Surface Area Of Nanoparticles Research Articles

Novel insight into the microstructure evolution and strengthening mechanism of nanocrystalline copper prepared by hot-pressing sintering: A molecular dynamics study

An integrated strategy is proposed for the design and performance evaluation of nanocrystalline (NC) copper prepared by using the hot-pressing sintering process (HPS). Molecular dynamics (MD) simulation is employed to investigate the microstructure and performance of the prepared NC copper. The merging of nanoparticles (NPs) during HPS is influenced by the initial surface area of NPs. A higher surface area corresponding to a smaller size of NPs will promote the merging of NPs by providing more interface for the diffusion of atoms. The designed grain size can be obtained by adjusting the initial size of NPs. The mechanical properties of NC copper do not present a liner correlation with the grain size. With the grain size increasing from 1.51 to 4.10 nm, the strength and ductility of NC copper first increase but then decrease. The cooperating influence of the grain boundaries with high strength and the matrix with high ductility on the mechanical properties is revealed. This study highlights the relationship between microstructure evolution and mechanical properties in NC metals, offering insights into designing high-performance NC materials. The MD model can be extended into another case with a larger size and time scale.

Plasmon-Exciton Strong Coupling in Colloidal Au Nanocubes with Layered Molecular J-Aggregates.

Strong coupling between light and matter forms hybrid states, such as exciton-polaritons, which are crucial for advancements in quantum science and technology. Plasmonic metal nanoparticles, with their ultrasmall mode volumes, are effective for generating these states, but the coupling strength is often limited by surface saturation of excitonic materials. Additionally, cubic nanoparticles, which can generate strong local fields, have not been systematically explored. This study investigates strong coupling in Au nanocubes (AuNCs) coupled with J-aggregates, observing spectral splitting in both extinction and scattering spectra. Our findings suggest that smaller AuNCs, with higher-quality resonances and reduced mode volumes, achieve stronger coupling. Furthermore, a layer-by-layer (LBL) coating of J-aggregates on AuNCs results in a ∼21% increase in coupling strength. Simulations reveal the mechanism behind the enhanced coupling and confirm that the layering method effectively increases coupling, surpassing the limitations of the finite surface area of nanoparticles.

Non-linear optics for an online probing of the specific surface area of nanoparticles in the aerosol phase

In the present study the generation of non-linear optical (NLO) effects, such as second harmonic generation (SHG), by black carbon particles, also named soot, and by other types of nanoparticles in aerosol phase is quantified and analysed. Its potential for measuring the specific surface area of an aerosol is put forward. SHG is a Non Linear Optical phenomenon that is typically used in biosciences and fundamental physics and has shown to have large potential for the investigation of surface sensitive phenomena. It exists in two forms, coherent SHG and incoherent SHG, also named Hyper Rayleigh Scattering (HRS). While applications on particles in solution or organic molecules located on the surface of droplets exist, the SHG naturally induced by solid nanoparticles in aerosol phase without any SHG enhancing additive has neither been detected nor quantified yet. The present work aims at narrowing this gap by exposing a jet of well-characterized nanoaerosols to a femtosecond laser featuring high peak pulse energies allowing to induce NLO phenomena. The experiments are carried out in an innovative optical setup allowing to analyse the NLO response resolved in time, wavelength and angle, thus having the capability to isolate SHG from other phenomena, such as laser filamentation. The optical setup was calibrated in order to quantify the generated signal power and optimized in order to have a high sensitivity and in order to avoid NLO generation from its own optical elements. The results confirm that soot particles, as well as DEHS droplets and arc generated carbon nanoparticles, feature SHG at intensities that are more than 7 orders of magnitude smaller than that of static light scattering. SHG depends in particular on aggregate and/or monomer size. On the other hand, SHG induced by soot does not seem to depend on the organic or elementary carbon content. The experiments also show that the detected NLO signal increases linearly with particle surface area, independently of the particle shape or composition. Finally, the angular response of NLO signal is fundamentally different from that of linear scattering. Due to the isotropic nature of the angular response, the observed SHG signal is probably non-coherent and thus related to Hyper Raleigh Scattering. These findings show the potential of non-linear optics, in particular to quantify in situ the specific surface of an aerosol. Giving access to this information which is crucial in the evaluation of toxicity of aerosols, the present work can thus give way to a new class of laser based diagnostics for aerosols.

