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Magnetic fine particle-insulator composite films containing Fe-Ni fine particles and insulating epoxy films used for electromagnetic (EM)-wave-absorbing films were synthesized by a newly developed electrochemical method termed the “layer-by-layer (LbL)-assisted composite plating method.” A reaction solution containing water-soluble epoxy resin and Fe-Ni fine particles was used for film fabrication. Cu substrates and Ti/Pt plates were used as the cathode and the anode, respectively. In LbL-assisted composite plating, the attraction of charged Fe-Ni fine particles to the cathode by electrostatic force and electrodeposition of insulating epoxy film occurred simultaneously. LbL treatment was performed using poly(sodium 4-styrenesulfonate) (PSS) solution and poly(diallyldimethylammonium chloride) (PDDA) solution to induce negative and positive surface charge of the Fe-Ni fine particles, respectively. It is found that LbL treatment is effective for increasing charging electrons on Fe-Ni fine particles and for enhancing their dispersibility in the reaction solution. Over 39 vol.% Fe-Ni particles contained in the epoxy films were successfully obtained by using the LbL-assisted composite plating method.

Metal–insulator composite films, including Fe–B ultrafine particles and insulating epoxy films, were synthesized by the layer-by-layer (LbL)-assisted composite plating method. In this method, charged magnetic ultrafine particles were attracted to the cathode by electrostatic force simultaneously with the deposition of insulating epoxy thin film. To suppress the oxidation of Fe–B ultrafine particles in the reaction aqueous solution for Fe–B/epoxy composite film deposition, Fe–B ultrafine particles were coated with epoxy by using the electroless plating method. It was clear that epoxy coating on Fe–B ultrafine particles effectively prevents oxidation. The film deposited using epoxy-coated Fe–B ultrafine particles exhibited a smoother film surface than those obtained using uncoated Fe–B ultrafine particles. However, the highest amount of Fe–B content obtained in the deposited film was approximately 36 vol.% using Fe–B ultrafine particles with a concentration of 1.0 g/L.

In this work, anodic oxidation of Ti-40 wt.% Zr alloy in EG/NH4F/H2O electrolyte was done to produce anodic self-aligned oxide nanotube arrays. The nanotubes were amorphous but upon annealing at 400° C they were crystallized into ZrO2–TiO2nanotubes and ZrTiO4–TiO2nanotubes at 600 °C. The nanotubes were used to reduce 60 ppm Cr(VI) ions under sunlight or UV irradiation. 100% removal of Cr(VI) was achieved on ZrTiO4–TiO2nanotubes after 5 h of exposure to UV light but only 53% removal was obtained on ZrO2–TiO2nanotubes. The higher photocatalytic activity of the ZrTiO4–TiO2nanotubes can be related to the presence of the ZrTiO4phase which has good acid–base properties as well as the junction formation between ZrTiO4and TiO2that can further enhance the reduction process.

Agriculture and industrial wastes (AIWs) have attracted much attention because of their huge environmental, economic, and social impacts. AIWs have been considered a crucial link of a closed-loop for the fabrication of nanomaterials and composites wherein they replace traditional resources with sustainable waste in waste management. In this context, the proper disposal of AIWs is required. This review aims to investigate the technical feasibility of using innovative AIW resources and various strategies for the fabrication of nanomaterials for improving energy applications. First, the utilization of AIWs is classified comprehensively. Second, key technologies to produce nanomaterials are summarized. In addition, this review discusses the potential applications of the fabricated nanomaterials in energy storage and energy conversion.

