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A sea-urchin-like CuO/ZnO porous nanostructure is obtained via a simple solution method followed by a calcination process. There are abundant pores among the resulting nanowires due to the thermal decomposition of copper—zinc hydroxide carbonate. The specific surface area of the as-prepared CuO/ZnO sample is determined as 31.3 m2·g−1. The gas-sensing performance of the sea-urchin-like CuO/ZnO sensor is studied by exposure to volatile organic compound (VOC) vapors. With contrast to a pure porous sea-urchin-like ZnO sensor, the sea-urchin-like CuO/ZnO sensor shows superior gas-sensing behavior for acetone, formaldehyde, methanol, toluene, isopropanol and ethanol. It exhibits a high response of 52.6–100 ppm acetone vapor, with short response/recovery time. This superior sensing behavior is mainly ascribed to the porous nanowire-assembled structure with abundant p—n heterojunctions.

Simonkolleite is a zinc-layered hydroxide salt with the formula Zn5(OH)8Cl2·H2O. It has a platelet morphology and can be used for many applications, owing to both its layered structure and its nature as a hydroxide salt. It can be prepared via a simple precipitation from ZnCl2 and NaOH in water thermostated at 50 °C. Depending on the synthesis conditions, we could obtain different sizes and a hybrid containing parts of ZnO. We studied the influence of the OH:Zn molar ratio, the addition order, and the maturation time after the reaction was completed. With the support of pH profiles, kinetic studies, and thermodynamic equilibrium data, we were able to propose a global synthesis mechanism explaining the influence of those three parameters and identify the range of conditions in which simonkolleite can be formed. Depending on the desired application, we were able to synthesize bigger or smaller layered crystals of simonkolleite, in the presence of absence of ZnO.

Recently emerged metallic zinc (Zn) is a new generation of promising candidates for bioresorbable medical implants thanks to its essential physiological relevance, mechanical strength, and more matched degradation pace to that of tissue healing. Zn‐based metals exhibit excellent biocompatibility in various animal models. However, direct culture of cells on Zn metals yields surprisingly low viability, indicating high cytotoxicity of Zn. This contradicting phenomenon should result from the different degradation mechanisms between in vitro and in vivo. To solve this puzzle, the roles of all major players, i.e., zinc phosphate (ZnP), zinc oxide (ZnO), zinc hydroxide (Zn(OH)2), pH, and Zn2+, which are involved in the degradation process are examined. Data shows that ZnP, not ZnO or Zn(OH)2, significantly enhances its biocompatibility. The mild pH change during degradation also has no significant impact on cell viability. Collectively, ZnP appears to be the key to controlling the biocompatibility of Zn implants and could be applied as a novel surface coating to improve biocompatibility of different implants. Spontaneously formed interfacial zinc phosphate (ZnP), instead of zinc oxide (ZnO) or zinc hydroxide (Zn(OH)2), is the key to controlling the biocompatibility of Zn‐based metals. The ZnO–Zn(OH)2 layer shows a high cytotoxicity while the dense and uniform ZnP interfacial layer enhances biocompatibility and promotes tissue integration.

The degradation of organic pollutants in wastewaters assisted by oxide semiconductor nanostructures has been the focus of many research groups over the last decades, along with the synthesis of these nanomaterials by simple, eco-friendly, fast, and cost-effective processes. In this work, porous zinc oxide (ZnO) nanostructures were successfully synthesized via a microwave hydrothermal process. A layered zinc hydroxide carbonate (LZHC) precursor was obtained after 15 min of synthesis and submitted to different calcination temperatures to convert it into porous ZnO nanostructures. The influence of the calcination temperature (300, 500, and 700 °C) on the morphological, structural, and optical properties of the ZnO nanostructureswas investigated. All ZnO samples were tested as photocatalysts in the degradation of rhodamine B (RhB) under UV irradiation and natural sunlight. All samples showed enhanced photocatalytic activity under both light sources, with RhB being practically degraded within 60 min in both situations. The porous ZnO obtained at 700 °C showed the greatest photocatalytic activity due to its high crystallinity, with a degradation rate of 0.091 and 0.084 min−1 for UV light and sunlight, respectively. These results are a very important step towards the use of oxide semiconductors in the degradation of water pollutants mediated by natural sunlight.

The unstable zinc anode/electrolyte interface induced by corrosion, interfacial water splitting reaction, and dendrite growth seriously degrades the performances of metal Zn anode in aqueous electrolyte. Herein, the nucleation and growth of zinc hydroxide sulfate (ZHS), an interfacial by-product, has been tailored by Tween 80 in the electrolyte, which thereby assists in in-situ forming a dense solid electrolyte interphase (SEI) with small-sized ZHS and evenly distributed Tween 80. This SEI has high corrosion resistance and uniform distribution of zinc ions, which not only contributes to blocking the interfacial side reactions but also induces stable and calm zinc plating/stripping. Consequently, the modified electrolyte can confer the assembled Zn∥Zn symmetric cell with a stable operation life over 1500 h at 1 mA·cm −2 and 1 mAh·cm −2 as well as the practical Zn∥NH 4 V 4 O 10 full battery with a high-rate capacity of 120 mAh·g −1 at the current density of 5 A·g −1 . This work provides a way for regulating and reusing interfacial by-products, and a new sight on stabilization electrodes/electrolyte interfaces.

