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This study investigated the failure behavior and mechanism of conductive and corrosion-resistant film on magnesium alloy under "double 85" test conditions. The surface morphology, microstructure, and composition of ITO composite conversion film (ITO film) at different damp-heat test times were analyzed using X-ray photoelectron spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy, and the corrosion resistance was investigated using an electrochemical workstation in contact with a 3.5 wt.% NaCl solution. The electrical contact resistance (ECR) was measured using the four-wire Kelvin detection technique, and the bandgap was determined using an ultraviolet diffuse reflectance spectrometer. The results demonstrated that the ECR of the ITO film increased from 10−1 Ω in−2 to 106 Ω in−2, and the bandgap increased from 2.363 to 2.777 eV after the damp-heat test. In addition, the impedance arc radius of the film decreased to approximately one-fifth of its original value, and the impedance modulus value decreased to less than 104. These findings indicated that exposure to a damp-heat environment resulted in an increase in the electrochemically active points within the film participating in the electrochemical reactions and expansion of the electrochemical reaction area. This exacerbated the corrosion of the magnesium substrate because it resulted in the destruction of the film, leading to an increase in the number of pores and defects, which heightened the exposure of the substrate to corrosive media. Furthermore, Cl− ions could easily penetrate through cracks in the film, which promoted charge transfer processes and accelerated the electrochemical corrosion reactions. In summary, these factors collectively resulted in the failure of the film's conductivity and corrosion resistance. [ABSTRACT FROM AUTHOR]

We report on the synthesis of SnO2 nanoparticles and SnO2:CNT hybrids, via a one-step solgel method. Herein, we investigate the influence of the synthesis conditions on their physical, chemical, optical and electrochemical properties. The crystalline structure, nanoparticle size and morphology are assessed by X-ray diffraction and transmission electron microscopy. The chemical states are elucidated by X-ray photoelectron and Raman spectroscopies. Their electrochemical behavior is studied by cyclic voltammetry. Overall, an oxygen-poor environment during the synthesis leads to smaller SnO2 nanoparticles, along with an increased number of surface defects. Photoluminescence spectroscopy demonstrates that under an oxygen-poor environment, bridging-oxygen vacancies are more abundant. Additionally, SnO2 nanoparticles containing a higher amount of oxygen vacancies exhibit a higher cycling stability of 90%. The cycling stability is further enhanced in hybrid SnO2:CNT. The electrochemical behavior is corroborated to the surface defects and in turn, the band bending mechanism in SnO2 n-type semiconductor. [ABSTRACT FROM AUTHOR]

This work explores the thickness effect of RF magnetron-sputtered nickel oxide (NiO) thin films for evaluating their H2S gas-sensing characteristics. NiO thin films were prepared on alumina substrates by varying the deposition time, and the resulting film thicknesses were 25 nm, 52 nm, and 76 nm. X-ray diffraction results demonstrate the polycrystalline nature and cubic structure of NiO thin films. Photoluminescence spectroscopy measurements revealed increased defect content (Ni interstitials and O vacancies) in the 52-nm-thick NiO thin film. Furthermore, X-ray photoelectron spectroscopy results confirmed the thickness effect on NiO thin film stoichiometry. Conductivity measurements at working temperatures ranging from 200 to 450 °C were also used to investigate the gas-sensing tests. The NiO thin film with a thickness of 52 nm proved to be an excellent H2S gas sensor, with a remarkable sensor response of 260% and a response/recovery time of ~ 52 s/23 s for 50 ppm H2S at a relatively low operating temperature of 275 °C. Additionally, the film displays a low H2S detection limit of ~ 0.2 ppm. This study investigates the relationship between the thickness, structural, optical, and electrical properties of NiO thin film-based H2S gas sensors and their gas-sensing capabilities. [ABSTRACT FROM AUTHOR]

As the global environmental problems of energy shortage and pollution are becoming prominent, the trend of using natural fibers as the reinforcement in the composite is increasing. In this study, the hemp fiber mat-reinforced polylactic acid (PLA) composite was designed and fabricated. As the fiber and matrix have different water affinity, the plasma treatment was used to improve the interfacial properties between them. After plasma treatment, scanning electron microscope (SEM), water contact angle and X-ray photoelectron spectroscopy (XPS) detection were conducted, and the results showed the effectiveness of plasma treatment. To further improve the interfacial properties and impart the electromagnetic shielding to the composites, the graphite and carbon black were respectively added into the interface by the spraying method. The results showed that the composite in which the fiber mat was plasma treated and 10wt% graphite added had the highest bending strength, and the after-fracture morphology of this composite showed good damage resistance. The reason lies in the synergistic effect from the combination of graphite and plasma treatment. Additionally, the electromagnetic shielding effectiveness of the above composite had the highest value of 20.25 dB in X-band frequency range. [ABSTRACT FROM AUTHOR]

