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Cubic phase magnetite (Fe3O4) nanoparticles have been synthesized with simple and effective co-precipitation methods using citric acid as a surfactant. The structure and particle size distribution of synthesized Fe3O4nanoparticles were examined with the help of a Fourier transform infrared (FTIR) spectrometer, ultraviolet–visible (UV–Vis) absorption spectrometer, X-ray diffractometer (XRD), and scanning electron microscope (SEM). The electrochemical behaviors of the Fe3O4nanoparticle electrode were analyzed using cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) in an acidic medium. The Fe3O4electrode revealed a noticeable pseudocapacitive performance with a large specific capacitance of 126 Fg−1at a discharge current of 2.5 Ag−1. In addition, it showed a specific power of 311.9 Wkg−1and specific energy of 18.88 Wh kg−1. The cycle life test results after 5000 cycles explained that it could retain 52.6% of the initial capacitance.

This study reports on the effect of the addition of Glycine to Hank's solution on the in-vitro corrosion behavior of AZ31 magnesium (Mg) alloy at 37 ℃ and a pH of 7.4 studied by using potentiodynamic polarization (PDP), hydrogen collecting techniques and electrochemical impedance spectroscopy (EIS) in combination with surface characterization techniques such as optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy analysis (XPS). The results reveal that adsorption of glycine initially subdues the dissolution of AZ31 Mg alloy while in long run it enhances the dissolution of the alloy due to the commencement of the chelation effect of glycine with Ca2+ released from hydroxyapatite. The chelation of glycine with Ca2+ induces the formation of cracks in the surface film which further promotes the dissolution of AZ31 Mg alloy thereby forming a porous corrosion products layer on the surface of the alloy. As a result, both the continuous dissolution of AZ31 magnesium alloy and the hydrogen evolution rate (HER) are enhanced with increasing the immersion time in Hank's solution. [ABSTRACT FROM AUTHOR]

• The attached bentonite layer could restrain the cathodic oxygen reduction by virtue of its barrier effect on blocking the diffusion of oxygen. • The barrier performance of bentonite could be deteriorated by iron corrosion products, which further accelerated the steel corrosion. • New equivalent circuits were proposed to describe the effects of bentonite content on the cathodic and anodic process of steel corrosion. • Effects of bentonite content on the corrosion mechanism of low carbon steel in the long-term immersion have been discussed. The effects of bentonite content on the corrosion behavior of low carbon steel in 5 mM NaHCO 3 + 1 mM NaCl + 1 mM Na 2 SO 4 solution were investigated by electrochemical measurements combined with X-ray diffraction (XRD) and scanning electron microscopy (SEM). In the initial immersion stage, the cathodic process of low carbon steel corrosion was dominated by the reduction of dissolved oxygen, while it transformed to the reduction of ferric corrosion products with the immersion time. The presence of bentonite colloids could suppress the cathodic reduction of oxygen due to their barrier effect on the diffusion of oxygen. However, the barrier performance of bentonite layer was gradually deteriorated due to the coagulation and separation of bentonite colloids caused by the charge neutralization of iron corrosion products dissolved from the steel substrate. More bentonite colloids could maintain the barrier effect for a long time before it was deteriorated by the accumulation of corrosion products. Conversely, it could lose the performance completely, and the corrosion behavior of low carbon steel reverted to the same as that in the blank solution. [ABSTRACT FROM AUTHOR]

Electromagnetic interference (EMI) pollution has now become a subject of great concern with the rapid development of delicate electronic equipment in commercial, civil, and military operations. There has been a surge in pursuit of light-weight, adaptable, effective, and efficient EMI screening materials in recent years. The present article addresses a simple and sensitive approach to synthesize a core/shell carbon nanotube/MoS2heterostructure supported on reduced graphene oxide (CNT/MoS2-rGO nanohybrid) as an efficient electromagnetic shielding material. The structural and morphological characteristics were accessed through X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy, augmenting successful formation of the CNT/MoS2-rGO nanohybrid. The shielding performance of the as-synthesized samples has been accessed in a wide frequency range of 8–12 GHz. A CNT/MoS2-rGO nanohybrid demonstrates a better EMI shielding performance in comparison to MoS2nanosheets and MoS2-rGO nanohybrid individually. The CNT/MoS2-rGO nanohybrid having a thickness ∼1 mm shows excellent total shielding effectiveness (SET) as high as 40 dB, whereas MoS2and MoS2-rGO hybrid lags far, with the average value of SETas 7 and 28 dB, respectively. It also demonstrates that the nanohybrid CNT/MoS2-rGO shields the EM radiation by means of absorption through several functional defects and multiple interfaces present in the heterostructure. Herein, we envision that our results provide a simple and innovative approach to synthesize the light-weight CNT/MoS2-rGO nanohybrid having flexibility and high shielding efficiency and widen its practical applications in stealth technology.

The dissolution behavior of platinum alloy has been investigated for application in polymer electrolyte membrane fuel cell catalyst. Pt alloys (Pt-Co, Pt-Ni, Pt-Fe) were prepared by arc melting. The electrochemical behavior was studied by cyclic voltammetry (CV) in 0.5M H2SO4 at 298 K. The test solutions were analyzed by using ICP to determine the amount of dissolved ions. The results of CV of Pt-Co, Pt-Ni and Pt-Fe alloy electrodes indicated that the current density of Pt-Co, Pt-Ni was much smaller than that of Pt-Fe alloy and close to that of Pt electrode. The ICP results revealed that amount of dissolution for Pt-Co and Pt-Ni alloys were much lower than that for Pt-Fe alloy.

30 keV low-energy ion-implantor was used to synthesize silicon oxynitride (SixOyNz) insulating layers. The reactive ion-beams of molecular oxygen (16O2+) and nitrogen (14N2+) were co-implanted sequentially into silicon at room temperature in the ratio 1:1 to total fluence level ranging from 5x1016 to 1x1018 ions-cm-2. Characterization of ion-beam synthesized SixOyNz layers was carried out by X-ray diffraction (XRD) and current-voltage (I-V) measurements before and after rapid thermal annealing (RTA) treatments at different temperatures. XRD studies of the as implanted samples indicate formation of oxynitride layers with the presence of implanted oxygen mostly in the oxide phase and nitrogen in the dissolved form in the implanted silicon layer. RTA of the samples at higher temperature results in the transformation of oxide and nitride into new phases. Al-ion-beam synthesized oxynitride-Si (MIS) devices were fabricated with as implanted and annealed samples to study current density voltage (J-V) characteristics. These results show ohmic conduction at low voltages and non-ohmic behavior at higher fields. Results obtained in the present work show higher electrical resitivity and the lower trap density for the ion-beam synthesized oxynitride films than those films prepared by other methods.