Advances in Natural Sciences: Nanoscience and Nanotechnology

Some aspects of the thermodynamics and mechanics of solid surfaces, in particular with respect to surface stress and surface energy, are reviewed. The purpose is to enlighten the deep differences between these two physical quantities. We consider successively the case of atomic flat surfaces and the case of vicinal surfaces characterized by surface stress discontinuities. Finally, experimental examples, concerning Si surfaces, are described.

The authors report the synthesis of Fe₃O₄ nanoparticles by wet chemical reduction technique at ambient temperature and its characterization. Ferric chloride hexa-hydrate (FeCl₃ · 6H₂O) and sodium boro-hydrate (NaBH₄) were used for synthesis of Fe₃O₄ nanoparticles at ambient temperature. The elemental composition of the synthesized Fe₃O₄ nanoparticles was determined by energy dispersive analysis of x-rays technique. The x-ray diffraction (XRD) technique was used for structural characterization of the nanoparticles. The crystallite size of the nanoparticles was determined using XRD data employing Scherrer’s formula and Hall–Williamson’s plot. Surface morphology of as-synthesized Fe₃O₄ nanoparticles was studied by scanning electron microscopy. High resolution transmission electron microscopy analysis of the as-synthesized Fe₃O₄ nanoparticles showed narrow range of particles size distribution. The optical absorption of the synthesized Fe₃O₄ nanoparticles was studied by UV–vis–NIR spectroscopy. The as-synthesized nanoparticles were analyzed by Fourier transform infrared spectroscopy technique for absorption band study in the infrared region. The magnetic properties of the as-synthesized Fe₃O₄ nanoparticles were evaluated by vibrating sample magnetometer technique. The thermal stability of the as-synthesized Fe₃O₄ nanoparticles was studied by thermogravimetric technique. The obtained results are elaborated and discussed in details in this paper.

In this study UiO-66 and UiO-66-NH₂ were synthesized by solvothermal method. The effect of preparation conditions on the quality of UiO-66-NH₂ was studied. The obtained material has been characterized by x-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimatric analysis (TGA), scanning electron microscopy (SEM) and nitrogen physisorption measurements (BET). The CO₂ and CH₄ physisorption measurements were carried out using a high pressure volumetric analyzer (Micromeritics HPVA—100). The results showed that the UiO-66-NH₂ of ball shape crystalline had been obtained and characterized by high surface area (BET) up to 876 m² g⁻¹, specific volume 0.379 cm³ g⁻¹, pore radius 9.5 Å and thermal stability up to 673 K, respectively. The experiments indicated that in comparison with UiO-66 the addition of NH₂ is able to increase the CO₂ and CH₄ storage capacity at 1 bar and 303 K twice from 28.43 cm³ g⁻¹ up to 52 cm³ g⁻¹ and from 6.68 cm³ g⁻¹ to 11.1 cm³ g⁻¹, respectively.

In recent years the outbreak of re-emerging and emerging infectious diseases has been a significant burden on global economies and public health. The growth of population and urbanization along with poor water supply and environmental hygiene are the main reasons for the increase in outbreak of infectious pathogens. Transmission of infectious pathogens to the community has caused outbreaks of diseases such as influenza (A/H₅N₁), diarrhea (Escherichia coli), cholera (Vibrio cholera), etc throughout the world. The comprehensive treatments of environments containing infectious pathogens using advanced disinfectant nanomaterials have been proposed for prevention of the outbreaks. Among these nanomaterials, silver nanoparticles (Ag-NPs) with unique properties of high antimicrobial activity have attracted much interest from scientists and technologists to develop nanosilver-based disinfectant products. This article aims to review the synthesis routes and antimicrobial effects of Ag-NPs against various pathogens including bacteria, fungi and virus. Toxicology considerations of Ag-NPs to humans and ecology are discussed in detail. Some current applications of Ag-NPs in water-, air- and surface- disinfection are described. Finally, future prospects of Ag-NPs for treatment and prevention of currently emerging infections are discussed.