The present work describes the effect of long-term (8 weeks) high-temperature oxidation (500 °C) on the formation of an oxide layer as well as on the microstructure and mechanical properties of the 3D-printed 18Ni-300 maraging steel. For this purpose, samples produced by additive manufacturing in the as-built and the as-built + solution annealed and aging treated states were used. The as-built + solution annealed and aging treated material was found to be more prone to oxide layer formation due to a homogeneously distributed Ni3Mo intermetallic phase in the material matrix compared to the as-built material. The 8 weeks long exposure to a temperature of 500 °C has caused the formation of a thick oxide layer that exhibited a very bad adhesion with the metal matrix/oxide. The X-ray diffraction analysis confirmed the formation of a layer with a complex phase composition: martensite, austenite, Fe2O3, and Fe3O4. Moreover, the presence of CoFe2O4 was determined on the thin outer oxide layer using X-ray photoelectron spectroscopy. The phenomenon of over-aging was found to be the most significant after the first week of high-temperature oxidation. Then, a negligible change in the microhardness was observed throughout the entire experiment. X-ray diffraction analysis and energy dispersive spectroscopy confirmed the phase composition of the alloy corresponding to 75% of martensite + 25% of austenite as well as the change of Ni3Mo precipitate to Ni3(Mo, Ti) type after the long-term oxidation. [ABSTRACT FROM AUTHOR]

Graphene is a two-dimensional carbon material with unique properties, such as high thermal and electrical conductivity, mechanical strength, elasticity, and biocompatibility. The methods used to synthesize graphene affect its structural properties, including flaws, layer count, crystalline domain size, and impurities, ultimately affecting the properties and performance of graphene-based materials. This review aims to analyze the methods used to characterize graphene, using both ISO/IEC standards and current literature as references. The discussed techniques are diverse, yet complementary, and include ultraviolet–visible spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray absorption near edge structure, atomic force microscopy, scanning electron microscopy, transmission electron microscopy, the Brunauer–Emmett–Teller method, thermogravimetric analysis, in-line four-point probe, resonant cavity and terahertz time-domain spectroscopy, besides an alternative method to determine the graphene domain. By employing rigorous characterization techniques, researchers and industry professionals can ensure the reliability, effectiveness, and trustworthiness of graphene-based materials for various applications. [ABSTRACT FROM AUTHOR]

The self-supported Co–Fe LDH@Ni(OH)2 material is successfully prepared on a foam nickel substrate through two hydrothermal processes. The phase structure and microstructure of the electrode material are investigated through X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and transmission electron microscope (TEM) analyses. The electrode materials undergo electrochemical and electrocatalytic tests using an electrochemical workstation. This study demonstrates that the specific capacitance of the Co–Fe LDH@Ni(OH)2 is 2626 mF cm−2 at 1 mA cm−2. Supercapacitors made of LDH@Ni(OH)2 electrode material operate exceptionally well. Both the power density and the energy density are 0.755 mW cm−2 and 32.5 μWh cm−2, respectively. As a catalyst material for electrochemical splitting of water, CoFe-LDH@Ni(OH)2 exhibits distinguished electrocatalytic properties. The overpotential is 242 mV at 50 mA cm−2 in HER, while that is 149 mV at 20 mA cm−2 in OER. Meanwhile, the CoFe-LDH@Ni(OH)2 electrocatalytic material also performs extremely well in the overall water electrolysis testing. The voltage is 1.65 V at 25 mA cm−2, which shows strong cyclic stability. The material provides a reliable guarantee for sustained and stable operation in various application scenarios. [ABSTRACT FROM AUTHOR]

This article conducted a study on ancient bronze coins unearthed in Huxian, Shaanxi, China. It was found that the coins corroded along the eutectoid phase, and there was an obvious corrosion layering phenomenon. From the outside to the inside, they were the outer rust layer, the transition layer and the matrix layer. When analyzing the chemical composition and corrosion products in different regions, various techniques such as metallographic microscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) and electron probe microanalysis (EPMA) were employed. It was determined that the outer rust layer primarily consisted of Cu2(OH)3Cl, while the transition layer was composed of an α phase and a corroded eutectoid phase (with the corrosion product being SnO2). In addition, combined with electrochemical tests, it was found that the rust layer has better protective performance on the substrate. Based on the above results, it is speculated that some ancient bronze cultural relics may have gone through two stages: the first stage is the market transaction stage after the coin casting is completed, and the second stage is the burial soil corrosion stage when the coins circulating in the market become funerary objects. Relevant research provides a certain theoretical basis for the protection of bronze cultural relics. [ABSTRACT FROM AUTHOR]