In this research work, we have applied a dry microwave (MW) strategy to synthesize uniformly sized CoO nanocrystals homogeneously dispersed on the basal plane of nitrogen-doped reduced graphene oxide nanosheets (N-rGO NSs). The MW treatment is an ultra-fast process for exfoliation and in-situ reduction of graphite oxide and simultaneous decomposition of the cobalt precursor. The results show that during the MW-assisted synthesis process, the graphite oxide is exfoliated, reduced and combined with the available nitrogen from the precursor to form N-rGO NSs. Simultaneously; the Co ions react with oxygen functionalities on surface of N-rGO NSs to form CoO (N-rGO@CoO) nanocrystals. These processes, when combined, effectively prevented the aggregation of the CoO nanocrystals and the re-stacking of the N-rGO layers. The resulting N-rGO@CoO nanocomposites exhibited unique surface morphology and electrochemical performance for supercapacitor (SC) applications. As the SC electrode, the nanocomposite delivered high specific capacitance (744.1 F/g at 5 mV/s) and excellent cyclic stability (91.3 % over 5000 cycles). Thus the MW-processing method proved to be a rapid, effective, and simple approach for single step synthesis of doped rGO-metal oxide electrodes for SC applications.

In this study, Co–Ni layered double hydroxide (LDH) nanosheets are synthesized on nickel foam (NF) using a simple, facile, and cost effective electrochemical deposition method. We present a comparative study of Co–Ni LDH nanosheets on NF for use in supercapacitor electrodes. The method is based on electrochemical deposition using cyclic voltammetry (CV) with different cycles (4, 6, 8, and 10 cycles). Compared to other cycles, the Co–Ni LDH nanosheets on NF as electrode materials obtained higher specific capacitance at eight cycles. In 1 M potassium hydroxide (KOH), a significant specific capacitance of 3130.8 F/g was obtained at a scan rate of 5 mV/s, with good cyclic stability of 72.4% capacitance retention after 3000 cycles. The uniform and porous structure of Co–Ni LDH nanosheets on NF and the fast ion transfer between the electrolyte–electrode interface and reduced resistance contribute to this superior electrochemical efficiency, confirmed by CV and electrochemical impedance (EIS) studies. Co–Ni LDH nanosheets on NF are promising candidates for low-cost high-efficiency energy storage electrode materials for supercapacitor applications because of their superior performance and ease of preparation.

Global overpopulation, industrial expansion, and urbanization have generated massive amounts of wastes. This is considered as a significant worldwide challenge that requires an urgent solution. Additionally, remarkable advances in the field of biomedicine have impacted the entire spectrum of healthcare and medicine. This has paved the way for further refining of the outcomes of biomedical strategies toward early detection and treatment of different diseases. Various nanomaterials (NMs) have been dedicated to different biomedical applications including drug delivery, vaccinations, imaging modalities, and biosensors. However, toxicity is still the main factor restricting their use. NMs recycled from different types of wastes present a pioneering approach to not only avoid hazardous effects on the environment, but to also implement circular economy practices, which are crucial to attain sustainable growth. Moreover, recycled NMs have been utilized as a safe, yet revolutionary alternative with outstanding potential for many biomedical applications. This review focuses on waste recycled NMs, their synthesis, properties, and their potential for multiple biomedical applications with special emphasis on their role in the early detection and control of multiple diseases. Their pivotal therapeutic actions as antimicrobial, anticancer, antioxidant nanodrugs, and vaccines will also be outlined. The ongoing advancements in the design of recycled NMs are expanding their diagnostic and therapeutic roles for diverse biomedical applications in the era of precision medicine.

•Microwave synthesis method is very fast, single-step and cost-effective.•Co3O4/CoO nanoparticles are covered by rGO nanosheets via microwave irradiation.•Hybrid materials show good specific capacitance with high cycling stability.•Reduction/exfoliation of graphite oxide provide high temperature.•Microwave reduction, exfoliation and metal oxide covering occurs at same time.

•Synthesis of Ni(OH)2-ErGO on 3D network nickel foam (NF) substrate by electrochemical deposition via two-steps process.•The synthesized Ni(OH)2-ErGO@NF was used as supercapacitors’ electrode with magnificent electrochemical performance.•Ni(OH)2-ErGO@NF showed very high specific capacitance of 3138 F/g at scan rate 20 mV/s.•The cyclic stability of Ni(OH)2-ErGO@NF exhibited long-term stability over 1000 cycles at scan rate 50 mV/s with capacitance retention 91.6%.•A provisional mechanism of Ni(OH)2-ErGO@NF formation was proposed in simple and easy steps.