In this work we have demonstrated a powerful disinfectant ability of colloidal silver nanoparticles (NPs) for the prevention of gastrointestinal bacterial infections. The silver NPs colloid was synthesized by a UV-enhanced chemical precipitation. Two gastrointestinal bacterial strains of Escherichia coli (ATCC 43888-O157:k-:H7) and Vibrio cholerae (O1) were used to verify the antibacterial activity of the as-prepared silver NPs colloid by means of surface disinfection assay in agar plates and turbidity assay in liquid media. Transmission electron microscopy was also employed to analyze the ultrastructural changes of bacterial cells caused by silver NPs. Noticeably, our silver NPs colloid displayed a highly effective bactericidal effect against two tested gastrointestinal bacterial strains at a silver concentration as low as ∼3 mg l⁻¹. More importantly, the silver NPs colloid showed an enhancement of antibacterial activity and long-lasting disinfectant effect as compared to conventional chloramin B (5%) disinfection agent. These advantages of the as-prepared colloidal silver NPs make them very promising for environmental treatments contaminated with gastrointestinal bacteria and other infectious pathogens. Moreover, the powerful disinfectant activity of silver-containing materials can also help in controlling and preventing further outbreak of diseases.

Direct wafer bonding processes are being increasingly used to achieve innovative stacking structures. Many of them have already been implemented in industrial applications. This article looks at direct bonding mechanisms, processes developed recently and trends. Homogeneous and heterogeneous bonded structures have been successfully achieved with various materials. Active, insulating or conductive materials have been widely investigated. This article gives an overview of Si and ^SiO₂ direct wafer bonding processes and mechanisms, silicon-on-insulator type bonding, diverse material stacking and the transfer of devices. Direct bonding clearly enables the emergence and development of new applications, such as for microelectronics, microtechnologies, sensors, MEMs, optical devices, biotechnologies and 3D integration.

In this study we report on the synthesis of silver nanoparticles (AgNPs) from the leaf extracts of Moringa oleifera using sunlight irradiation as primary source of energy, and its antimicrobial potential. Silver nanoparticle formation was confirmed by surface plasmon resonance at 450 nm and 440 nm, respectively for both fresh and freeze-dried leaf samples. Crystanality of AgNPs was confirmed by transmission electron microscopy, scanning electron microscopy with energy dispersive x-ray spectroscopy and Fourier transform infrared (FTIR) spectroscopy analysis. FTIR spectroscopic analysis suggested that flavones, terpenoids and polysaccharides predominate and are primarily responsible for the reduction and subsequent capping of AgNPs. X-ray diffraction analysis also demonstrated that the size range of AgNPs from both samples exhibited average diameters of 9 and 11 nm, respectively. Silver nanoparticles showed antimicrobial activity on both bacterial and fungal strains. The biosynthesised nanoparticle preparations from M. oleifera leaf extracts exhibit potential for application as broad-spectrum antimicrobial agents.

Copper nanoparticles, due to their interesting properties, low cost preparation and many potential applications in catalysis, cooling fluid or conductive inks, have attracted a lot of interest in recent years. In this study, copper nanoparticles were synthesized through the chemical reduction of copper sulfate with sodium borohydride in water without inert gas protection. In our synthesis route, ascorbic acid (natural vitamin C) was employed as a protective agent to prevent the nascent Cu nanoparticles from oxidation during the synthesis process and in storage. Polyethylene glycol (PEG) was added and worked both as a size controller and as a capping agent. Cu nanoparticles were characterized by Fourier transform infrared (FT-IR) spectroscopy to investigate the coordination between Cu nanoparticles and PEG. Transmission electron microscopy (TEM) and UV–vis spectrometry contributed to the analysis of size and optical properties of the nanoparticles, respectively. The average crystal sizes of the particles at room temperature were less than 10 nm. It was observed that the surface plasmon resonance phenomenon can be controlled during synthesis by varying the reaction time, pH, and relative ratio of copper sulfate to the surfactant. The surface plasmon resonance peak shifts from 561 to 572 nm, while the apparent color changes from red to black, which is partly related to the change in particle size. Upon oxidation, the color of the solution changes from red to violet and ultimately a blue solution appears.

