Preparation Of Nanocomposites Research Articles

Investigation on mechanical, electrical and morphological of high-density polyethylene (HDPE) reinforced with different particle size and composition of graphene nanoplatelets (GNP)

Graphene nanoplatelets (GNP) are just one of the attractive graphene-based nanomaterials that are rapidly emerging and have sparked the interest of many industries. These small stacks of platelet-shaped graphene sheets have a unique size and morphology that quickly disperse into other materials such as polymers, resulting in higher-value composite materials with improved thermal, conductivity, and mechanical capabilities. A detailed analysis of reinforced High-Density Polyethylene (HDPE) using different sizes (2, 15, 25 µm) and compositions (8, 10, 15 wt.%) of Graphene Nanoplatelets (GNP) has been conducted. The microstructure of the HDPE/GNP nanocomposites was extensively examined during the melt blending and injection moulding processes. Based on the results, the nanocomposites with different sizes of GNP exhibited dissimilar behaviour with different compositions. Furthermore, scanning electron microscope (SEM) results indicated a homogeneous dispersion for GNP in melt mixing. Moreover, thermogravimetric (TG) data demonstrate that increasing filler showed a slight increase in the material's thermal stability. The use of GNP improved mechanical properties, as evidenced by the increases in Young's modulus of yield strength from around 100 MPa to over 400 MPa. This study provides a practical reference for the industrial preparation of polymer-based graphene nanocomposites.

Preparation of a silver ferrite-assisted tungsten oxide nanocomposite for efficient sonocatalytic degradation of organic pollutants activated by PMS followed by toxicity evaluation

Sonocatalytic technology combined with ultrasonic irradiation with semiconductor catalyst has attracted much attention to address environmental issues.

Preparation of carbon nanotube-reinforced polyethylene nanocomposites with better anti-scaling and corrosion-resistant properties

Carbon nanotube-reinforced polyethylene nanocomposites have been prepared and show good anti-scaling and corrosion-resistant properties.

Recent advancements in the specific determination of carcinoembryonic antigens using MOF-based immunosensors.

Carcinoembryonic antigens (CEAs) are prominent cancer biomarkers that enable the early detection of numerous cancers. For effective CEA screening, rapid, portable, efficient, and sensitive diagnosis approaches should be devised. Metal-organic frameworks (MOFs) are porous crystalline materials that have received major attention for application in high-efficiency signal probes owing to their advantages such as large specific surface area, superior chemical stability and tunability, high porosity, easy surface functional modification, and adjustable size and morphology. Immunoassay strategies using antigen-antibody specific interaction are one of the imperative means for rapid and accurate measurement of target molecules in biochemical fields. The emerging MOFs and their nanocomposites are synthesized with excellent features, providing promising potential for immunoassays. This article outlines the recent breakthroughs in the synthesis approaches of MOFs and overall functionalization mechanisms of MOFs with antigen/antibody and their uses in the CEA immunoassays, which operate according to electrochemical, electrochemiluminescent and colorimetric techniques. The prospects and limitations of the preparation and immunoassay applications of MOF-derived hybrid nanocomposites are also discussed at the end.

Highly dispersed noble metal nanoparticle composites on biomass-derived carbon-based carriers: synthesis, characterization, and catalytic applications.

Precious metal nanoparticles have been widely investigated due to their excellent activity shown in catalysis and sensing. However, how to prepare highly dispersed noble metal nanoparticles to improve the lifetime of catalysts and reduce the cost is still an urgent problem to be solved. In this study, a carbon-based carrier material was prepared by an expansion method and loaded with Pd or Ag nanoparticles on this carbon material to synthesize precious metal nanoparticle composites, which were characterized in detail. The results show that the nanoparticles prepared using this method exhibit superior dispersion. Under the synergistic effect of noble metal nanoparticles and porous carbon carriers, the composites exhibited excellent catalytic degradation of p-nitrophenol and showed excellent sensing performance in the modified hydrogen peroxide sensor electrode. This approach is highly informative for the preparation of nanocomposites in medical and environmental fields.

