI molecules in the interlayer and on the surface of Ti3C2Tx was confirmed through X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), and X-ray photoelectron spectroscopy (XPS). Subsequently, electrochemical analysis of the PANI-Ti3C2Tx photocathode or counter electrode (CE) revealed a commendable electrocatalytic activity with the iodide/triiodide electrolyte, a favourable charge transfer kinetics, and a charge transfer resistance as low as platinum. Additionally, at AM 1.5G, the performance of the DSSC constructed using the thermally decomposed Pt-CE was 8.3% when subjected to simulated 1 sun light, whereas the efficiency of the DSSC constructed using the as-prepared composite material was 6.9% under corresponding conditions. PANI-Ti3C2Tx as the photocathode (CE) in a DSSC showed a higher power conversion efficiency (PCE) improvement than PANI CE and Ti3C2Tx CE DSSCs, emphasizing its potent catalytic activity and quick mass transport of electron capability. By capitalizing on the conductivity and electrocatalytic property of the two components, the as-fabricated PANI-Ti3C2Tx photocathode significantly increased the overall PCE of DSSCs. Furthermore, the DSSC utilizing the PANI-Ti3C2Tx CE demonstrated exceptional reproducibility and stability. This underscores its consistently high performance and significant resistance to corrosion in the iodide/triiodide redox electrolyte environment. Overall, these findings show that the PANI-Ti3C2Tx composite has the potential to be a competitive alternative to platinum-based CE materials for the development of DSSCs with exceptional performance.

Morphological and electrocatalytic studies on Ni2+ doped MnWO4 microflowers: A dual mode catalyst for the electrochemical sensor and supercapacitor application

Here, we fabricated nickel-doped manganese tungstate microflowers (N-MW MFs) for electrochemical sensor and supercapacitor applications. N-MW MFs were prepared using the reflux method followed by a calcination process. The doping ratio of nickel varied between 0.3, 0.5, and 0.7 mmol and they were designated as N-MW-0.3 MFs, N-MW-0.5 MFs, and N-MW-0.7 MFs, respectively. The as-prepared materials were analyzed and confirmed by the following physiochemical characterization methods: Powder-XRD, FT-IR, Raman, XPS, FE-SEM, and HR-TEM analysis. N-MW-0.5 MFs modified SPCE exhibited a well-resolved chlorpromazine (CHPMZ) oxidation peak in the CV experiments, which can be attributed to the strong synergistic effect between two different metal ion combinations and the presence of crystal defects. From the optimization result, the N-MW-0.5 MFs/SPCE exhibits a low detection limit of 2 nM and higher sensitivity (0.859 μA μM−1 cm−2) and wide linear ranges (0.01–77.81 μM and 95.81–1230.81 μM). The fabricated CHPMZ sensor was also successfully used for the determination of CHPMZ in water and human blood serum and showed acceptable recovery. In addition, the prepared N-MW-0.5 exhibited an improved specific capacitance of 222.7 F g−1 at a current density of 1 A g−1. Based on the results, we believe that the fabricated N-MW MFs-modified electrode is a potential candidate for CHPMZ sensor and supercapacitor applications.

Cu2Te/CoTe nanoparticles with tuneable bandgaps: Implications for photovoltaic and optoelectronic devices

Herein, we report the structural, optical, and electrochemical response of Cu2Te/CoTe nanoparticles synthesized by the facile microwave synthesis method by varying Cu and Co concentrations. Various characterizations such as Rietveld-refined X-ray diffraction, Raman Spectroscopy, and Transmission electron microscopy analysis infer the two hexagonal phases Cu2Te and CoTe having space group p6/ mmc and P63/ mmc, respectively. The elemental Energy-dispersive X-ray and X-ray photoelectron spectroscopy confirm the composition of all the elements. Field emission scanning electron microscopy images exhibit nanoparticles that remain unaltered even after the essential concentration variation. However, the differential scanning calorimetry study analyses the phase change of the material from room temperature to higher temperatures. Meanwhile, from UV-Vis spectroscopy, the optical band gap increases, and the refractive index value decreases in both the cases, Tauc plot, as well as Kubelka-Munk plot by varying Cu and Co concentrations, which shows well-defined properties that enable the material for various solar cell and optoelectronic applications. In addition, the electrochemical impedance spectroscopy analysis of the as-prepared material reveals small kinetic at high-frequency regions that can be used as the charge transfer of the electrode-electrolyte interface. The tuneable structural, optical, and electrochemical response of the CuCoTe nanomaterial broadens the advanced optoelectronic application prospects.