The present article is a review of research works on promising applications of graphene and graphene-based nanostructures. It contains five main scientific subjects. The first one is the research on graphene-based transparent and flexible conductive films for displays and electrodes: efficient method ensuring uniform and controllable deposition of reduced graphene oxide thin films over large areas, large-scale pattern growth of graphene films for stretchble transparent electrodes, utilization of graphene-based transparent conducting films and graphene oxide-based ones in many photonic and optoelectronic devices and equipments such as the window electrodes of inorganic, organic and dye-sensitized solar cells, organic light-emitting diodes, light-emitting electrochemical cells, touch screens, flexible smart windows, graphene-based saturated absorbers in laser cavities for ultrafast generations, graphene-based flexible, transparent heaters in automobile defogging/deicing systems, heatable smart windows, graphene electrodes for high-performance organic field-effect transistors, flexible and transparent acoustic actuators and nanogenerators etc. The second scientific subject is the research on conductive inks for printed electronics to revolutionize the electronic industry by producing cost-effective electronic circuits and sensors in very large quantities: preparing high mobility printable semiconductors, low sintering temperature conducting inks, graphene-based ink by liquid phase exfoliation of graphite in organic solutions, and developing inkjet printing technique for mass production of high-quality graphene patterns with high resolution and for fabricating a variety of good-performance electronic devices, including transparent conductors, embedded resistors, thin-film transistors and micro supercapacitors. The third scientific subject is the research on graphene-based separation membranes: molecular dynamics simulation study on the mechanisms of the transport of molecules, vapors and gases through nanopores in graphene membranes, experimental works investigating selective transport of different molecules through nanopores in single-layer graphene and graphene-based membranes toward the water desalination, chemical mixture separation and gas control. Various applications of graphene in bio-medicine are the contents of the fourth scientific subject of the review. They include the DNA translocations through nanopores in graphene membranes toward the fabrication of devices for genomic screening, in particular DNA sequencing; subnanometre trans-electrode membranes with potential applications to the fabrication of very high resolution, high throughput nanopore-based single-molecule detectors; antibacterial activity of graphene, graphite oxide, graphene oxide and reduced graphene oxide; nanopore sensors for nucleic acid analysis; utilization of graphene multilayers as the gates for sequential release of proteins from surface; utilization of graphene-based electroresponsive scaffolds as implants for on-demand drug delivery etc. The fifth scientific subject of the review is the research on the utilization of graphene in energy storage devices: ternary self-assembly of ordered metal oxide-graphene nanocomposites for electrochemical energy storage; self-assembled graphene/carbon nanotube hybrid films for supercapacitors; carbon-based supercapacitors fabricated by activation of graphene; functionalized graphene sheet-sulfure nanocomposite for using as cathode material in rechargeable lithium batteries; tunable three-dimensional pillared carbon nanotube-graphene networks for high-performance capacitance; fabrications of electrochemical micro-capacitors using thin films of carbon nanotubes and chemically reduced graphenes; laser scribing of high-performance and flexible graphene-based electrochemical capacitors; emergence of next-generation safe batteries featuring graphene-supported Li metal anode with exceptionally high energy or power densities; fabrication of anodes for lithium ion batteries from crumpled graphene-encapsulated Si nanoparticles; liquid-mediated dense integration of graphene materials for compact capacitive energy storage; scalable fabrication of high-power graphene micro-supercapacitors for flexible and on-chip energy storage; superior micro-supercapacitors based on graphene quantum dots; all-graphene core-sheat microfibres for all-solid-state, stretchable fibriform supercapacitors and wearable electronic textiles; micro-supercapacitors with high electrochemical performance based on three-dimensional graphene-carbon nanotube carpets; macroscopic nitrogen-doped graphene hydrogels for ultrafast capacitors; manufacture of scalable ultra-thin and high power density graphene electrochemical capacitor electrodes by aqueous exfoliation and spray deposition; scalable synthesis of hierarchically structured carbon nanotube-graphene fibers for capacitive energy storage; phosphorene-graphene hybrid material as a high-capacity anode material for sodium-ion batteries. Beside above-presented promising applications of graphene and graphene-based nanostructures, other less widespread, but perhaps not less important, applications of graphene and graphene-based nanomaterials, are also briefly discussed.

We review fundamental aspects of the non-equilibrium Green function method in the simulation of nanometer electronic devices. The method is implemented into our recently developed computer package OPEDEVS to investigate transport properties of electrons in nano-scale devices and low-dimensional materials. Concretely, we present the definition of the four real-time Green functions, the retarded, advanced, lesser and greater functions. Basic relations among these functions and their equations of motion are also presented in detail as the basis for the performance of analytical and numerical calculations. In particular, we review in detail two recursive algorithms, which are implemented in OPEDEVS to solve the Green functions defined in finite-size opened systems and in the surface layer of semi-infinite homogeneous ones. Operation of the package is then illustrated through the simulation of the transport characteristics of a typical semiconductor device structure, the resonant tunneling diodes.

