To improve the corrosion resistance and to increase the hardness of copper substrate in marine environment, the Cu-Ni/Ni-P composite coatings were prepared on the copper substrate using the galvanostatic electrolytic deposition method. The deposition current densities were explored to find the optimized deposition conditions for forming the composite coatings. Corrosion resistance properties were analyzed using the polarization curves and electrochemical impedance spectroscopy (EIS). Considering the corrosion resistance and hardness, the −20 mA/cm2 was selected to deposit Cu-Ni coatings on copper substrate and the −30 mA/cm2 was selected to deposit Ni-P coating on the Cu-Ni layer. The Cu-Ni/Ni-P composite coatings not only exhibited superior corrosion resistance compared to single Cu-Ni coating in 3.5 wt.% NaCl solution, but also showed much better mechanical properties than single Cu-Ni coating.

Three-dimensional graphene (3D-GN)/Cu/Fe3O4 composite support materials were synthesized by a modified chemical reduction method using graphene oxide precursor. A 3D-GN/Cu/Fe3O4 biosensor was prepared by coating the electrode with laccase. The electrochemical properties of the biosensor were investigated by cyclic voltammetry (CV) and differential pulse voltammetry using potassium ferricyanide, phosphate-buffered saline (PBS) solution, and bisphenol A (BPA) solution. The current response of 3D-GN/Cu/Fe3O4 biosensors presents a remarkable sensitivity based on CV. The linear range of BPA is 7.2–18 μM using differential pulse voltammetry in PBS solution (pH = 4.0). A linear fitting equation of the laccase biosensor was observed for the current response as a function of BPA concentration. The detection limit was decreased to 1.7 μM. The detection approach herein turns out to be highly sensitive, has a wide linear range, and exhibits excellent stability.

Wire-shaped supercapacitors (WSSCs) hold great promise in portable and wearable electronics. Herein, a novel kind of high-performance coaxial WSSCs has been demonstrated and realized by scrolling porous carbon dodecahedrons/Al foil film electrode on vertical FeOOH nanosheets wrapping carbon fiber tows (FeOOH NSs/CFTs) yarn electrode. Remarkably, ionogel is utilized as solid-state electrolyte and exhibits a high thermal/electrochemical stability, which effectively ensures the great reliability and high operating voltage of coaxial WSSCs. Benefiting from the intriguing configuration, the coaxial WSSCs with superior flexibility act as efficient energy storage devices and exhibit low resistance, high volumetric energy density (3.2 mW h/cm3), and strong durability (82% after 10,000 cycles). Importantly, the coaxial WSSCs can be effectively recharged by harvesting sustainable wind source and repeatedly supply power to the lamp without a decline of electrochemical performance. Considering the facile fabrication technology with an outstanding performance, this work has paved the way for the integration of sustainable energy harvesting and wearable energy storage units.

Biochar conversion from corn stover was evaluated under various process conditions, and the absorption capacity of biochar was investigated for the removal of oxytetracycline in wastewater. Biochar was prepared at lower carbonization temperatures (200–500 °C) and was used in three different concentrations of chemical oxygen wastewater. The results showed that the biochar prepared at the temperature range of 200–500 °C had a faster sorption rate and shorter sorption equilibrium time compared to biochar produced at higher temperatures. The longest time to reach sorption equilibrium was 9 h for biochar obtained at 200 °C. However, the biochar prepared at 500 °C required only 0.5 h to reach the sorption equilibrium. The corn stover-biochar had the highest sorption capacity of 246.3 mg/g for oxytetracycline at 30 °C. The adsorption kinetics was consistent with pseudo–second-order kinetics. This study provides a theoretical basis for the conversion of corn stover into biochar as efficient sorbents.

Single-crystal-like TiO2 is claimed to be a very promising material among various catalysts. In this study, the (N,F)-co-doped single-crystal-like TiO2 was prepared by a new molten mixing process in which the mixed nitrates were used both as a morphology modifier and an N-doping agent at the same time. The prepared samples also had well-developed (001) facet due to the addition of HF. The HF can also be an F doping agent to the material. The co-doping of N and F can diminish the band gap of TiO2 from 3.05 to 2.93 eV, therefore visible light can be used effectively by the material. In addition, NO and fluorine ions existing on the surface of the sample can also help its photocatalyticity. Therefore, the photocatalytic performance of the as-prepared sample was effectively improved.

Polyaniline nanofibers (PANI-NFs)/graphite oxide (GO) nanocomposites with excellent interfacial interaction and elongated fiber structures were synthesized via a facile interfacial polymerization method. This method efficiently exfoliated the expanded layer structure of GO into individual sheet and thus significantly enhanced the specific surface area. The reduced diameter of PANI-NFs in PANI-NF/GO than that of pure PANI-NFs could shorten the diffusion distance and enhance the electro-active sites. The PANI-NFs/GO hybrid materials showed orders of magnitude enhancement in capacitance and better cycling stability than that of individual GO and PANI-NF components.

Magnetic polyolefin-based nanocomposites were fabricated through a facile one-pot thermal decomposition of organo-metallic precursor, i.e. Fe(CO)5 in polymer-solvent solution condition. The whole fabrication includes dissolution of polyolefin-based hosting matrix in refluxing organic solvent followed by the injection of metallic precursor to perform the in-situ thermal decomposition step. The particle sizes, morphology and dispersion quality of these in-situ synthesized magnetic nanoparticles were investigated by transmission electron microscopy (TEM). Room temperature mössbauer spectrum analysis was used to determine the species of these magnetic nanoparticles. Room temperature magnetic property investigation was utilized to further reveal the magnetic behaviors of these nanocomposites by specifying the saturation magnetization and coercive forces. Thermal gravimetric analysis (TGA) was used to determine the thermal stability of these as-prepared nanocomposites and the particle loadings. The formation mechanisms of these magnetic particles were proposed from the evidence of TEM observations and detailed evolutions are detailed as well.

Polypropylene(PP)/Fe2O3 nanocomposites are fabricated using an in-situ method to uniformly disperse the magnetic nanoparticles (NPs) in polymer matrix. Maleic anhydride functionalized PP (f-PP) with different molecular weight is used as surfactant to stabilize the in-situ produced nanoparticles. The thermal behavior of PP and its nanocomposites with the incorporation of small amount f-PP is studied with thermal gravimetric analysis (TGA). The results show that the onset degradation temperature is increased by ~117 oC with the addition of NPs. Both melt rheology and transmission electron microscopy are used to investigate the NPs dispersion. Strong saturated magnetization (Ms) is observed after introducing f-PP to the nanocomposites through protecting the as-formed NPs from oxidation.

The manufacturing of magnetic PAN/Fe3O4 nanocomposite fibers is explored by an electrospinning process. The nanocomposite fibers were characterized by scanning electron microscopy (SEM). The magnetic properties of the nanoparticles in the polymer nanocomposite fibers are different from those of the dried as-received nanoparticles.