Facile preparation of mesoporous NiS-coupled Co3O4 nanocomposites for photocatalytic reduction of Cr(VI) ions under visible light illumination

Cr(VI) ion deposits in water can negatively affect the ecosystem and people's health. Constructing a reusable and effective photocatalyst defies dominating semiconductors' unstable nature and rapid recombination. Here, with variable NiS contents, new sol-gel nanocomposites of mesoporous NiS–Co3O4 were synthesized. We investigated the photocatalytic performance of NiS nanoparticles (NPs) anchored to mesoporous Co3O4 in the photoreduction of Cr(VI) ions under visible illumination. The structural, textural, and optical features of the synthesized materials were completely characterized by different techniques. The constructed nanocomposites demonstrated mesostructured materials with 133–160 m2/g of surface area. Changing the NiS content revealed the diminution in bandgap (Eg) from 2.46 to 1.8 eV and hence Co3O4's ability to absorb visible light was altered. The 2.0 gL-1 of 12 wt% NiS–Co3O4 photocatalyst demonstrated superior photoreduction efficiency of Cr(VI) ions with a photoreaction rate of 0.0583 min−1 after 50 min of illumination. Moreover, this photocatalyst revealed effective photocatalytic stability and retained 97 % of its original performance after 5 cycles. The enhancement in performance of this NiS–Co3O4 nanocomposite is mainly due to modified light absorption and potent interfacial isolation of charge carriers.

Evaluation of the antibacterial properties of copper-based mixed metal oxide nanocomposite

Copper-based nanocomposite has a wide variety of applications in various fields of science. The present study focuses on the preparation of copper oxide and zinc oxide nanocomposites by the chemical precipitation method. The prepared samples were analyzed with the help of various characterization techniques, such as XRD, SEM, UV/visible spectroscopy, and EDAX. Using the XRD pattern, the crystallite size determination is carried out, and the crystalline nature of the nanocomposite is confirmed. With SEM analysis, surface morphological studies were performed. EDAX analysis conforms to the formation of mixed metal oxide nanocomposites. The antimicrobial behavior of samples was evaluated for E. coli bacteria using the disc diffusion method.

Preparation of novel and recyclable chitosan-alumina nanocomposite as superabsorbent to remove diazinon and tetracycline contaminants from aqueous solution

This work presents a novel, strong and efficient adsorbent (CS@TDI@EDTA@γ-AlO(OH)) prepared through the green process using three components, chitosan, BNPs and EDTA using amide and ester bridges. An eco-friendly and easy approach was used for the preparation of this novel adsorbent, the low cost, easy access to the used materials, and the simplicity of the preparation method are some of the interesting advantages of this work. Also, this prepared adsorbent was used as an adsorbent to remove diazinon organophosphate poison and tetracycline antibiotic from aqueous solutions. In order to confirm the prepared adsorbent structure, the CS@TDI@EDTA@γ-AlO(OH) composite was investigated by various analyses including FT-IR, EDX, XRD, FESEM and TGA. The adsorption behavior of the adsorbent prepared for the removal of tetracycline and diazinon was investigated under different conditions by varying the concentration, temperature, the adsorbent dose, pH and contact time. Based on various tests, the highest diazinon adsorption capacity was obtained for 0.12 g/L adsorbent at pH 7 and 60 °C with 40 mg/L initial concentration. Also, the maximum adsorption capacity of the tetracycline was obtained for 0.12 g/L adsorbent at pH 9 and 60 °C with 30 mg/L initial concentration. The equilibrium results for diazinon and for tetracycline were in good accordance with the Langmuir and Freundlich isotherm models, respectively. Also, the highest adsorption capacities for diazinon at pH 7 and tetracycline at pH 9 were 1428.5 and 555.5 mg/g, respectively. Also the kinetic investigations revealed that the correlation factor (R2) of pseudo-second-order model obtained for the adsorption of diazinon and tetracycline was 0.9986 and 0.9988, while the coefficient k (g/mg.min) was 0.000084 and 0.0033, respectively. These results indicate that the adsorption of diazinon and tetracycline is pseudo-second-order kinetics model. Formation of hydrogen bonds between adsorbate and adsorbent as well as the high specific surface area and porosity of the adsorbent are the main mechanisms that contribute to the adsorption process. In addition, thermodynamic studies indicated that the adsorption of diazinon and tetracycline is a spontaneous endothermic process. The adsorbent prepared in this work was expected to have wide range of applications in wastewater treatment thanks to its good reusability in water and strong removal of diazinon and tetracycline compared to other adsorbents.