Silica/klucel nanocomposite as promising durable adsorbent for lead removal from industrial effluents

The removal of heavy metals, such as lead, from industrial wastewater is imperative due to their detrimental effects on both human health and the environment. This study delves into investigating the feasibility of employing a novel adsorbent, specifically a silica/klucel nanocomposite, for effectively extract lead from industrial effluents. The synthesis of this nanocomposite involved a simple and cost-effective method, combining silica nanoparticles with klucel. XRD, FTIR, E-SEM, Raman, and N2 gas adsorption at − 196 °C tools were employed to prospect the formation of silica/klucel nanocomposite. Outstandingly, treating 50 ml of 50 mg/l of lead with 10 mg of adsorbent exhibited rapid removal, which reached a maximum (95%) at 60 min contact time. The resulting composite demonstrated remarkable adsorption capabilities, primarily attributed to two factors: the expansive surface area of silica nanoparticles 139.1 m2/g and the porous structure provided by klucel. Through batch adsorption experiments, the nanocomposite’s proficiency in removing lead ions from aqueous solutions became evident. The kinetics of the adsorption process were found to adhere closely to a pseudo-second-order model, hinting at chemical adsorption as the rate-determining step. Langmuir isotherm model revealed that lead ions tend to form a monolayer on the surface of the nanocomposite and the maximum adsorption capacity (qm) was 63.938 mg/g. Additionally, the nanocomposite, exhibited notable stability and could be reused multiple times, where 65% removal efficiency was announced until the 7th cycle without significant degradation in performance. In summary, the silica/klucel nanocomposite emerges as a promising and eco-friendly adsorbent for removing lead from industrial effluents. Its efficient performance and sustainability offer a compelling solution to combat heavy metal contamination, thereby contributing to environmental preservation and human well-being.

Effect of Electron Irradiation on the Optical Properties of Zinc Oxide Powder Modified by Magnesium Oxide Nanoparticles

The effect of modifying ZnO powders with MgO nanoparticles (with a concentration of 0.1–10 wt. %) on their diffuse reflectance spectra in the region of 0.2–2.5 μm before and after irradiation with 30 keV electrons was studied. Modification of ZnO powder was carried out by MgO nanopowder with concentrations from 0.1 to 10 wt. % using a solid-state method at 650°C heating temperature. X-ray diffraction analysis showed that this method of modification there is no formation of additional phases. It has been established that zinc oxide structure symmetry belongs to the P63mc space group, magnesium oxide – to the Fm–3m space group. The spectral reflectance of such powders in the visible region is over 90%. Under irradiating by 30 keV electrons of initial and modified ZnO powders, as well as MgO nanopowder, a decrease in their reflectance recorded in the entire studied region of the spectrum. It has been established that modification with MgO nanoparticles at a concentration of 3 wt. % leads to an increase in radiation resistance by a factor of 1.32 compared to unmodified samples. This effect is determined by the sink of radiation defects on the large specific surface area of nanoparticles.

Synthesis and characterization of mesoporous silicate as core and low generation polyamidoamine dendrimer as shell for delivery of 5-fluorouracil from their nano complex