Eco-friendly synthesized manganese dioxide nanoparticles using Tridax procumbens as potent antimicrobial and dye degrading agent

Manganese dioxide nanoparticles (MnO2 NPs) were synthesized via a typical green synthesis method involving Tridax procumbens (TP) leaf extract extraction and utilization. The as-prepared material was further characterized using various physio-chemical methods to comprehend its structural, morphological, and optical properties. Powder X-ray diffraction (PXRD) reveals a tetragonal system with a space group of I 41/a m d, clearly indicating the presence of phytochemicals (impurity peaks at 25.46° and 54.92° diffraction angles). The calculated crystalline size of the sample was found to be 43 nm. Field Emission Scanning Electron Microscope (FESEM) results confirm the precursors of the as-prepared sample, also revealing the agglomerated structure. Furthermore, deeper morphology and crystallinity of the as-prepared MnO2 NPs have been studied through High-Resolution Transmission Electron Microscope (HR-TEM) images, which affirms the information about calculated d-spacing value (0.328 nm) and confirming crystallinity through Selected Area Electron Diffraction (SAED) image. Absorption studies were conducted on as-prepared samples, which show a characteristic band at 257 nm, affirming the formation of MnO2 NPs. The same was utilized to evaluate the band gap energy (4.46 eV) through the Kubelka-Munk function. To further confirm the calculated particle size and stability of the as-prepared MnO2 NPs, Dynamic Light Scattering (DLS) analysis was conducted, and the results revealed that the particles’ size was 58.72 nm. The prepared samples were subjected to study antimicrobial studies against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacterial species. The inhibition zone of the antibacterial disc soaked with as-prepared MnO2 NPs showed a significant increase compared to the TP leaf extract and commercially available MnO2 NPs. Also, the degradation of the Titan Yellow dye solution was conducted employing UV irradiation, and it was found that the maximum degradation percentage was attained after 120 min of irradiation. Furthermore, the pH effect on %degradation and reusability test were also conducted. The obtained results showed a pinnacle pH point of 4 where the degradation was maximum and found a decent decrement in %degradation after 4th usage. All the acquired results were utilized to study the degradation reaction kinetics, which was found that the present degradation holds good for both 0th and 1st order kinetic equations. Henceforth, the acquired results suggest that the green synthesized MnO2 NPs are potent candidates for antimicrobial and degrading activities.

Structural, optical, photoluminescence and sunlight photocatalytic properties of sprayed NiO-ZnO nanocomposite thin films

In this study, the photocatalytic properties of NiO-ZnO nanocomposite thin films were explored towards the degradation of a pollutant model, methylene blue, when exposed to sunlight. The spray pyrolysis technique was used to synthesize nano-sized pristine ZnO and NiO, as well as NiO-ZnO nanocomposites with different molar ratios (Ni:Zn 1:3, 1:1, 3:1). The as-prepared materials' structural and optical characteristics were investigated using different techniques such as XRD, Raman, EDX, SEM, photoluminescence, and UV–visible spectroscopy. Thewetting propertiesof the samples were evaluated using contact angle measurements. The deposited NiO-ZnO nanocomposites were shown to have higher photocatalytic activity than the individual semiconductors. The enhanced activity of nanocomposites might be due to improved charge separation and the existence of oxygen vacancy, which capture these charges to produce active radicals after interacting with adsorbed oxygen. The inherent correlations between photocatalytic activities and PL intensities were investigated in depth.