A flexible capacity-metric creatinine sensor based on polygon-shape polyvinylpyrrolidone/CuO and Fe2O3 NRDs electrodeposited on three-dimensional TiO2–V2O5–Polypyrrole nanocomposite

The innovations of the present work include these items; (i) Design and preparation of three-dimensional flexible conductive polymeric nanocomposites (3D-FCPNCs) containing polypyrrole (PPy), V2O5 and TiO2 and modification of their surface with polygon-shape polyvinylpyrrolidone/CuO nanorods (PVP/CuO NRDs) and Fe2O3 NRDs using an hierarchical process based on isoelectric point (IEP), (ii) Application of the prepared surfaces as the flexible enzymeless creatinine sensors using four calibration curves (impedimetric, real capacitance (C′), imaginary capacitance (C″) and double layer capacitance (Cdl)) obtained from electrochemical impedance spectroscopy (EIS) technique. The best results have been obtained using PVP/CuO NRDs–Fe2O3 NRDs/TiO2–V2O5–PPy 3D-FCPNC hierarchical electrode with a wide range of the linear concentration range (10 nmol L−1 −1.3 mmol L−1). Although, determination of creatinine through extraction of parameters such as charge transfer resistance (Rct) and Cdl from measuring impedance at a wide range of frequencies provides useful information about the characteristics of the electrolyte/electrode interface, but measuring real and imaginary capacitances at a specific frequency instead of a wide frequency range can decrease the response time to lower than 1 min. Finally, the prepared hierarchical enzymeless sensors have been successfully used to estimate creatinine concentration in blood serum.

Epoxy-Encapsulated ZnO-MWCNT Hybrid Nanocomposites with Enhanced Thermoelectric Performance for Low-Grade Heat-to-Power Conversion.

This work is devoted to the development of epoxy-encapsulated zinc oxide-multiwalled carbon nanotubes (ZnO-MWCNT) hybrid nanostructured composites and the investigation of their thermoelectric performance in relation to the content of MWCNTs in the composite. For the preparation of nanocomposites, self-assembling Zn nanostructured networks were coated with a layer of dispersed MWCNTs and subjected to thermal oxidation. The resulting ZnO-MWCNT hybrid nanostructured networks were encapsulated in commercially available epoxy adhesive. It was found that encapsulation of ZnO-MWCNT hybrid networks in epoxy adhesive resulted in a simultaneous decrease in their electrical resistance by a factor of 20-60 and an increase in the Seebeck coefficient by a factor of 3-15, depending on the MWCNT content. As a result, the thermoelectric power factor of the epoxy-encapsulated ZnO-MWCNTs hybrid networks exceeded that of non-encapsulated networks by more than 3-4 orders of magnitude. This effect was attributed to the ZnO-epoxy interface's unique properties and to the MWCNTs' contribution. The processes underlying such a significant improvement of the properties of ZnO-MWCNT hybrid nanostructured networks after encapsulation in epoxy adhesive are discussed. In addition, a two-leg thermoelectric generator composed of epoxy-encapsulated ZnO-MWCNT hybrid nanocomposite as n-type leg and polydimethylsiloxane-encapsulated CuO-MWCNT hybrid nanocomposite as p-type leg characterized at room temperatures showed better performance at temperature difference 30 °C compared with the similar devices, thus proving the potential of the developed nanocomposites for applications in domestic waste heat conversion devices.

Design and preparation of ternary polymer nanocomposites for high energy density film capacitors

High discharge energy density (Ue) film capacitors are important for miniaturization and integration in power electronic applications. The Ue of a polymer film is mainly dependent on Weibull's breakdown strength (Eb) and dielectric constant (εr). This work aims to develop ternary nanocomposites composed of polycarbonate (PC), Al2O3 nanoparticles (Al2O3 NPs) and BaTiO3 nanowires (BT NWs) for capacitive energy-storage. Al2O3 NPs have a wide bandgap and are expected to enhance Eb owing to their insulating nature, while BaTiO3 nanowires (BT NWs) are ferroelectric and are expected to provide a high εr. To overcome local electric-field distortion at the interface due to the mismatch in εr, core-shell structured BT@SiO2 NWs are prepared. The Eb of the composite containing 1.0 wt% Al2O3 NPs and 6.0 wt% BT@SiO2 NWs can reach 626 MV/m while that of the pure PC is 465 MV/m. As a result, its Ue reaches 12.12 J/cm3, which is improved by 211% that of the pure PC. Its discharge efficiency is 83.5%. A finite element analysis corroborates the superiority of the ternary polymer nanocomposites for dielectric energy-storage.