This study reports the successful synthesis of quantum-sized copper nanoparticles (Cu Nps) and their incorporation into titanium dioxide (TiO₂) thin films. To mitigate the rapid oxidation of Cu, the nanoparticles were sandwiched between two layers of TiO₂, reducing direct exposure to atmospheric oxygen. The resulting films were characterized using X-ray diffraction, UV–Vis spectroscopy, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. The modified TiO₂ films demonstrated enhanced photocatalytic efficiency for the degradation of Methylene Blue (MB) dye. However, their performances as photoanodes in dye-sensitized solar cells showed a reduction in short-circuit current inspite of the improved open circuit voltage, ultimately leading to decreased overall efficiency.

Silicon aluminum oxynitride (SiAlON) has attracted significant attention due to its outstanding mechanical, thermal, and chemical properties. Hight Y₂O₃ content mixed oxides of Al₂O₃–Y₂O₃–SiO₂ (AYS frits) are usually used for preparation of SiAlON to reduce the calcination temperature but controlling synthesis conditions remains challenging, as phase formation varies with composition and preparation method. Here, we examine the phase evolution of AYS frits desired from SiO₂, Y₂O₃ and Al₂O₃ nanoparticles during thermal treatment. The AYS frits with different compositions (2A7Y1S and 1A8Y1S) were synthesized, and the effects of firing temperature and duration on their phase formation and crystal structure were investigated. The results showed that the 2A7Y1S and 1A8Y1S frits prepared from nano oxides exhibited lower transition and crystallization temperatures compared to those synthesized by conventional mixing methods. We also found that the SiAlON ceramics synthesized from AYS frits exhibit superior properties including higher bulk density, lower porosity, improved water adsorption, and excellent hardness. The optimal sample demonstrated a bulk density of 3.02 g cm⁻³, porosity of 1.85%, water adsorption of 0.61%, and a hardness of 12.5 GPa. These findings provide valuable insights into optimizing synthesis conditions for advanced ceramic applications.

Over the past 10 years, nanotechnology has become a potentially revolutionary breakthrough in the areas of the industry, environment, and consumers. The fields of green chemistry and nano-biotechnology have immense promise for producing novel and exceptional products that are favourable to the modern farming systems. Due to its various applications, green technology is a fast-expanding scientific topic that has gained prominence recently. This research summarized the current information of various green synthesis methods utilizing plant components and microorganisms for nanoparticle production. Employing of nanomaterials promotes ‘biosynthesis’ and minimize the need for harmful substances and synthesis costs. We examine the biosynthesis of nanoparticles in this paper, as well as their prospective applications for environmentally friendly agriculture. With the use of nanotechnology, a whole new kind of fertilizer known as biosynthesized nano fertilizers has been created. These nano-biofertilizers can increase nutrient efficiency, minimize nutrient excess, increase plant growth, improve soil health, and boost crop development. They have various advantages over conventional fertilization techniques. Our survey indicates that the agriculture industry may benefit greatly by the utilization of nanotechnology as it provides a state-of-the-art, eco-friendly farming option.

A NiFe₂O₄/PEG nanocomposite (NF/PEG NCs) was prepared using a simple precipitation method. The composite was placed on a glassy carbon electrode as a modifier to enhance the dopamine (DA) detection. The NF/PEG composite was compared with the NF nanoparticles, showing with improved sensing due to incorporating polyethylene glycol (PEG). This enhancement increased the electrocatalytic properties of the electrode, facilitating better detection of analytes. The electrochemical sensing of DA using NF/PEG was analyzed through cyclic voltammetry, amperometry, and differential pulse voltammetry. The detection limit of DA was found to be 18.87 nM by DPV. The NF/PEG NCs served as an electrocatalyst to detect DA by mimicking peroxidase activity in the presence of hydrogen peroxide (H₂O₂) and 3,5,3′,5′-tetramethylbenzidine (TMB) as a coloring agent. The NF/PEG NCs exhibited enhanced electrocatalysts in both the methods for selective detection of DA due to the synergic effect of NF/PEG.