Halloysite nanotubes decorated with Co(OH)F nanorods as a novel binary composite for the enhanced electrocatalytic water oxidation

Oxygen evolution reaction is central to several emerging electrochemical energy conversion and storage technologies. This study reports the synthesis, characterization, and OER electrocatalytic performance of binary nanocomposites composed of halloysite nanotubes (HNTs) and Co(OH)F. Five Co(OH)F/HNT with different compositions were fabricated by a facile hydrothermal synthesis. The crystalline phase and microstructure of the as-prepared materials were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The synthesized Co(OH)F (pristine or mixed with HNTs in the nanocomposites) revealed an orthorhombic crystal system with a nanorod morphology. The nanocomposite with ∼19 wt% of Co (designated as Co(OH)F/HNT_3) was found to possess an appreciably improved activity in OER compared to the pristine HNTs, Co(OH)F, and other Co(OH)F/HNT nanocomposites. Co(OH)F/HNT_3 displayed an overpotential of 252 mV (at the current density of 10 mA cm−2), a Tafel slope of 51.1 mV dec−1, and a robust operational performance under harsh alkaline conditions. Furthermore, nitrogen adsorption–desorption isotherms indicated a much higher specific surface area for this nanocomposite than its components. Overall, the versatile synthesis and outstanding catalytic performance of Co(OH)F/HNT_3 make it an auspicious earth-abundant transition metal-based electrocatalyst for OER in an alkaline medium.

Synergetic Effect Of Ternary Mixture Of Nano Silicon Carbide-Polyvinyl Alcohol-Lithium Sulfate On Early Strength Of Cement

T o solve the problems of low compressive strength and unstable sealing capability of traditional hole sealing materials in the early stage of underground coal mines, a new cement-based sealing material was developed in this study by mixing ordinary Portland cement with nanomaterial, water-soluble polymer and lithium salt as additives. The early strength and the microstructure evolution of the as-prepared cement material were investigated with uniaxial compression test, scanning electron microscope (SEM), thermogravimetric analysis and X-ray diffraction (XRD). The results show that the ternary composite material (nano silicon carbide, polyvinyl alcohol and lithium sulfate) can effectively improve the early strength of cement. The 1-day compressive strength increased from 8.56 to 14.21 MPa, pointing out an improvement rate of 66.00%. It can be seen from the SEM images that a large number of fibrous C-S-H crystals and rod-shaped AFt crystals formed in the ternary composite cement sample. The nanosized silicon carbide (SiC) can accelerate the generation of hydration products through forming nucleation sites. As a dispersing agent polyvinyl alcohol (PVA) can effectively prevent the agglomeration of SiC nanoparticles and the formation of cement particle flocculation structure. On the other hand, the lithium cations and the sulfate anions of lithium sulfate could penetrate the hydration film structure and react with the hydration product Ca(OH)2, respectively, which promotes the hydration reaction. The promotion effect of the ternary composite material on the formation of hydration products results in a clearly improved early strength of the new cement-based sealing material.

An electron transfer tuning strategy for the efficient degradation of tetracycline hydrochloride by Fe-N co-doped carbon materials activated with peroxymonosulfate

In order to address the problems of metal leaching and low electron transfer efficiency, the iron (Fe) nitrogen (N) co-doped MOFs derived carbon catalysts presented a promising strategy to activate peroxymonosulfate (PMS) for water purification. In this work, using the MOF-5 as a template and iron phthalocyanine (FePc) and dicyandiamide (DCD) as a source, Fe, N co-doped carbons were prepared through milling and two-step pyrolysis. The catalytic performance and mechanism of the materials on tetracycline hydrochloride (TC) degradation in the PMS activation system (0.1Fe/N-CPMS) was systematically investigated. The results showed that the stable framework structure of MOFs-derived carbon conduced to encapsulate the Fe nanoparticles within the carbon skeleton, and then the xFe/N-C catalyst with hierarchical pore structure and good electrical conductivity was obtained, which significantly improved the TC catalytic performance. Notably, the 0.1Fe/N-C exhibited the greatest degradation performance achieving a degradation rate of 0.6315 min-1, which was approximately five times higher than that of N-C. Moreover, the degradation performance of the 0.1Fe/N-C kept the stability in various interference conditions, and still remained over 80% after three cycles test. Combine with the characterization and DFT calculation, the mechanism of the TC degradation in 0.1Fe/N-CPMS system was revealed by a non-radical process dominated by electron transfer, and the degradation efficiency was greatly improved by the synergistic effect of Fe/N on the as-prepared material. The received findings provide an electron transfer tuning strategy of Fe/N co-doped carbon nanomaterials synthesis for promoting the non-radical degradation pathways in the application of organic pollutants removal.