Thermally induced Fe2O3 spikes decorated Ag/Fe2O3 nanocomposite fabrication for anti-bacterial and anti-cancer activities

In the context of anti-cellular catalytic permutations, the development of thermally-induced nanotechnology is of great importance. In this study, iron oxides (Fe2O3) decorated silver (Ag) core–shell nanocomposite was prepared using a green thermal decomposition process without using any additional chemicals. The nanocomposite was characterized for its composition, phase interactions, morphology, and stability using spectroscopic, thermogravimetric, and microscopic techniques. The resultant nanocomposite were also investigated against different types of bacteria and cancer cell lines. Both Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Klebsiella spp., E. coli, and Pseudomonas) growth was inhibited by the Ag/Fe2O3 nanocomposite. The highest 19 mm zone of inhibition (ZOI) was found for Staphylococcus aureus by the combined effect of Ag and Fe2O3. The antibiofilm efficacy of the prepared nanocomposites showed biofilm destruction of 82.56% Staphylococcus aureus and 51.06% Klebsiella spp. Furthermore, the nanocomposite resulted in 80–90% death of Hela and BHK-21 cells but displayed lower cell toxicity in the case of the Vero cell line. This pathway of nanocomposites preparation with particle surface engineering would open new doors in the fields of nanobiotechnology and nanobiomedical applications.

Preparation of the graphene-based smart hydrophobic nanocomposite and its application in oil/water separation.

Designing and synthesizing materials with smart hydrophobicity against an external magnetic field for efficient oil/water separation is of great importance due to the increasing problems caused by oil pollution. Here,the nanocomposites were fabricatedbased on graphene and different iron oxides exhibit smart hydrophobicity against an external magnetic fieldand they arein powder form eliminating the requirementfor a substrate employing a facile and echofriendly method. The results prove that autoclaving of graphene leads to its ferromagnetic property; then it is attached to iron oxides by magnetic attraction and a nanocomposite is produced. The magnetic property of the resulting nanocomposite is higher than the magnetic property of its individual components. In addition, following nanocomposite formation, its hydrophobicity and surface area also change. FESEM images were taken from the nanocomposites to study their surface morphology, and EDS-MAP analysis to observe the elemental distribution uniformity of the nanocomposites. Also, to measure the surface area and pore size, BET analysis has been performed on pure materials and graphene-black iron oxide nanocomposite (graphene@black iron oxide). The results show that the specific surface area of black iron oxide increases after being composited with graphene dispersed at 5000rpm. Indeed, graphene forms a composite by binding to iron oxide, and therefore, its specific surface area increases compared to iron oxide and graphene alone. These results show an increase in oil sorption and better separation of oil from water by the prepared nanocomposite. Also, to measure the magnetic properties of pure materials, graphene@black iron oxide, and ferromagnetic graphene at 3000 and 5000rpm, the Vibrating Sample Magnetometeranalysis has been performed. The results have proven that the nanocomposite powder prepared by a simple method obtained from cost-effective and available materials is hydrophobic and becomes more hydrophobic by applying an external magnetic field. Due to the ease with which oil can be readily removed from the nanocomposite by eliminating the external magnetic field, this nanocomposite is an excellent choice for the separation of oil from water.

Facile Fabrication of Energetic Nanocomposite Materials by Polydopamine.

Polydopamine-based materials have been widely investigated for incorporation in energetic nanocomposites due to their outstanding adherence. However, these materials are often prepared in alkaline environments, which negatively affects Al nanoparticles. In this study, a one-pot assembly was devised for the preparation of a polydopamine-based Al/CuO energetic nanocomposite material (Al/PDA/CuO) in a neutral environment. The CuO and Al nanoparticles of the Al/PDA/CuO nanothermite were uniformly dispersed and closely combined. Consequently, the Al/PDA/CuO nanothermite was able to release more heat (2069.7 J/g) than physically mixed Al/CuO (1438.9 J/g). Furthermore, the universality of using polydopamine in the assembly of different types of energetic nanocomposite materials was verified, including an organic energetic material-nanothermit (HMX/PDA/Al/CuO nanothermite) and an inorganic oxidant-metal nanocatalyst (AP/PDA/Fe2O3). This study provides a promising route for the preparation of polydopamine-based energetic nanocomposites in neutral aqueous solutions.

Ablation resistance of ZrC coating modified by polymer-derived SiHfOC ceramic microspheres at ultrahigh temperature

Polymer-derived ceramics (PDCs) method opens up new possibilities for the preparation of novel multiphase ceramic nanocomposites owing to the molecular design of the precursors at the nanoscale level. In the current work, ZrC coatings incorporated with polymer-derived ceramic microspheres (CMS), SiHfOC_CMS, were deposited to enhance the ablation resistance by supersonic atmosphere plasma spraying. Upon 10.0 MW·m–2 plasma ablation at above 3000 °C, the linear ablation rate of ZrC-SiHfOC_CMS coating was reduced to 0.20 µm·s–1, 62% lower than that of the pristine ZrC coating. The improvement was ascribed to the presentence of viscous SiO2/HfO2 molten mixed phase, rather than HfSiO4, which can effectively seal pinholes and cracks. Moreover, the in-situ generated crystalline SiO2 had a lower oxygen diffusion rate than amorphous SiO2, meanwhile, m-HfO2 could improve the stability of SiO2 glassy film, thus further enhancing the ablation resistance.

