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Photocatalytic degradation is becoming an increasingly attractive method for addressing environmental remediation challenges. In this work, the novel pure PWO/ZnO and doped PWO: Er/ZnO: Ag heterostructure nanocomposites with premier photocatalytic efficiency were synthesized via a simple co-precipitation method followed by a solvothermal procedure. X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX), and ultraviolet-visible (UV-Vis) absorbance measurements techniques were employed to characterize the structural and optical properties. HRTEM images prove the possibility of intimate contact formation at the pure and doped PWO/ZnO heterostructure nanocomposite interfaces. The photocatalytic performance of the PWO/ZnO heterostructure nanocomposites in the degradation of the methylene blue (MB) and methyl orange (MO) dyes under UVA light was evaluated. The photocatalysts' ability in the mineralization of organic pollutants was confirmed by the TOC test. BET and zeta potential analyses were used to study the dye adsorption mechanisms. Additionally, adsorption isotherms and kinetics have been investigated to describe the adsorption of MB and MO into the samples. The degradation rates of MB with PWO/ZnO and PWO: Er/ZnO: Ag heterostructure nanocomposites were 4.7 and 6.6 times higher than those of PWO and PWO: Er nanoparticles. This rate for MO degradation is 5.2 and 3.5 times higher than that of pure PWO and PWO: Er nanoparticles, respectively. This study outlines an easy method to develop innovative, highly effective heterostructure nanocomposites capable of converting UVA light into photocatalytic performance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Offshore pipelines are vulnerable against erosion/wear deterioration mechanisms that can be controlled through the use of proper surface coatings, such as polymer matrix nano-composite (PMNC) coatings that are well-known for their ease of production, availability and applicability. Epoxy, as a versatile rigid and brittle resin and polyurethane with proper chemical/mechanical properties, are potential candidates to make the matrix of these composites. A combination of these polymers can also enhance the mechanical behaviors, glass transition temperature and flexibility. In addition, the desired coating characteristics, such as adhesion to metal substrate, mechanical properties, erosion/wear resistivity and UV absorbance, can be further improved through the addition of appropriate nanoparticles within the polymer matrix. Especially, nanoparticles can improve the erosion/wear resistance of polymers because of establishing high strength bonds between the polymer chains and the reinforcements besides enhancing other required properties. The present work is a review on PMNC coatings that contain epoxy, polyurethane or EP/polyurethane as a polymer matrix along with the details of the nanoparticle reinforcements, such as alumina, silica, titanium oxide, zinc oxide, clay and carbon-based materials. The effect of these nanoparticles on the properties of composite coatings has also been investigated. [ABSTRACT FROM AUTHOR]

Objective(s): The use of cationic surface-active agents (surfactant) in the synthesis of nanoparticles, with formation of micelle, can act as a template for the formation of meso-porous silica. Changes in the concentration of surfactants can affect the structures and properties of the resulting nanoparticles. Materials and Methods: Magnetite nanoparticles were prepared as cores using the coprecipitation method. Silica shells were formed on the prepared cores using sol-gel through the single-step process. During synthesis, cetrimonium bromide (CTAB) was used as a surfactant at low (0.1 g), medium (1 g), and high concentrations (7 g), and the effects on the properties of the nanoparticles were investigated. The coreshell nanoparticles were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). In addition, the surface porosities of the nanoparticles were evaluated using the BET and BJH methods. The vibrating sample magnetometer (VSM) was also employed to assess the magnetic characteristics of the synthesized samples. Results: The results of XRD indicated that the nanoparticles were composed of magnetite and silica, while the SEM and TEM images confirmed the presence of uniform spherical particles with a core-shell structure. According to the results of the VSM tests, all nanoparticles showed super-paramagnetic behaviors. Moreover, the increased concentration of CTAB led to an increment in saturation magnetization (Ms), size, and volume of the surface pores, while the specific surface area of the nanoparticles decreased. Conclusion: According to the results, the properties of the silica shell could be adjusted in terms of pore characteristics and magnetic behavior by changing the concentration of the surfactant. [ABSTRACT FROM AUTHOR]