Unlocking the Potential of Li-Rich Mn-Based Oxides for High-Rate Rechargeable Lithium-Ion Batteries.

Lithium-rich Mn-based oxides have gained significant attention worldwide as potential cathode materials for the next generation of high-energy density lithium-ion batteries. Nonetheless, the inferior rate capability and voltage decay issues present formidable challenges. Here, a Li-rich material equipped with quasi-three-dimensional (quasi-3D)Li-ion diffusion channels is initially synthesized by introducing twin structures with high Li-ion diffusion coefficients into the crystal and constructing a "bridge" between different Li-ion diffusion tunnels. The as-prepared material exhibits monodispersed micron-sized primary particles (MP), delivering a specific capacity of 303mAhg-1 at 0.1 C and an impressive capacity of 253mAhg-1 at 1 C. More importantly, the twin structure also serves as a "breakwater" to inhibit the migration of Mn ions and improve the overall structural stability, leading to cycling stability with 85% capacity retention at 1 Cafter 200 cycles. The proposed strategy of constructing quasi-3Dchannels in the layered Li-rich cathodes will open up new avenues for the research and development of other layered oxide cathodes, with potential applications in industry.

Fabrication of a superhydrophobic-superoleophilic particle material for oil-water separation and oil extraction

Oil-water separation has become a serious issue due to the increasing oily wastewater discharged in the environment and oil spills from time to time. Superhydrophobic and superoleophilic materials are a promising approach in oil-water separation. However, the preparation procedures for these materials are often complex and expensive, and their stability is not robust enough. In this study, superhydrophobic and superoleophilic particles are successfully prepared via a facile and green mixing method. Fluorocarbon resin, CaCO3 and SiO2 are coated on fly-ash cenospheres to form a stable superhydrophobic-superoleophilic surface, which exhibits a water and oil contact angle of 153.3° and 0°, respectively. To our knowledge, we’re unaware of any previous study reporting a superhydrophobic-superoleophilic material prepared in such a convenient way. The as-prepared superhydrophobic material can serve as high-performance filters for separating various oil-water mixtures, with a separation efficiency up to 99.2%. And it can be applied in water-in-oil emulsion separation. Meanwhile, the as-prepared particles are able to extract oils from oil-water mixtures and the oil-extraction capacity is up to 0.56 g/g. Furthermore, the obtained material has a robust stability against various hash conditions and a good recyclability. The simply-prepared superhydrophobic cenospheres are expected to be a promising candidate for application in diverse oil-water separation situations.

F-doped carbon derived from asphalt by mechanochemical approach: More effective toward selective CO2 capture

Porous carbon materials are a preferred choice for CO2 capture and separation owing to unique physical and chemical properties. Here, mechanochemical synthesis of porous carbon (high surface area, up to 1188 m2g−1) and in situ fluorine doping have been accomplished with asphalt as carbon source and Teflon (PTFE) as porogen and fluorine-doped precursors. Ball milling treatment are indispensable for the subsequent carbonization process of asphalt-PTFE mixture. The particle mixing and surface activation in the solid state are promoted by the input of mechanical energy and reaction mixtures are exposed to mechanical force impact. Meanwhile, the micropores and polar functional groups rich in the as-prepared carbon materials both conduce to higher CO2 capture and increase in adsorption energy based on DFT calculation. As evidence, the CO2 uptake capacity reached to 4.1 mmol g−1 for F-C-30# at 273 K, 1 bar. The CO2/N2 selectivity could reach up to 54 under ambient conditions, thereby reflecting a highly competitive CO2-adsorption capacity.