Multiferroic nanocomposites which possess both ferroelectric and ferromagnetic properties are attracting much attention because of their scientific interest and significant technological promise in novel multifunctional devices. In this work, multiferroic nanocomposites are targeted by anodization of Ti sheets to get TiO2nanotubes followed by hydrothermal treatment to form BaTiO3nanotube arrays, which were then used as a component to fabricate multiferroic nanocomposites through electrophoretic deposition (EPD) of CoFe2O4 nanoparticles into the tubular pores. Successful formation of BaTiO3nanotube arrays and CoFe2O4 nanoparticles were achieved. The morphologies and crystal structure of BaTiO3nanotube arrays were analyzed by a scanning electron microscope (SEM) and an X-ray diffractometer (XRD). Simulation of EPD of CoFe2O4 nanoparticles into BaTiO3nanotube arrays was also performed in order to predict and improve the susceptibility of forming a desired composite layer.

In the search for sustainable alternative energy sources the dye-sensitized solar cell (DSSC) has proven a viable contender in photovoltaics with core advantages of facile and low-cost fabrication; and record cell power conversion efficiency (PCE) between 11–14%. This is competitively low; compared to that of the more common Si-based cells of 14–26%. Plasmonic DSSCs, with the potential of highly concentrating optical energy in cells from the localized surface plasmon resonance effect, were predicted to attain very high PCEs. However, the record plasmonic DSSC PCE is only 10.8%, attributed to, mainly, the secondary effects of plasmonic nanostructures not well understood yet. This study employed Ag@TiO2plasmonic nanowires (PNWs), a systematic approach, wide-range PNW loadings and extended characterization to study their effects on the performance of DSSCs. They enhanced PCE from 4.63% to 5.03% from a balance of the negative and positive effects of the PNWs; most uniquely via efficient charge transport. The PNWs exhibited electron-sink effect causing upward shift of the TiO2Fermi level with poor charge injection efficiency, at high concentrations. They improved charge collection and resistance against recombination. These results will serve as valuable guide in the field of plasmonic DSSCs and related fields.

We have developed sintered porous iron negative electrodes used for iron-based rechargeable batteries such as iron-air and nickel-iron batteries. The water-atomized iron powders having a diameter of a several tens micrometers were mixed with polyvinyl alcohol that acted as a pore former, and sintered at 1120 °C for 20 min in N2atmosphere. The iron electrodes were examined for iron-air batteries as well as three electrodes cell. Two distinct plateaus were observed in the discharge curve and the capacity of the iron air batteries exceeded 100 mAh/g(Fe). The proposed electrodes are promising for cost effective, highly safe, and environmental friendly rechargeable batteries.

The electrochemical performance of porously sintered iron-based negative electrodes was examined to assess their suitability for application to high performance alkaline rechargeable batteries. Atomized iron-based powders with and without sulfur were used as raw materials of the electrodes. In order to clarify the discharge-charge mechanism, effects of additives such as K2S, Bi2S3and LiOH on the electrochemical reaction were also discussed based on the results of cyclic voltammetry in conjunction with changes in the chemical bonds along with the depth from the electrode surface. It was found that the electrochemical performance of the iron electrodes (atomized iron-based powders without sulfur) was improved when K2S was added to the electrolyte of 8 M KOH. The discharge capacity was two times larger than those having the LiOH or Bi2S3additive in the electrolytes. Furthermore, the discharge curves showed three distinct potential plateaus at about −1.0, −0.9 and −0.7 V vs. Hg/HgO, indicating that oxidation reaction was induced by sulfur additive in the electrolyte. It was revealed by X-ray photoelectron spectroscopy (XPS) analysis that the surface of the iron was uniformly covered with FeS of about 200 nm in thickness in the vicinity of the electrode surface. It is obvious from the XPS spectra that formation of FeS was the primary reaction on the electrode surfaces. Owing to the above-mentioned reaction, the discharge capacity for the negative electrodes fabricated with the sulfur-containing iron-based atomized powders increased with the number of cycles and reached 200 mAhg−1(Fe) at the 15th cycle, and maintained the behavior up to 25 cycles with a Coulombic efficiency of around 100%.