Modern nanomedicine delivers drugs to malfunctioning cells. Several synthetic processes can change the shape, particle size, polydispersity index, surface area, and porosity of mesoporous silica nanoparticles (MSNs). Polyamidoamine (PAMAM) dendrimers are attractive polymers with circular forms, uniform distribution, well-structured branching, internal cavities, and surface terminal groups. The objective of this study is to deliver 5-fluorouracil (5-FU) as passive targeting to carcinogen cells via MSN-PAMAM-G3 nanoparticles. This study involved the direct and adaptable synthesis of MSN as the core vehicle, together with third-generation PAMAM dendrimers as the vehicle shell, with the goal of delivering the 5-FU in a targeted and controllable manner. Tetraethyl orthosilicate (TEOS) and cetyltrimethylammonium bromide (CTAB) are used as templates to make the center nanoparticle. Methyl acrylate (MA) and ethylenediamine (EDA) are monomers that cause the formation of branches in PAMAM. The obtained particles were fully characterized in terms of particle size, polydispersity index, zeta potential, thermal behavior, morphology, pore diameter, pore volume, and specific surface area. The particle size of MSN-PAMAM-G3s showed around 187.71 ± 3.97 nm, with a polydispersity index of 0.17 ± 0.01 and zeta potential of 32.17 ± 1.30 mV. By reducing the ratio of drug to vehicle from 1 to 0.25, a significant increase in the EE% of 5-FU from 21.36 ± 0.70 to 43.12 ± 0.67 was observed. The release of 5-FU from the vehicle (5-FU@MSN and 5-FU@MSN-PAMAM-G3) was shown to be considerably higher in an acidic medium (pH = 5.5) in comparison to a neutral medium (pH = 7.4) (P-value<0.05). Furthermore, in both acidic and neutral conditions, 5-FU release was sustained from the vehicle rather than the 5-FU solution. Our research revealed that the MSN-PAMAM-G3 nanoparticles effectively regulated the encapsulation and release of 5-FU, providing pH-sensitive and sustained medication delivery. It is asserted that this nanocarrier has the potential to effectively deliver 5-FU to cancer cells.

CaAl1.5Fe0.5O4/6%Ni-ZnO nanocomposites: Synthesis, characterization and effective photocatalyst for the photocatalytic degradation of methylene blue dye

This study focuses on synthesizing and analyzing properties of calcium aluminate photocatalytic nanoparticles using the microwave (MW) combustion method by following the rules of green chemistry and investigates their effectiveness in the adsorption of methylene blue (MB) dye which is a crucial contaminant that enters water resources. The synthesized nanoparticles, including CaAl2O4 (CAO), CaAl1.5Fe0.5O4 (CAFO), 6 %Ni-ZnO (NZO), and CaAl1.5Fe0.5O4/6%Ni-ZnO (CAFONZO) composites, were characterized using various techniques. XRD analysis confirmed the formation of spinel structures in all samples. The crystallite size and lattice constants were determined, showing a reduction in Crystallite size of CAO from 45.98 nm to 37.55 nm after Fe3 + doping. Then, with the formation of CAFONZO Crystallite size 13.99 nm was obtained. FT-IR analysis revealed the chemical interactions between atoms in the spinel structures Nitrogen adsorption/desorption isotherms were used to determine the specific surface area of nanoparticles, pore volume, and pore size. Specific surface area of CAO, CAFO, and CAFONZO are 1.637, 1.745, and 9.903 (m2/g), respectively. SEM and TEM images provided insight into the morphology and size of the nanoparticles. According to TEM images, after Fe3 + doping, the size of particles decreased from 85 to 32 nm. UV-DRS was performed to determine the optical band gap energy of the photocatalysts. The calculated band gap values of pure CAO, CAFO, and NZO nanoparticles were 3.2 eV, 2.5 eV, and 2.7 eV, respectively. Mott-Schottky analysis indicated the type of semiconductors and the energy levels of the conduction and valence bands. Valence band (VB) values of CAFO and NZO are 2.86 eV and 2.03 eV, respectively. The photocatalytic activity of the nanoparticles was evaluated by degrading MB under visible light illumination. The adsorption studies were conducted by varying the dosage, pollutant concentration, and pH. The results showed that CAFONZO nanoparticles exhibited the highest photocatalytic efficiency, achieving 96 % degradation of MB within 120 min. The combined photocatalyst demonstrated improved efficiency compared to the individual components.

Disposable electrochemical aptasensor with mesoporous carbon spheres modified screen-printed dual-working electrodes for Pb2+ and Hg2+ detection