Zinc hydroxide has been reported as an effective precipitating reagent for removing proteins in biological samples. This procedure is quite effective for removing interfering proteins before the chromatographic separation of small organic compounds. However, preliminary data suggested that also some small molecules could precipitate together with proteins and zinc hydroxide. Therefore, herein it is reported a study on a panel of drugs having different chemical structures. The results suggest that the common trait of organic molecules coprecipitating with zinc hydroxide is to have acidic groups, while neutral or basic molecules are not affected by zinc hydroxide precipitation. Such observations were consistent with some analyses conducted on hydroalcoholic extracts prepared from natural edible materials such as green tea. In such matrices, a quantitative coprecipitation of polyphenols was obtained upon inducing the precipitation of zinc hydroxide, while alkaloids such as caffeine remained selectively isolated in the supernatants. Interestingly, the compounds coprecipitated with zinc hydroxide can be easily and quantitatively recovered as well, just by redissolving the precipitate. These findings open potential applications for the isolation of specific classes of compounds from crude natural extracts and for the use of zinc hydroxide to remove interfering compounds before chromatographic analyses.

Background Considering the efficacy of antimicrobial photodynamic therapy (PDT) in inactivating bacteria, this study reports that zinc hydroxide chloride nanosheets (ZHC-NSs) are useful for this purpose. Materials & methods The characterization of ZHC-NSs was performed using microscopic and spectroscopic techniques. The irritation test, acute toxicity test, and genotoxicity test of ZHC-NSs were evaluated and their effects on human pulp fibroblast cells (HPFC) viability, intracellular reactive oxygen species (ROS) levels, and antibacterial activity of ZHC-NSs (1–8 mg ml −1 ) alone or in light conditions were investigated. Results The ZHC-NSs structure showed a crystalline form and their sheets’ thickness had an average size of 129.6 ± 19.50 nm. ZHC-NSs did not severely damage internal organs and were not genotoxic. The cytotoxic effect of ZHC-NSs on HPFC was concentration-dependent so that ZHC-NSs at higher concentrations (4 and 8 mg ml −1 ) killed half of the HPFC cells. When ZHC-NSs were used in combination with a 980 nm diode laser, namely ZHC-NS © , ROS production increased and led to enhanced antibacterial activity against Streptococcus   mutans in planktonic and biofilm form. A statistically significant difference was found between ZHC-NSs without laser irradiation and photoexcited ZHC-NSs. Conclusion ZHC-NSs © with the potential ability to produce ROS could be effective in complementary treatment against S. mutans .

Herein, a simple electrochemical process was proposed for the electrochemical modification of a graphite rod electrode (GrE) with a zinc hydroxide thin film. Two sequential steps were enough for the modification of the graphite rod using chronoamperometry technique. In the first step, the metallic zinc film was electrochemically deposited on GrE surface at pH 4.5, by reducing Zn 2+ on GrE at − 1.78 V vs. saturated calomel electrode (SCE) for only 210 s forming GrE@ZnNPs. In the second step, the electrode previously coated with a metallic zinc film was oxidized in buffer solution at pH 7, at 0.1 V vs. SCE for 360 s to form GrE@Zn(OH) 2 NPs. X-ray diffraction, optical microscope and interferometric microscope were used to confirm and identify the obtaining of the desired layer (Zn and Zn(OH) 2 nanoparticles (NPs) thin layer). Then, several electrochemical techniques were used before and after the modification in order to study the electrochemical properties of the bare and modified electrodes. These analyses are based on the comparison of open-circuit potentials, polarization resistances of fast electrochemical systems ( R p ), potentiodynamic polarizations (Tafel curves) and electrochemical impedances.

The crystalline zinc borate phase ZnB3O4(OH)3, known in commerce as 2ZnO·3B2O3·3.5H2O, is an important industrial material used as a fire-retardant synergist in polymers, a source of micronutrients in agriculture, and a preservative in building materials. It lends durability to wood composite building materials by inhibiting attack by wood destroying organisms. The hydrolysis chemistry of this zinc borate is relevant to its industrial use. ZnB3O4(OH)3 exhibits incongruent solubility, reversibly hydrolyzing at neutral pH to insoluble Zn(OH)2 and soluble B(OH)3. It is sparingly soluble with a room temperature solubility of 0.270 wt% in terms of its equivalent oxide components in solution, comprising 0.0267 wt% B2O3 and 0.003 wt% ZnO. Aspects of the hydrolysis chemistry of zinc borate under neutral pH conditions are discussed.

The advantage of the concurrent development in polymers flame retardant is illustrated by the hybrid material technology of flame retardants, which, as opposed to conventional flame retardants, blends distinct elements into a whole. Layered zinc hydroxide, sodium dodecyl sulfate, borate ion, and polydimethylsiloxane were used to make a flame retardant composite, a new organic–inorganic hybrid material as a flame retardant. Using analysis methods, the structures of materials were investigated following synthesis. The interlayer space of the layered zinc hydroxide was studied for the intercalation of ions, according to the X-ray diffraction studies. The chemical structure of produced compounds was assessed with energy dispersive spectrum and fourier transforms infrared spectroscopy. The morphology of the synthesized materials was identified using emission scanning electron microscopy. The thermal resistance of the synthesized samples and coating samples was measured by thermogravimetric analysis. By adding a little amount of flame retardant composite flame retardant, the fire danger of epoxy resin was significantly decreased. According to the plate temperature and flammability test experiment, flame retardant composite with 0.075% w/w led to showed that the synergistic role of the flame retardant composite compound including zinc, borate ions, and also the polydimethylsiloxane played a significant role in reducing the risks of epoxy resin hazard flaming as well as reducing heat and damage to the metal substrate. Graphical Abstract