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Metronidazole (MNZ) is non-biodegradable and highly soluble in water, it is easy to accumulate in the aquatic environment, which has toxic effects in clinical applications such as causing peripheral neuritis, cardiogenic shock and pseudomembranous colitis. In this paper, Co/NC@w-NiSO 4 ·NiS 2 nanospheres were successfully constructed by coating w-NiSO 4 ·NiS 2 on the surface of ZIF-67 as the growth substrate via hydrothermal method and subsequent calcination for electrochemical detection of metronidazole (MNZ). The nanostructure and composition of the materials were confirmed by SEM, TEM, FT-IR and XPS. The sensitivity of Co/NC@w-NiSO 4 ·NiS 2 sensor for MNZ detection is 1977.14 μA/(mM·cm2); the limit of detection (LOD) is as low as 0.009 μM and the linear range is 1 ∼ 200 and 200 ∼ 1000 μM. Moreover, the modified sensor can resist the interference from many traditional living substances, and has good reproducibility and stability. High catalytic activity requires effective molecular transport and exposure of active sites. The successful construction of Co/NC@w-NiSO 4 ·NiS 2 nanostructure promotes the dispersion of materials and the migration of reactants on the electrode surface, and the w-NiSO 4 ·NiS 2 coating on the irregular particles of ZIF-67-derived cobalt/nitrogen-doped carbon suppressed the stacking of the w-NiSO 4 ·NiS 2 nanosheets to expose more catalytic sites. These factors are conducive to increasing the catalytic activity of the modified sensor for highly sensitive MNZ detection and ensuring the activity of catalyst in multiple catalytic cycles. [Display omitted] • Co/NC@w-NiSO 4 ·NiS 2 composite was synthesized via hydrothermal method and pyrolysis. • The composite suppressed the stacking of nanosheets to expose more catalytic sites. • The sensitivity of electrochemical sensor is 1977.14 μA/(mM·cm2). • The electrochemical sensor was used for MNZ analysis in human blood plasma samples. [ABSTRACT FROM AUTHOR]

To achieve superamphiphobic properties on the surface of copper, a novel strategy for fabricating multi-level micro-nano superamphiphobic membranes by laser-electrochemistry subtractive-additive manufacturing method is explored. To test the properties of the metal surface prepared by this method, a variety of testing experiments are carried out. The experiment results shows that the contact angle (CA) of water and oil droplets are 161° ± 4° and 151° ± 4°, while those rolling CAs are 2° and 10°, which shows that the prepared surface had excellent superamphiphobic properties. Through the wettability test at different temperatures, the surface hydrophobicity of the prepared samples at low temperature 5 °C is worse than that at a room temperature 25 °C. According to droplet bounce test, the water drops experiences two complete bouncing processes on the surface of the prepared samples when the laser scanning interval is equal to the laser spot diameter, which indicates that the stable Cassie state is related to the multi-level micro-nano structures. In addition, the superamphiphobic surfaces fabricated in this paper have perfect functionality and stability, which provides a novel method for the potential application in the automotive, aerospace, and shipbuilding industries. [Display omitted] [ABSTRACT FROM AUTHOR]

Cobalt (Co) is the interconnect metal of integrated circuits with the feature size of 10 nm and below, and Co corrosion is the main problem in cobalt interconnect chemical mechanical polishing (CMP). The introduction of inhibitors is one of the most ideal approaches to reduce corrosion. In this work, useful insights into the corrosion inhibition performance of nicotinic acid (NA), a green inhibitor, on cobalt film in alkaline medium were investigated via electrochemical characterization, surface analysis, quantum chemical calculation, and molecular dynamics (MD) simulation, as well as the adsorption mechanism at atomic level was explored. NA belongs to anodic erosion inhibitor and its inhibition efficiency reached a maximum of 86.65 % at the concentration of 80 mM pH 10, which was identified by the contact angle and potentiodynamic polarization (PDP) test. The electrochemical impedance spectra (EIS) suggested that the surface resistance was enhanced to prevent corrosion. Free energy obtained from the Langmuir model indicates that NA molecules are physically and spontaneously adsorbed on cobalt surface. XPS results further confirmed this point, which reveals that NA exists in the form of Nic2− in alkaline solution and forms a Co(OH) 2 (Nic2-) molecule group (Co(II)-NA) on Co surface. Additionally, quantum chemical calculations based on density function theory (DFT) have approved that C N bond and carboxyl group are the active sites of NA molecule and form the most significant electrostatic adsorption force with cobalt atoms. Moreover, it can be inferred from MD simulations that NA molecules are spontaneously and physically adsorbed on the cobalt surface at a certain angle. In a word, NA manifests its effectiveness in corrosion inhibition of cobalt and will become a potential cobalt CMP inhibitor. The research methods and results of this paper are beneficial to the study of the adsorption characteristics and inhibition mechanism of inhibitors on the metal surface, and provide a theoretical basis for optimizing the composition of Co CMP slurry. The major mechanism of corrosion inhibition effect by nicotinic acid (NA) is to form a passivation film which adsorbs on cobalt (Co) surface so as to strengthen the surface impedance and isolate the corrosion medium. In an alkaline environment (pH 10), NA exists in the form of Nic2− ions, which are negatively charged. Driven by electrostatic forces and Van der Waals forces between NA molecule (N atom and the carboxyl) and cobalt atom, Nic2− ions are appealed to the Co(OH) 2 , leading to the appearance of Co(II)-NA molecule groups. NA molecules produce a single or multilayer self-assembled Co(II)-NA film on the cobalt surface and further prevent the corrosion on Co film. [Display omitted] [ABSTRACT FROM AUTHOR]