Electrochemical biosensing combined with screen-printed paper technology provides an effective strategy for the quantitative analysis of metal ions, particularly suitable for in-situ determination. In this study, a disposable, economical and user-friendly screen-printed dual-working electrodes (SPDEs) aptasensor system for the determination of lead ions (Pb2+) and mercury ions (Hg2+) was described. The sensor system consists of dual-working electrodes, a counter electrode and a reference electrode fabricated using screen printing technology. The aptasensor demonstrates high sensitivity and selectivity towards Pb2+ and Hg2+, owing to the larger specific surface area (1334.7 m2/g) and excellent conductivity of mesoporous carbon nanoparticles (MCNs). Additionally, the specific recognition ability and high affinity of G-quadruplex and T-Hg2+-T structures for Pb2+ and Hg2+, respectively, further enhance the performance. Under optimized experimental conditions, the aptasensor achieves a low limit of detection (LOD) of 0.088 ng/mL for Pb2+ and 0.0007 ng/mL for Hg2+ (S/N = 3), a wide linear range (0.1–1000.0 ng/mL for Pb2+ and 0.001–100.0 ng/mL for Hg2+), and high accuracy (relative standard deviation, RSD≤10.0 %) and selectivity. Importantly, the SPDEs aptasensor can detect Pb2+ and Hg2+ in a sample without competition and interference, achieving accuracy comparable to that of commercial inductively coupled plasma mass spectrometry (ICP-MS). These advantages make the SPDEs aptasensor highly suitable for practical applications in environmental monitoring, food safety, and clinical diagnosis.

Optimization of Properties of Iron Oxide Nanoparticles Synthized by SolGel Method

In this study, the effects of pH value and capping agent on the morphology, pore structure and size of iron oxide nanoparticles were investigated systematically to obtain optimum properties. Iron oxide nanoparticles were synthized by sol-gel method. Polyvinyl alcohol (PVA) was used as capping agent by adding to the solution at 70 °C. After the drying process the powders were heat treated at 250 °C for 2 h under air atmosphere. Particle size of each sample was determined by using ZetaSizer instrument. X-ray diffraction (XRD) technique was employed for structural properties of iron oxide nanoparticles, FE-SEM (Field Emmision Scanning Electron Microscopy) was used to analyze the morphology of the powders. Magnetic properties of the nanoparticles were measured by VSM (Vibrating Sample Magnetometer) under air atmosphere at room temperature. Spesific surface area, porosity and pore size distribution of iron oxide nanoparticles were calculated by Brunauer-Emmett-Teller (BET) instrument. The results indicated that formation of the γ-Fe2O3 is sensitive to either the pH value of the solution or the capping agent, for the uncoated samples when pH value of the solution is adjusted to 2.5, α-Fe2O3 phase was detected as a single phase. When the solution was neutralized, γ-Fe2O3 was formed as the major phase in the microstructure, γ-Fe2O3 phase was formed as the major phase in the PVA coated samples leading to highest value of 50.33 emu/g measured in the sample of PVA8.5. For the PVA coated samples, specific surface area is in the range of 15.73 – 20.81 m2 /g, the intervals of pore volume and average pore width are increased to 0.099 – 0.121 cm3 /g and 23.19 – 23.07 nm respectively.

Fabrication of high performance BaSnO3/PVDF piezoelectric nanogenerator through high surface area BaSnO3 nanoparticle assisted β-phase stabilization of PVDF

Piezoelectric nanogenerators (PENGs) are becoming increasingly popular for energy generation and their use in smart electronics. In this study, a barium stannate (BaSnO3)-doped polyvinylidene fluoride (PVDF)-based PENG has been fabricated for the first time. The β-phase of PVDF was stabilized by optimizing the doping of BaSnO3 nanoparticles without the need for external electrical poling. The high surface area of the BaSnO3 nanoparticles promotes the nucleation of the polar β-phase in PVDF through electrostatic interaction. A low-cost solution casting method was used to prepare flexible BaSnO3/PVDF nanocomposite containing 5 wt% BaSnO3, which was then shaped and sandwiched between copper electrodes and protected with a thin PDMS layer to create the final PENG. The fabricated PENG can generate up to ∼41 V of voltage, ∼1.51 µA of current and ∼18.1 µW/cm2 of power density when ∼15.7 kPa pressure is applied by a human finger. The PENG can also charge capacitors, power up 16 LEDs in a series connection, and power other small electronics such as wristwatches, speakers, and calculators. Additionally, the PENG can activate the electrochromic material methyl viologen, which is commonly used in smart window applications.