Enhancing energy storage performance in flexible all-solid-state laser-induced graphene-based microsupercapacitors through the addition of carbon black and Prussian blue

In this study, we present an efficient and scalable method for the stepwise modification of polyimide (PI)-based laser-induced graphene using environmentally friendly additives. The as-prepared composite materials were applied as flexible electrodes for high-performance all-solid-state microsupercapacitors (MSCs). The electrochemical deposition of carbon black (CB) microparticles and Prussian blue (PB) inorganic redox dye onto the laser-induced graphene electrode surface significantly enhanced the electrochemical performance of the devices. The areal capacitance of MSCs increased by 116 % after the addition of CB to the electrode composition, 201 % after the modification of the electrode surface with PB, and 325 % after incorporating both CB and PB (CB-PB). The exhibited capacitance values at an applied current density of 0.1 mA·cm−2 are equal to 27.6, 38.5 and 54.4 mF·cm−2 upon incorporating CB, PB and CB-PB, respectively. Furthermore, the use of a PVA/H2SO4 gel electrolyte led to a large stability electrochemical window of 3.0 V, resulting in an energy density as high as 68.1 μWh·cm−2 with a power density of 0.3 mW·cm−2 at 0.10 mA·cm−2. Additionally, the MSCs modified with CB-PB showed an excellent electrochemical stability, retaining over 95.8 % of their initial capacitance after 6000 galvanostatic charge-discharge cycles. Overall, this study presents a facile, convenient, and scalable approach for designing cost-effective and high-performance MSCs with a low-carbon footprint suitable for powering low-energy-consuming electronics.

A facile and green strategy for mass production of dispersive FeCo-rich phosphides@N,P-doped carbon electrocatalysts toward efficient and stable rechargeable Zn-air battery and water splitting

One key step for advancing the widespread practical application of rechargeable metal-air batteries and water electrolysis fundamentally relies on the development of cost-effective multifunctional electrocatalysts toward oxygen and hydrogen-involving reactions. The present work initiates a tofu-derived one-pot strategy for green, facile, and mass production of highly active and stable catalyst toward oxygen reduction/evolution and hydrogen evolution reactions, through the preparation of Fe/Co cross-linked tofu gel and the subsequent pyrolysis. Despite the free use of additional N/P precursors or pore-forming agents, the as-prepared materials comprise highly dispersive FeCo-rich phosphides nanoparticles and porous N,P co-doped carbon network inherited from the tofu skeleton. The resultant catalysts exhibit remarkably enhanced trifunctional activities as compared to the Fe2P and Co2P counterparts, along with better long-term stabilities than the benchmark RuO2 and Pt/C catalysts. Accordingly, the as-assembled Zn-air battery delivers a large power density (174 mW cm−2) with excellent cycle stability (the gap of charge/discharge voltage@10 mA cm−2 increases by 0.01 V after 720 h of operation, vs. 0.16 V of Pt/C-RuO2 based battery after 378 h). Furthermore, the as-constructed alkaline electrolyzer just requires a small voltage of 1.55 V@10 mA cm−2, which outperforms nearly all of those of biomass-derived electrocatalysts ever reported, and that of noble metal catalysts-based electrolyzers (1.72 V@10 mA cm−2 for Pt/C-RuO2), underscoring their bright future toward commercial applications in green energy conversion devices.

Widely improved supercapacitance properties of zirconium‑cobalt ferrite nanoparticles by N-doped graphene oxide as an electrode in supercapacitor

Recently, supercapacitors have garnered considerable attention as promising energy storage devices owing to their unique characteristics. Ferrites are commonly recognized as an innovative category of porous materials that present prominent features, including substantial pore volume, high chemical stability, and large specific surface area, contingent upon the precise selection of components. In this research, we fabricated the zirconium ferrite (ZrFe2O4), cobalt ferrite (CoFe2O4), zirconium cobalt ferrite (ZrCoFe2O4), and nitrogen-doped reduced graphene oxide (NRGO) combination with ZrCoFe2O4 (ZrCoFe2O4/NRGO). ZrCoFe2O4/NRGO nanocomposite is constructed by a co-precipitation route as an electrode material for the application of supercapacitors devices. The formation of samples was specified by several techniques like transmission electron microscopy (TEM), X-ray diffraction (XRD), fourier transformation infrared (FTIR), energy dispersive X-ray (EDX), and field emission scanning electron microscopy (FESEM) spectra. The results of structural characterization show that the pore diameter of NRGO is 80.259 nm, CoFe2O4 is 24.301 nm, ZrFe2O4 is 3.1651 nm, ZrCoFe2O4 is 62.617 nm, and ZrCoFe2O4/NRGO is 21.112 nm. The charge storage mechanism and electrochemical activity of as-prepared materials were appraised using the galvanostatic charge/discharge (GCD), cyclic voltammogram (CV) methods, and electrochemical impedance spectroscopy (EIS) test. The ZrCoFe2O4/NRGO electrode demonstrated superb electrochemical activity with a specific capacitance (SC) of 307 F g−1 at a current density of 1 A g−1. According to the stability examination, it was found that the maintenance of the initial capacity stood at approximately 97 % after 5000 cycles, indicating notably good electrochemical stability whereas shown lowest resistance in electrochemical impedance spectroscopy. A constructed asymmetric supercapacitor device (ASD) that utilized hybrid ZrCoFe2O4/NRGO//NRGO electrodes indicated a SC of 137 F g−1 at 1 A g−1, energy density of 42.7 Wh kg−1, and power density of 618.5 W kg−1. These findings indicate that the ZrCoFe2O4/NRGO//NRGO composite material has the capability to be employed as unique electrode material in supercapacitor applications to produce high-efficiency and reliable energy storage devices.