Synthesis and characterization of magnetic Ag–Fe3O4@polymer hybrid nanocomposite systems with promising antibacterial application

Introduction Bacterial infections caused by different strains of bacteria still one of the most important disorders affecting humans worldwide. Polymers nanocomposite systems could be considered as an alternative to conventional antibiotics to eradicate bacterial infections. Significance In an attempt to enhance the antibacterial performance of silver and iron oxide nanoparticles, decrease their aggregation and toxicity, a polymeric hybrid nanocomposite system combining both nanoparticles is produced. Methods Magnetic Ag–Fe3O4@polymer hybrid nanocomposites prepared using different polymers, namely polyethylene glycol 4000, ethyl cellulose, and chitosan were synthesized via wet impregnation and ball-milling techniques. The produced nanocomposites were tested for their physical properties and antibacterial activities. Results XRD, FT-IR, VSM, and TEM results confirmed the successful preparation of hybrid nanocomposites. Hybrid nanocomposites have average crystallite sizes in the following order Ag–Fe3O4@CS (8.9 nm) < Ag–Fe3O4@EC (9.0 nm) < Ag–Fe3O4@PEG4000 (9.4 nm) and active surface area of this trend Ag–Fe3O4@CS (130.4 m2g−1) > Ag–Fe3O4@EC (128.9 m2g−1) > Ag–Fe3O4@PEG4000 (123.4 m2g−1). In addition, they have a saturation magnetization in this order: Ag–Fe3O4@PEG4000 (44.82 emu/g) > Ag–Fe3O4@EC (40.14 emu/g) > Ag–Fe3O4@CS (22.90 emu/g). Hybrid nanocomposites have a pronounced antibacterial action against Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus intermedius compared to iron oxide nanoparticles and positive antibacterial drug. In addition, both Ag–Fe3O4@EC and Ag–Fe3O4@CS have a lower MIC values compared to Ag–Fe3O4@PEG and positive control. Conclusion Magnetic Ag–Fe3O4 hybrid nanocomposites could be promising antibacterial nanomaterials and could pave the way for the development of new materials with even more unique properties and applications.

Dispersion of silica nanoparticles in water/ethanol/PEG mixtures for stimuli-responsive aggregation to prepare improved fused silica glass

The preparation of bulk-fused silica glass using stimuli-responsive silica nanoparticle (SiNP) aggregation methods is a promising research topic. For instance, the use of a SiNP/polyethylene glycol (PEG)/polyvinyl butyral (PVB) system for thermoplastic nanocomposite preparation, followed by heat-treatment sintering, has emerged as a highly precise and scalable method for obtaining fused silica glass with a short processing time. In this study, transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and rheological analysis were used to investigate the dispersion of SiNPs in water, ethanol, water/ethanol, and water/ethanol/PEG mixtures. Furthermore, we investigated the effect of the different solvents on regulating external stimuli in the preparation of a SiNP slurry. Our results indicate that water/ethanol mixtures have a greater ability to obtain dispersed and thin slurries than water or ethanol alone, while the inclusion of PEG can further enhance this effect.The feedstocks obtained by this method is favorable for obtaining defect-free fused silica glass. In addition, agglomerates formed by SiNPs in a liquid environment can be rearranged and partially disassembled under the action of mechanical (shear) forces. Finally, optical profilometry tests showed that the sintered fused silica glass exhibited good surface quality replication, with a roughness Sa of only 148 nm. The finding in this study provides an idea for the preparation of commercial slurry for sintering fused silica glass.