[Display omitted] • Developing a graphite nanocrystals (GNCs)/paper electrode using ion beam sputtering deposition method. • An electrochemical genosensor using the cDNA-functionalized Au@CD core/shell NPs for the SARS-CoV-2 RdRP detection. • Engineering a signal-on mechanism based on the intercalation of toluidine blue into the large grooves of cDNA-RdRP duplex. Currently, the development of biosensors is an urgent need due to the rapid spread of SARS-CoV-2 and the limitations of current standard methods for the diagnosis of COVID-19. Hence, many researchers have focused on the design of high-performance biosensors for measuring coronavirus genes. In this study, a voltammetric genosensor was developed for the determination of SARS-CoV-2 RdRP gene based on the format of cDNA probe/Au@CD core–shell NPs/graphite nanocrystals (GNCs)/paper electrode. For the first time, graphite nanocrystals were used in the electrochemical biosensor design. This genosensor was exposed to different concentrations of virus gene and then the hybridization between cDNA probe and RdRP gene was monitored by redox-active toluidine blue (TB). With increasing the RdRP concentration, the reduction peak current of TB enhanced in a linear range of 0.50 pM-12.00 nM according to the regression equation of I (μA) = 7.60 log C RdRP (pM) + 25.78. The repeatability with a RSD of 2.2% clearly exhibited that the response of modified electrode is stable because of the high adhesion of GNC layer on the paper substrate and the high stability of cDNA-Au@CD bioconjugates. The spike-and-recovery studies showed the acceptable recoveries for the sputum samples (>95%). [ABSTRACT FROM AUTHOR]

Hancing the corrosion resistance of various composites is a challenge; however, the mechanical characteristics of composites are usually high without any risks. Thus, in this paper, Al 2 O 3 nanoparticles with various percentages as reinforcements were added to the brass matrix to increase the corrosion resistance. Tafel polarization, electrochemical impedance spectroscopy (EIS), and weight loss measurements were performed to investigate the corrosion characteristics of manufactured nanocomposites. Moreover, field emission scanning electron microscopy (FESEM) was used to study the surface morphology of nanocomposites before and after exposure of specimens to 0.6 M NaCl solution. FESEM images and the related energy dispersive spectroscopy results showed that Al 2 O 3 nanoparticles were distributed in the α-phase of the matrix homogeneously. Corrosion rates of nanocomposite decreased significantly by about 41–99% compared to the matrix without reinforcement. Weight loss measurements showed that the weight loss of nanocomposites at 95 °C was lower than that at 25 °C. This was attributed to the formation of copper/zinc chloride salts on corroded surfaces. • New corrosion-resistant leaded-brass matrix nanocomposite made by casting. • The optimum percentage of Al 2 O 3 nanoparticles in the matrix was 1.5 wt%. • The utilized nanoparticle reduced the corrosion rates by about 100%. • Al 2 O 3 nanoparticles were distributed homogeneously in the matrix. [ABSTRACT FROM AUTHOR]

Mixed phases nanozirconia was synthesized using the sol-gel process in different basic pH. Calcination was performed at 700 °C for 1 and 2 h. The synthesis process and characterization of the nanoparticles were studied by TGA, DTA, FTIR, XRD, FE-SEM and UV–visible. The presence of stable monoclinic and meta-stable tetragonal phases was confirmed by X-ray diffraction patterns for synthesized powders. As pH increased, the amount of tetragonal phase and crystallite size is increased and decreased, respectively. Also, due to the increase of calcination time, the amount of tetragonal phase and crystallite size increased. Micrographs confirmed that the particle shape is semi-spherical after calcination. Moreover, the size of zirconia nanoparticles decreased to 29.8 and 32.9%, as pH increased from 8 to 10 for samples with 1 and 2 h calcination time, respectively. The lowest particle size, 19.3 nm, is related to the sample that was synthesized at pH 10 and calcined at 700 °C for 1 h. UV analysis showed that by increasing the amount of pH, the amount of absorption and the band gap decreased and increased, respectively. [ABSTRACT FROM AUTHOR]