In this work, Bi₂O₃/CeO₂ nano-spheres, aiming to act as photocatalysts for treating organic pollutants in aqueous solutions, were synthesized by a simple hydrothermal-reaction method. The produced materials were characterized by x-ray diffraction, field emission scanning electron microscopy, ultraviolet and visible spectroscopy (UV–vis), and Fourier transform infrared spectroscopy. The 3% and 9% Bi₂O₃ doped materials were crystallized in the fluorite CeO₂ crystal structure, where an angular shift of ∼0.17° was observed in the (111) and (200) planes of CeO₂. The crystallite sizes were calculated as 10.98 and 11.90 nm for 3% and 9% Bi₂O₃:CeO₂, respectively, compared to the larger sizes of 24.4 and 13.39 nm for pure Bi₂O₃ and CeO₂. The surface morphology of CeO₂ nanoparticles doped with 9% Bi₂O₃ is smooth and uniform, like the particles of pure CeO₂ powder, whereas pure Bi₂O₃ powder particles exhibit a nonuniform morphology. The bandgap energy of the 3% and 9% Bi₂O₃:CeO₂ nanocomposites was 2.54 and 2.44 eV, respectively, which are lower than the bandgap energy of pure Bi₂O₃ (2.69 eV) and pure CeO₂ (2.57 eV). The experimental results of their photocatalytic activity, tested by methylene blue degradation in aqueous solution, were very promising. The first principles calculations have been employed to provide a solid support to our experimental findings for Bi-doped CeO₂ which shows promising results.

This review delves into carbon quantum dots (CQDs), highlighting their synthesis, unique properties, and broad applications across environmental, biomedical, and industrial fields. CQDs, with their tunable fluorescence, high biocompatibility, and sustainable production methods, are increasingly valuable for pollutant sensing, bioimaging, drug delivery, and photocatalysis. Structurally, CQDs feature a graphitic core and surface functional groups that govern their optical and chemical characteristics, while functionalization and doping can enhance their stability and fluorescence. However, obstacles such as low quantum yields, synthesis reproducibility, and toxicity concerns still limit their potential in broader applications. In environmental uses, CQDs are effective as photocatalysts and adsorbents, aiding in pollutant removal and water purification. In biomedicine, their low toxicity and targeted fluorescence make CQDs suitable for drug delivery and antimicrobial and anticancer therapies. The review also explores the use of green, waste-based materials for CQD production, supporting sustainable and scalable manufacturing. Looking forward, research aims to develop multifunctional CQD hybrids for use in nanoelectronics and photovoltaics, and to optimize CQD properties for greater reliability in real-world applications. By addressing these challenges and prioritizing scalable, eco-friendly production, CQDs have the potential to be transformative materials, enabling sustainable advances across various scientific and industrial domains.

The demand for efficient energy storage solutions has become increasingly imperative in today’s rapidly evolving technological landscape. Researchers from various disciplines have been diligently exploring potential avenues for enhancing the performance of electrode materials. Various materials have been explored for electrode materials. Among these, binary spinels such as MnCo₂O₄, NiCo₂O₄, Co₂TiO₄, etc, have emerged as promising candidates due to their exceptional super-capacitive properties. This review article aims to provide an in-depth exploration of recent developments in the synthesis, charge-storage mechanism, and utilization of different MnCo₂O₄-based nanostructures for energy storage applications. The discussion encompasses a comprehensive analysis of synthesis methods and further highlights their potential in electrochemical properties. Through a systematic examination of the latest research findings, this review seeks to shed light on the evolving landscape of spinel-based nanostructures and their pivotal role in advancing energy storage technologies. By consolidating the current state of knowledge and identifying areas for further investigation, this work contributes to the collective effort to develop sustainable and high-performance energy storage solutions.

The field of cancer treatment is undergoing a paradigm shift with the emergence of nanotechnology, particularly the use of nanoparticles (NPs) and their potential synergy with cold atmospheric plasma (CAP) and electroporation. This paper provides a comprehensive review of the current progress, challenges, and future prospects in utilizing NPs, CAP, and electroporation for cancer therapy. The investigated studies highlight the advantages of NPs, such as their small size, large surface area, and controlled drug release properties, making them efficient in delivering therapeutic agents to specific targets. Additionally, they explore the potential of metallic NPs, such as gold, silver, titanium, and palladium, in targeted drug-delivery systems, showcasing their ability to enhance cancer treatment through properties like tunable optical properties and increased drug circulation time. The combination of NPs with CAP and electroporation is shown to amplify cytotoxicity and therapeutic efficacy, leading to increased cancer cell death and improved treatment outcomes. Furthermore, the studies address the molecular mechanisms and outcomes of these combination therapies, emphasizing the potential for enhanced targeted drug delivery and improved therapeutic outcomes in cancer therapy. This review aims to contribute towards the development of future therapeutic strategies and optimized cancer treatment modalities.