Nitrogen Doped Graphene Aerogel Inserted By Carbon Black As Novel Catalyst Support for Low Temperature Hydrogen Fuel Cells

Carbon supported Pt nanocatalysts, which are commonly used in hydrogen fuel cells, suffer from Pt degradation and carbon corrosion. That causes the high cost and limited lifetime of the fuel cell1. Developing catalyst support materials with high surface area, high electrical conductivity, stability and good interaction with catalyst is an effective solution to address this issue.To enhance the activity and durability of Pt-based catalysts for hydrogen fuel cells, graphene aerogels (GA) are a prospective material with rich porous 3D-structure, large surface area, high electrical conductivity, and good electrochemical stability. They also can improve the tolerance of catalyst CO poisoning and avoid graphene stacking by integrating 2D sheet structure into 3D aerogel structure2, 3. Some research show that the nitrogen doped on the surface of carbon materials could improve ORR activity and electronic conductivity by changing the local electronic structure as well as providing a stable anchor point for pt nanoparticles to enhance the durability of catalysts4, 5.However, most GAs are made from graphene oxide (GO) produced by Hummers method which may lead to safety and environmental issue due to the usage of highly toxic and corrosive chemicals2, 5. Also, there are few articles on the application of GA in fuel cells. It may be limited by the collapse and loss of pore structure caused by compression in a fuel cell setup.In this work, graphene oxide produced by electrochemical exfoliation (EGO) was used to prepare N-doped graphene aerogel (NGA) via hydrothermal treatment with ammonia solution as nitrogen source. Moreover, NGA was mixed with carbon black (CB) as a hybrid support material that can avoid collapse of the macropore and generate a graphene-carbon network to provide large surface area for Pt nanoparticles and improve the performance of the fuel cell. Figure1 shows preliminary characterization results of NGA and performance of NGA-CB supported Pt catalysts with different content of NGA. Rich macro-mesoporous structure of NGA can be observed in the SEM image (Figure 1 (a)). Pt catalyst with 20% NGA has a maximum power density of 838 mw cm-2 which is a 31% improvement over that of Pt/CB (Figure 1 (b)).In conclusion, this study presents a fast, efficient and environmentally friendly way to synthesize nitrogen doped GA. The introduction of NGA into CB as catalyst supports can improve the electrochemical active surface area and performance of fuel cells due to graphene aerogel's high conductivity and porosity. Besides, it is effective to enhance the utilization of Pt and durability of catalysts. This will help to reduce the cost of fuel cells and facilitate their commercialization in various fields of application.Figure 1 (a) SEM images of dried NGA. (b) Performance of Pt/NGA-CB with various content of NGA compared to Pt/CB catalyst in a hydrogen fuel cell at 60 ℃ with 100% RH. References Liu, J.; Wu, X.; Yang, L.; Wang, F.; Yin, J., Unprotected Pt nanoclusters anchored on ordered mesoporous carbon as an efficient and stable catalyst for oxygen reduction reaction. Electrochimica Acta 2019, 297, 539-544.Sarac Oztuna, F. E.; Barim, S. B.; Bozbag, S. E.; Yu, H.; Aindow, M.; Unal, U.; Erkey, C., Graphene Aerogel Supported Pt Electrocatalysts for Oxygen Reduction Reaction by Supercritical Deposition. Electrochimica Acta 2017, 250, 174-184.Wu, Z.-S.; Yang, S.; Sun, Y.; Parvez, K.; Feng, X.; Müllen, K., 3D Nitrogen-Doped Graphene Aerogel-Supported Fe3O4 Nanoparticles as Efficient Electrocatalysts for the Oxygen Reduction Reaction. Journal of the American Chemical Society 2012, 134 (22), 9082-9085.Li, O. L.; Chiba, S.; Wada, Y.; Panomsuwan, G.; Ishizaki, T., Synthesis of graphitic-N and amino-N in nitrogen-doped carbon via a solution plasma process and exploration of their synergic effect for advanced oxygen reduction reaction. Journal of Materials Chemistry A 2017, 5 (5), 2073-2082.Xie, B.; Zhang, Y.; Zhang, R., Coassembly and high ORR performance of monodisperse Pt nanocrystals with a mesopore-rich nitrogen-doped graphene aerogel. Journal of Materials Chemistry A 2017, 5 (33), 17544-17548 Figure 1