Tetrahedral coordinated Mn(V) in Ba3V2O8 with varied stoichiometry as thermally stable turquoise to dodger blue inorganic pigments

In this paper, we reported the synthesis of a new family of thermal stable Ba3V2-xMnxO8 blue-green pigment materials based on the [MnO4]3- (V) chromophore. All samples were synthesized by a conventional high-temperature solid state method. Powder X-ray diffraction results showed that the structures of the as-prepared materials were hexagonal crystal system and the space group was R-3m. Infrared and Raman spectra indicated random disorder and structural modification of the pigment. Diffuse reflection spectra were obtained over the range of wavelength 200–1200 nm indicated that the blue-green color of the pigment is caused by optical absorption due to the CT transition in the tetrahedral MnO4 and the d-d transition of Mn5+ in the yellow-red light region. With the increase of temperature, the color of the pigment basically remains unchanged, showing the good thermal stability. Thus, this paper provides a family of new thermal stable blue-green pigment based on tetrahedral Mn(V) coordination with potential applications.

Na2.60Fe1.70(SO4)3 particles embedded in cross-linked graphene oxide networks as high-performance dual-electrode for sodium-ion batteries

Sodium iron sulfate materials have been initially applied to sodium ion batteries (SIBs) owing to their high operating voltage and stable electrochemical properties, yet poor conductivity and low theoretical capacity limit its commercial development. Herein, we first prepared Na2.60Fe1.70(SO4)3@graphene oxide (GO) composite via a facile solid-phase ball milling strategy, which are Na2.60Fe1.70(SO4)3 particles embedded in cross-linked GO networks. For the cathode of SIBs, the active particles in the material are wrapped with cross-linked GO networks that increases the electrolyte penetration and ion transport channels as well as improves electronic conductivity, resulting in a high operating voltage of 3.74 V and excellent cycle stability (retains over 70 % of capacity after 500 cycles at 8 C). Notably, the as-prepared material could exhibit a reversible capacity of 100 mAh g−1 after 100 cycles at 0.2 C as anode for SIBs. Furthermore, the material was first used to assemble symmetric sodium-ion full cell, demonstrating excellent electrochemical performance (achieving 60 mAh g−1 at 0.2 C). The Na2.60Fe1.70(SO4)3 particles wrapped with cross-linked GO networks offer a simple and effective approach to enhance the performance of SIBs, making an important contribution towards their practical industrial application.

Degradation of multiple xanthates using highly efficient visible light-responsive BiOBr-TiO2 composite photocatalysts

BiOBr-TiO2 (BT) composite photocatalysts were synthesized by using a two-step method including hydrothermal synthesis and water-bath precipitation. The microstructural characterization analysis proved that high-crystallinity and high-purity binary BT materials were achieved without by-products. TiO2 nanoparticles with a diameter of approximately 15 nm were decorated on multi-layered BiOBr nanosheets. The results showed that BT had highly-improved adsorption capacity and photocatalytic efficiency in comparison to pristine BiOBr and TiO2. The reaction rate constant of the optimal BT-2 composite photocatalysts for the degradation of 20 mg/L sodium ethyl-xanthate could reach 0.06496 min−1, which was 2.7 and 40.3 times than pure BiOBr and TiO2, respectively. The free radical scavenger test demonstrated that photogenerated holes were the main active species in the photocatalytic degradation reaction process. A possible degradation pathway for SEX molecules was provided through the interaction of visible light and BT-2 photocatalyst. The as-prepared BT materials can be used as efficient photocatalysts to completely degrade various types of xanthates under visible light.