Emerging research in conductive and composite polymer nanoinks (CCPNIs) demonstrate remarkable advantages in electrical, thermal, and mechanical properties which are highly desired for printable applications. The development of suitable scalable production techniques can address the demand for wearable, printable, and flexible nanoink-based electronic applications. In this review we present a comparative analysis for contact based techniques such as screen printing (SP), nano imprint lithography (NIL) and non-contact printing techniques such as inkjet printing (IJP), aerosol jet printing (AIP) and 3D printing with a focus on CCPNIs. We discuss the application of these techniques across various electronic domains such as wearable electronics, flexible sensors and robotics which rely on scalable printing technologies. Among the techniques reviewed, SP stands out as particularly suitable and sustainable, primarily due to its scalability and efficiency. It is capable of producing between 1,000 and 5,000 parts per hour, while maintaining a practical resolution range of 1000 μm (±5–10%). SP is suitable for applications in printed electronics, where cost-effectiveness, simplicity, and scalability are of focus. In contrast, for complex and multidimensional printing, 3D printing shows promise with an excellent resolution which are crucial for industrial-scaled production.

Cancer remains a formidable global health challenge, with millions of lives lost annually and a projected increase in cases, particularly in regions like South Central Asia, Europe, Eastern Europe, etc, Traditional cancer treatments, including chemotherapy, radiotherapy, and surgery, face limitations in effectively managing the complex tumor microenvironment and addressing the diverse characteristics of cancer cells. Nano-oncology has emerged as a promising frontier in cancer therapy, utilizing nanoscale materials to deliver therapeutic agents with precision and efficacy. The benefits of nanoparticle-based drug delivery systems are the ability to target tumor cells while minimizing adverse effects and overcoming multidrug resistance. Advancements in hybrid nanoparticle development have further enhanced the stability and performance of drug delivery systems, offering new avenues for cancer treatment. Moreover, nanoparticle-based therapies hold the potential to modulate the immunosuppressive tumor microenvironment and improve outcomes in immunotherapy. The review provides a comprehensive overview of nanotherapeutic products currently in various preclinical and clinical study stages, focusing on their success rates in lung and breast cancers compared to conventional chemotherapeutic drugs. By elucidating the landscape of nano-oncology and evaluating its efficacy in specific cancer types, this review aims to shed light on the transformative potential of nanoparticle-based approaches in cancer treatment and diagnosis. They are exploring nano-oncology promises to pave the way for innovative strategies in combating cancer and improving patient outcomes globally.

Graphene is considered a highly promising material due to its distinct properties, such as a high aspect ratio and superior mechanical, thermal, and optical characteristics. Notably, graphene and its derivatives exhibit a pronounced photothermal effect, positioning them as key materials for efficient solar energy harvesting and conversion. In this study, we evaluate the impact of the surface area of several types of commercial graphene on their water vapor generation capability. As a result, GC 750-based absorber layer shows a light absorption rate exceeding 88% across the full UV-Vis and near-infrared spectrum. This results in the highest photothermal conversion efficiency observed in the GC 750 sample, with the surface temperature of the dry film reaching 52°C under illumination. The surface area of GNPs increases from 50 to 750 m2/g, resulting in an increasing water evaporation rate from 0.717 to 0.814 kg.m-2.h-1 under 1 sun irradiation. This enhancement can also be partly attributed to the optimized structure of the GC 750-based absorb layer and the enhanced air convection properties of the material, which has a larger surface area and pore volume.