Green synthesis of Vitis vinifera extract-appended magnesium oxide NPs for biomedical applications

Abstract Biologically active magnesium oxide (MgO) nanoparticles were synthesised using green reduction with an extract derived from the Vitis vinifera plant. The investigation focused on examining the structure and carbon abundance resulting from the thermal degradation of adsorbed biomolecules. It was accomplished using powder X-ray diffraction, Raman spectroscopy, and FT-IR analysis techniques. X-ray photoelectron spectroscopy studies conducted on MgO nanoparticles indicate the absence of any supplementary peaks, thereby indicating the purity of the material. The morphological characteristics, which have been examined using field emission scanning electron microscopy and TEM methodologies, demonstrate the presence of particles with a spherical shape, exhibiting minimal agglomeration and a uniform distribution across the surfaces of MgO. The porous structure, porosity, and pore volume of the MgO particles were evaluated using Brunauer-Emmett-Teller surface analysis. The experimental findings reveal that the surface area of the MgO nanoparticles is 23.8742 m2/g, while the total pore volume is 0.12528 cm3/g. Additionally, the average pore diameter is determined to be 1.7 nm. These observations collectively suggest the presence of microporous structures within the MgO nanoparticles. This article discusses the biological studies to assess the antibacterial, antifungal, anti-inflammatory, and anti-diabetic activities of the synthesised MgO nanoparticles.

Microwave assisted synthesis of NiMn&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt; as electrode material for supercapacitor applications

In this work, spinel NiMn2O4 was successfully synthesized through microwave assisted co-precipitation method and followed by calcination at 500°C. The crystal structure and the presence of functional groups in NiMn2O4 were characterized through X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The surface morphology was examined by field emission scanning electron microscopy (FE SEM). From the BET analysis surface area and average pore diameter of the mesoporous NMO nanoparticles are calculated to be 10.513 m2g-1and 8.55nm. The electrochemical performance of material as electrode material for supercapacitor applications was analysed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The specific capacitance of the NMO electrode increased from 290.56 F/g to 751.57F/g with increase concentration from IM KOH to 6M KOH at scan rate of 5mV/s. These results indicate spinel NiMn2O4 as a promising candidate for high performance energy storage applications.

Enhancing photocatalytic dye degradation efficiency through the utilization of shock wave effects on neodymium oxide (Nd2O3)

This article delves into the impact of shockwaves on neodymium oxide (Nd2O3) nanoparticles, aiming to evaluate their physical and chemical stability. Nd2O3 nanoparticles were subjected to varying sets of shock pulses (100, 200, and 300) in photocatalytic dye degradation. The nanoparticles crystallinity and unit cell volume after shockwave exposure were examined using powder X-ray diffraction (PXRD) analysis with unit-cell software. PXRD data revealed no alterations in the crystalline structure, lattice parameter and unit cell volume. Comparisons between pre- and post-shockwave field emission scanning electron microscopy (FE-SEM) portraying data demonstrate that repeated shockwave application causes a decrease in particle size. Raman spectroscopy, under ambient conditions, shows a high intensity after shock conditions intensity will decrease. Furthermore, FTIR spectroscopy revealed the characteristic strong and broad absorption band associated with metal-oxygen (Nd-O) groups in the Nd2O3 nanoparticles. UV–Vis diffuse reflectance spectroscopy (DRS) was used to investigate the bandgap of the Nd2O3 nanoparticles. Initially, the bandgap was measured at 5.96 eV under ambient conditions, but following the shockwave exposure, it was decreased to approximately 5.91 eV. Interestingly, the surface area of the shockwave-treated Nd2O3 nanoparticles is increased and exhibited an increased efficiency in photocatalytic dye degradation. This finding holds promising implications for environmental remediation applications.