Cu and Ni Co-Doped Porous Si Nanowire Networks as High-Performance Anode Materials for Lithium-Ion Batteries.

Due to its extremely high theoretical mass specific capacity, silicon is considered to be the most promising anode material for lithium-ion batteries (LIBs). However, serious volume expansion and poor conductivity limit its commercial application. Herein, dealloying treatments of spray dryed Al-Si-Cu-Ni particles are performed to obtain a Cu/Ni co-doped Si-based anode material with a porous nanowire network structure. The porous structure enables the material to adapt to the volume changes in the cycle process. Moreover, the density functional theory (DFT) calculations show that the co-doping of Cu and Ni can improve the capture ability towards Li, which can accelerate the electron migration rate of the material. Based on the above advantages, the as-prepared material presents excellent electrochemical performance, delivering a reversible capacity of 1092.4 mAh g-1 after 100 cycles at 100 mA g-1. Even after 500 cycles, it still retains 818.7 mAh g-1 at 500 mA g-1. This study is expected to provide ideas for the preparation and optimization of Si-based anodes with good electrochemical performance.

Chrysanthemum flower-like copper molybdenum oxide decorated graphene oxide nanoribbon composite: A novel positive electrode material for asymmetric supercapacitor devices

This study used hydrothermal followed by ultrasonic methods to generate a composite of CuMoO4-adorned graphene oxide nanoribbons that resembled Chrysanthemum flowers (CuMoO4/GONR). The as-prepared materials were confirmed using a variety of physicochemical methods. Different electrochemical approaches were used to determine the supercapacitor efficiency of at-the-time-fabricated electrodes, including cyclic voltammetry (CV), Galvanostatic charge-discharge tests (GCD), and electrochemical impedance spectroscopy (EIS). The findings demonstrate that compared to pure CuMoO4 and GONR matrixes, CuMoO4/GONR composite deserves dominance, such as more surface area, the occurrence of multiple active sites, improved penetration/diffusion ability, and excellent conductivity. The CuMoO4/GONR composite demonstrated a significant capacitance retention of 89 % at 5 A/g and delivered a comparably high specific capacitance of 865 F/g at 1 A/g. The prepared CuMoO4/GONR//AC asymmetric device showed a 41.7 Wh/kg energy density at 1058 W/kg power density. The obtained results validated CuMoO4/GONR composite as the promising source of electrode material used in supercapacitor devices.

Synthesis and study of carbon nanomaterials through arc discharge technique for efficient adsorption of organic dyes

In this study, we employed the conventional arc discharge technique to synthesise carbon nanomaterials, with a primary focus on optimizing process parameters, specifically gas pressure and arcing voltage. These parameters are explored to enhance both the yield and quality of carbon nanotubes and carbon soot. Three distinct pressure levels (200, 400, and 600 Torr) and voltage settings (30, 35, and 40 V) were systematically investigated. The as-prepared materials underwent comprehensive characterization using a suite of analytical tools, including XRD, FESEM, HRTEM, Raman spectroscopy, and BET analysis. Our research also delved into the practical utility of these carbon nanomaterials by evaluating their dye adsorption capabilities. Specifically, we assessed the efficiency of removing Methyl Orange (MO) and Rhodamine B (RhB) dyes within a 2-hour timeframe. Our findings revealed that carbon nanotubes exhibited moderate performance, achieving 16 % removal efficiency for MO and 60 % for RhB dyes under similar experimental conditions. In contrast, carbon soot demonstrated remarkable efficacy, with removal efficiencies of 53 % for MO and an impressive 82 % for RhB dyes, owing to their high specific surface area. This excellent adsorption performance suggests the potential of these carbon nanomaterials for environmental remediation applications. To further enhance their overall efficiency, we suggest exploring appropriate functionalization techniques in future research endeavours.