Electrochemical water splitting is a promising method for sustainable hydrogen production with low carbon emissions. Molybdenum disulfide (MoS₂), a two-dimensional transition metal dichalcogenide (TMD), has gained attention as a cost-effective alternative to noble metal-based electrocatalysts. This study investigates the effect of precursor molar ratios on the hydrogen evolution reaction (HER) performance of MoS₂ synthesized on 3D conductive carbon cloth using the hydrothermal method. MoS₂ was synthesized with varying molybdenum-to-sulfur molar ratios (1:4, 1:2, and 1:1), and characterization confirmed the formation of the 2H-MoS₂ phase, with an additional α-MoO₃ phase. Among the samples, MoS₂-14 (1:4 ratio) exhibited the highest HER activity, with a low onset potential of 155 mV, and a Tafel slope of 58 mV/dec. MoS₂-14 had the largest electrochemical active surface area (C_dl= 251 mF/cm²) and the lowest charge transfer resistance (R_ct = 1.28 Ω), indicating superior conductivity and catalytic performance. Morphological analysis showed that MoS₂-14 had a more amorphous structure further enhancing its HER efficiency. These findings demonstrate that precursor molar ratios significantly impact the structural, morphological and electrocatalytic properties of MoS₂, with a 1:4 molybdenum-to-sulfur ratio offering optimal performance, providing valuable insights for rational design of high-performance MoS₂-based electrocatalysts

Nanoscience has emerged as a great solution for environmental and health issues. Materials with versatile application, economic and eco-benign accompanied with facile synthesis methods are an indispensable requirement for current society especially when we are on the verge of a chaos with intensified pollution and health issues. In the present work we report, for the first time, photocatalytic degradation of Methylene blue (MB) dye under tungsten bulb (TB) for water purification along with antibacterial properties of spinel MgCo2O4 (MgCo) synthesized by facile solution combustion method. The structural (XRD) and the morphological studies (SEM and TEM) show that the prepared sample is phase pure with crystalline nature and has a spongy morphology. FTIR, DRS and EDS analysis gave more insight about the prepared material. Further the photocatalytic degradation of MB under different light sources for different pH was studied which shows a percentage degradation of 96.73% in 90 min after the irradiation by tungsten bulb (500 Watts) for a catalyst dosage of 25mg. Additionally, the material exhibited excellent reusability, maintaining an efficiency of 94.2% even after five consecutive cycles. The antibacterial activity was tested against both Gram-positive and Gram-negative bacteria, showing strong inhibition for all four tested strains, with the highest inhibition zone observed for Bacillus subtilis. 

Transparent heaters (HT) based on silver nanowires (AgNWs) often encounter issues with high resistance at the junctions between the wires, resulting in localized high Joule-heating temperatures that can lead to the breakdown of the AgNWs. In this paper, an indim tin oxide (ITO) layer was coated on AgNWs by sputtering method to improve the electrical and thermal properties of AgNW THs. Initially, the bare AgNW HT had a high sheet resistance of about 205.43 Ω/. After ITO sputtering, the sheet resistance sharply decreased from 205.43 Ω/ to 30.17 Ω/, while the transmittance at the wavelngth of 550 nm was slightly reduced from 93.01% to 84.21%. The optimal AgNW/ITO thermal heater (TH) was observed at 10 sputtering min, resulting in a sheet resistance of 30.17 Ω/, a transmittance of 84.21%, and a figure of merit of 69.63. The maximum Joule-heating temperature of the AgNW/ITO reached 250.9 °C at 11 V, which was 157 °C higher than that of bare AgNW, with a more uniform heat distribution. Additionally, the thermal stability of the AgNW/ITO THs was improved by 140 °C compared to bare AgNW TH during hot plate testing. These results demonstrate that ITO-coated AgNW has excellent potential for applications in transparent heaters.

The high spontaneous magnetization (Msp) and large magneto-crystalline anisotropy energy (Ku) make NdFeB-based alloys and permanent magnets prepared thereof to stay the ace of the overworld magnet market. Anyway, the search of novel approaches for massive production of high-performance NdFeB-based melt-spun ribbons is currently continued to create new opportunities for manufacturing high performance bonded magnets. This paper dealt with the effects of Bismuth (Bi) doped into the mother phase of slightly enriched soft phase Fe modified a little by Co, Nd2(Fe0.93Co0.07)15B. The Bi-doping has been performed by using the pseudo-eutectic phase of Nd92Bi8. This doping helps reducing the grain size, enhancing the texture degree and reinforcing the crystal growth along the ribbons’ surface and totally improving the magnetic performance of doped NdFeB-based ribbons. The present energy product (BH)max of this kind of ribbons is around 20 MGOe. The route of production and impacts of dopant on the phase, microstructure and magnetic properties were investigated in details.