Preparation of Hollow Silica Nanoparticles with Polyacrylic Acid and Their Moisture Sorption Properties

Hollow silica nanoparticles (HSNPs) have hygroscopic properties because of their high specific surface area and surface hydroxyl groups. However, compared with other hygroscopic materials, their hygroscopic properties are relatively weak, which limits the further application of HSNPs. One feasible method to enhance their hygroscopic properties is by combining highly hygroscopic materials with hollow silica nanoparticles. To take advantage of the high hygroscopicity of polyacrylic acid (PAA) when combined with the high specific surface area of the hollow particles, PAA was coated on the inner and outer surfaces of the silica shell of the nanoparticles in this study to prepare hollow nanoparticles with a PAA/silica/PAA multilayer structure. The size of the PAA/silica/PAA multi-layer nanoparticles is about 85 nm, and the shell thickness is 25 nm. The specific surface area of the multi-layer nanoparticles is 58 m2/g. The water vapor adsorption capacity of multi-layer structure hollow nanoparticles was increased by 160% compared with the HSNPs (increased from 45.9 cm3/m2 to 109.1 cm3/m2). Meanwhile, at the same content of PAA, the PAA/silica/PAA-structured particles will adsorb 9% more water vapor than the PAA/silica-structured particles. This indicates that the high specific surface area structure of the hollow particles will enhance the adsorption ability of PAA toward water vapor. This novel structure of PAA-HSNPs is expected to be used as a humidity-regulating material for filler in environmental and architectural applications.

CVD based synthesis of binder free nanostructured MgS/MoS2@NiF electrode material for asymmetric supercapacitor applications

Two-dimensional molybdenum disulfide (MoS2) electrode materials (EMs) have gained significant interest due to their remarkable electrochemical performance in renewable energy storage devices (RESDs). However, the layered agglomeration decreases the EMs practical applications in RESDs. By combining with transition metal sulfide, layered agglomeration and electrochemical performance can be improved violently. Therefore, in this research work, MoS2-based magnesium sulfide (MgS/MoS2) nanostructured EMs are synthesized on nickel foam (NiF) via a chemical-vapor-deposition (CVD) technique. The synthesis of MoS2 and heterostructured MgS/MoS2@NiF EMs having cluster of nanoparticles and nanoneedles like microstructure is confirmed by field emission scanning electron microscopic analysis. The surface area (170 m2g-1) of nanoneedles based MgS/MoS2@NiF EMs is significantly higher than the surface area (60 m2g-1) of nanoparticles based MoS2@NiF EMs, causes to increase the electrocheomical performance of the syntehsized EMs. The MgS/MoS2@NiF EMs is preserved maximum specific capacitance of 9149 Fg-1 at 10 Ag-1, energy density of 234–171 Whkg-1, power density of 2150–4300 Wkg-1 and capacitance retention of 98.2 % for 10,000 cycles. The cyclic voltammetric study is indicated that the EMs have pseudocapacitive nature (diffusion process) which is increased by addition of MgS layer over MoS2 surface. The shifting of impedance profile to y-axis confirmed the increasing diffusion rate of ions in the pores of MoS2 by the addition of MgS layer. The theoretical Dunn's model also revealed that the over-all current produced by the synthesized EMs is due to the current contribution of diffusive and capacitive controlled process. The asymmetric supercapacitor (ASC) device preserved pseudocapacitive nature with maximum specific capacitance of 701 Fg-1 at 4 Ag-1. Moreover, the ASC device is presented the energy density ranged from 288 to 151 Whkg-1, power density ranged from 3440 to 21,500 Wkg-1, Coulombic efficiency of 100 % and capacitance retention of 95 % for 10,000 cycles performed at 20 Ag-1.

Development of High Surface Area Organosilicate Nanoparticulate Thin Films for Use in Sensing Hydrophobic Compounds in Sediment and Water.

The scope of this study was to apply advances in materials science, specifically the use of organosilicate nanoparticles as a high surface area platform for passive sampling of chemicals or pre-concentration for active sensing in multiple-phase complex environmental media. We have developed a novel nanoporous organosilicate (NPO) film as an extraction phase and proof of concept for application in adsorbing hydrophobic compounds in water and sediment. We characterized the NPO film properties and provided optimization for synthesis and coatings in order to apply the technology in environmental media. NPO films in this study had a very high surface area, up to 1325 m2/g due to the high level of mesoporosity in the film. The potential application of the NPO film as a sorbent phase for sensors or passive samplers was evaluated using a model hydrophobic chemical, polychlorinated biphenyls (PCB), in water and sediment. Sorption of PCB to this porous high surface area nanoparticle platform was highly correlated with the bioavailable fraction of PCB measured using whole sediment chemistry, porewater chemistry determined by solid-phase microextraction fiber methods, and the Lumbriculus variegatus bioaccumulation bioassay. The surface-modified NPO films in this study were found to highly sorb chemicals with a log octanol-water partition coefficient (Kow) greater than four; however, surface modification of these particles would be required for application to other chemicals.