Ultra-small Ni@NiFe2O4/TiO2 magnetic nanocomposites activated peroxymonosulphate for solar light-driven photocatalytic mineralization of Simazine

In the heterogeneous photocatalytic degradation of environmental contaminants the recovery, reuse of employed nanocatalyst was crucial and it is essentially required for the scale up applications. Besides, designing a magnetic material with heterojunction that can effectively oxidize the toxic organic contaminants to non-toxic substance under different reaction conditions including direct solar light irradiation remains a challenge. Considering the above facts, herein, we tailored heterojunction between the magnetic materials and non-magnetic materials with ultra-small Ni nanoparticles modified NiFe2O4/TiO2 nanostructures (Ni@NiFe2O4/TiO2 magnetic nanocomposites) through a simple sonochemical route. The Raman phonons at ∼ 540 cm−1 consistent to nickel metal nanoparticles and the spinel ferrites crystal structure confirmed the formation of Ni@NiFe2O4/TiO2 magnetic nanocomposites. The reduced optical bandgap of the resulting nanocomposites indicated the effective absorption of direct solar light irradiation when compared to the bare TiO2. Thus in-turn, enhanced the photocatalytic efficiency of simazine degradation in the presence of Ni@NiFe2O4/TiO2 magnetic nanocomposites (k´= 11.0 × 10–4 s−1) and augmented the activation of peroxymonosulphate (PMS) in the presence of Ni@NiFe2O4/TiO2 magnetic nanocomposites (k´= 32.5 × 10–4 s−1). Ni@NiFe2O4/TiO2 +PMS exhibited 3 folds enhanced efficiency in the presence of sunlight. The as-prepared NiFe2O4/TiO2 magnetic nanocatalysts were more stable and the efficiency of simazine oxidation was approximately same for the continuous five cycles at the optimized experimental conditions. The Ni@NiFe2O4/TiO2 magnetic nanocomposites preparation and the activation of PMS may promise the applications in an efficient wastewater treatment.

Preparation and characterization of a novel nanocomposite based on MnCr-layered double oxide and CoFe2O4 spinel ferrite for methyl orange adsorption

Herein, the adsorption of methyl orange (MO), a dangerous anionic dye, from an aqueous solution was investigated using a novel magnetic nanocomposite adsorbent. A nanocomposite entitled manganese chromium-layered double oxide/cobalt spinel ferrite, (MnCr)-LDO5wt.%/CoFe2O4, which links the interlayer structural characteristics of layered double oxides (LDOs) with the magnetic properties of spinel ferrites (SFs) was synthesized using the eco-friendly co-precipitation technique. Determination of structural parameters, crystallite size, and micro-strain was done using X-ray diffraction (XRD) analysis. Transmission electron microscopy (TEM) was used to determine grain shape and size. Surface analysis was performed using X-ray photoelectron spectroscopy (XPS) to identify elements and oxidation states present in the prepared nanocomposite. Vibrating sample magnetometer (VSM) was utilized to examine the magnetic characteristic. A comprehensive comparative study about the effectiveness and durability of CoFe2O4 and (MnCr)5wt.%/CoFe2O4 as nanoadsorbents for MO was conducted. Numerous variables, including contact time, MO concentration, adsorbent dosage, and pH were tested for their effects on the adsorption removal percentages. The findings showed that the maximum removal percentage was 86.1% for 25 ppm of MO was for 0.1 g/100 mL of (MnCr)-LDO5wt.%/CoFe2O4 at pH = 3. Investigations of isotherms and kinetics were conducted under batch conditions. The Langmuir isotherm matched the experimental data, for both nanoadsorbents, quite well due to the homogeneous distribution of active sites. Adsorption kinetics data were found to be compatible with intra-particle diffusion and pseudo-second order models for CoFe2O4 and (MnCr)5wt.%/CoFe2O4, respectively. A total of five adsorption–desorption cycles were performed to determine the prepared adsorbents’ recyclable nature.

Ultrafast synthesis of amorphous molybdenum sulfide by magnetic induction heating for hydrogen evolution reaction

Molybdenum sulfides have emerged as viable alternatives to noble-metal catalysts for green hydrogen production via the hydrogen evolution reaction (HER). Herein, magnetic induction heating (MIH) is exploited for the rapid preparation of carbon-supported MoSx nanocomposites. The sample prepared at 200 A for 10 s shows an amorphous Mo3S7Cly-like structure and a low overpotential (η10) of −184 mV at 10 mA cm−2 in acidic media, whereas samples prepared at higher induction currents display a largely crystalline MoS2 structure and drastically lower HER performance. This is due to the formation of dimeric Mo6S14 moieties in amorphous MoSx that is facilitated by the loss of Cl residues during electrochemical reaction and enhanced H adsorption at both the S and Mo sites, in comparison to crystalline MoS2, as shown in First-principles calculations. These results show that MIH may be used as a powerful tool in the preparation of nonequilibrium structures as high-performance electrocatalysts.