Hierarchical core-shell electrode with rGO wrapped NiWO4 nanowire arrays on Ni foam for high-performance asymmetric supercapacitors

This paper presents a novel class of hierarchical core-shell nanowire arrays (NWAs) that may greatly enhance the electrochemical storage of energy capabilities of supercapacitors. These NWAs consist of rGO sheets surrounding a NiWO4 nanowire core. The average surface area of NiWO4 nanoparticles was 105.7 m2/g, and their sizes ranged from 20 to 100 nm. The NWO/rGO composite has an impressive specific capacitance of up to 1156 F g−1 at 1 A g−1 current density. The synergistic impact of NiWO4 and rGO, which offer conducting channels and active sites, is responsible for the NWO/rGO electrode's significantly improved capacitive performance. This hybrid electrode has a lot of promise for use in energy storage devices since the cyclic stability tests showed that its starting values did not decline after 5000 cycles. In a three-electrode system, the NiWO4/rGO electrode provides more energy density compared to the NiWO4 electrode because to a boost in specific capacitance and a wider potential window (1 V for nanocomposite NiWO4/rGO vs. 0.6 V for NiWO4). Electrodes made of a nanocomposite of NiWO4 and rGO are used to construct a symmetric capacitor. Both the asymmetric and symmetric capacitors function similarly when driven within a 1.5 V potential region. On top of that, the device achieved a power density of 932 W kg−1 and an energy density of 42 Wh kg−1.

Comparative investigation on physicochemical, biological, and cytotoxicity of magnesium oxide prepared by chemically mediated and green synthesis using the bark of Cassia absus Linn

The MgO nanoparticles were synthesized from the bark extract of Cassia absus Linn. and the chemical method. The green synthesized and chemically synthesized MgO nanoparticles were confirmed from the XRD and FTIR analysis. The green synthesized MgO showed reduced particle size and nanorods morphology whereas the chemically synthesized samples showed nanoflake morphology. The phenolic components present in the green synthesized MgO nanoparticles aided in the improved antioxidant properties and the improved surface area of MgO nanoparticles resulted in the slow and sustained drug release (10 % delay) which could be an attractive property in the delivery of the antibiotics. The sample is non-cytotoxic and the zebrafish embryo mortality rate is much lesser than that of the chemically synthesized MgO nanoparticles. The fibroblast viability was enhanced in the green synthesized MgO nanoparticles; therefore, the MgO nanoparticles could be used in drug delivery systems and tissue engineering applications.

P-doped Mo2C nanoparticles embedded on carbon nanofibers as an efficient electrocatalyst for Li-S batteries

Designing a reliable sulfur host that can simultaneously catalyze sulfur redox reactions and suppress polysulfides shuttling is highly desired for the development of advancing Li-S batteries. In this work, P-doped Mo2C nanoparticles anchoring on carbon nanofibers (CNF) is prepared via an organic–inorganic nanohybridization process. The interwoven CNF networks establish continuous electrons transport pathways and provide a large surface area for loading P-Mo2C nanoparticles. The P dopant tunes the electronic structure of Mo2C, which endows P-Mo2C with enhanced polysulfides adsorption ability and improved sulfur redox kinetics. Leveraging these advantages, the Li-S battery shows excellent electrochemical properties, delivering a high specific capacity of 1174 mA·h·g−1 at 0.2 C, and maintaining over 1200 stable cycles at 1 C with a low capacity attenuation rate of 0.043 % per cycle. At a S loading of 4.88 mg·cm−2 and E/S ratio of 8.25 μL·mg−1, the Li-S battery attains an areal capacity of 6.50 mA·h·cm−2 at 0.05 C. These results highlight the promising application potential of P-Mo2C@CNF as an effective electrocatalyst for Li-S batteries.