As a typical toxic substance in environmental water, phenolic pollutants, represented by p-nitrophenol, pose a great threat to the ecological environment. In this study, using WCl6 and oxalic acid as raw materials, a novel p-nitrophenol (PNP) sensor fabricated by tungsten phosphide (WP) nano-particles, has been successfully designed and constructed, which expanded the application of WP nano-materials in the field of electroanalysis. The successful synthesis of WP has been confirmed by a series of characterization techniques such as X-ray diffraction, scanning electron microscope, transmission electron microscope, and X-ray photoelectron spectroscopy. The electrochemical experiments were all carried out in phosphate buffer solution with the pH of 6.5. The WP nano-particles can electrocatalytically oxidize PNP to produce a current for the detection of PNP. The reaction sites of PNP are predicted by Gaussian 09 and Multiwfn. Prominent performance has been recorded for PNP sensor, attaining a wide linear range from 10.00 to 6500.00 μM, a low detection limit of 1.59 μM with the reliable selectivity, repeatability, and stability. Gratifyingly, the prepared sensor could satisfy the requirements of PNP determination in actual environmental water, such as tap water and rainwater. [ABSTRACT FROM AUTHOR]

Recently, nanozyme has found wide applications in various fields such as colorimetric sensors, biomedicine, and the environment. However, the development of highly active and multifunctional nanozyme remains a challenge. Herein, rod-shaped Co3O4/CeO2 heterostructure nanozyme was fabricated through a two-step method comprising a hydrothermal and mechanical grinding process. This method enables efficient creating of well-defined nanocomposite interfaces, resulting abundant oxygen vacancies in the Co3O4/CeO2 heterostructure, as evidenced by high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy characterizations. Benefiting from the above characteristics, Co3O4/CeO2 heterostructure exhibits peroxidase-mimicking activity and excellent catalytic performance. Therefore, a colorimetric sensor was constructed for the fast and sensitive quantitative analysis of tannic acid with good linearity in the range of 0.05–3.0 μM and a low detection limit of 29.8 nM. Furthermore, Co3O4/CeO2 nanozyme also shows remarkable efficiency in degrading the pollutant rhodamine B, achieving nearly complete degradation within 20 min. The findings spotlight the potential of highly active nanozymes for environmental sensing and remediation applications, emphasizing the importance of interface engineering in heterogeneous nanostructures to enhance their catalytic performance. [ABSTRACT FROM AUTHOR]

Central nervous diseases caused by noradrenaline (NA) have attained special attention. NA is involved in many different physiological functions that occur throughout the central nervous system, including modifying sensory input, attention regulation, arousal, and sleep regulation. Hence, rapid, precise, and trustworthy NA detection is crucial. Here we have created Nd(VO4)/GA nanocomposite for the sensitive and selective detection of noradrenaline. Successful fabrication of Nd(VO4)/GA nanocomposite was verified by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) techniques. Optical properties were evaluated by colorimetric and fluorometric detection using UV–Vis absorption and photoluminescence spectroscopy. The created sensor has demonstrated superior noradrenaline detection capabilities using fluorometry with an LOD of 48.48 nM in a wide linear range of 6–215 nM, and for colorimetry, the LOD and linear range were 33.89 nM and 10–80 nM. Furthermore, the manufactured sensor has demonstrated exceptional reproducibility, strong stability, anti-interference capabilities, and excellent repeatability for noradrenaline detection. [ABSTRACT FROM AUTHOR]

Dendritic mesoporous silica nanospheres (DMSNs) possess excellent specific surface areas, pore volumes, and extremely accessible internal spaces. DMSNs have experienced high-speed development in the aspects of synthesis techniques, functionalization strategies, and application fields. It is proved that DMSNs own inherent structural superiorities as catalysts, adsorbents, or reaction platforms. Naturally, researchers are enlightened to conceive and attempt to synthesize dendritic mesoporous titania nanospheres (DMTNs) by replacing Si in DMSNs with Ti, in view of the superior activity and catalytic performance from TiO2. Nevertheless, the hydrolysis and condensation rates of the titanium precursors are too fast to develop ideal dendritic textures. To get the goal in a roundabout way, hybrid dendritic mesoporous silica&titania nanospheres (DMSTNs) come into sight. In this work, a series of DMSTNs have been synthesized by the one-pot co-condensation method. For the first time, their morphologies and architectures have been controlled by adjusting the ratio of titanium to silica, stirring speed, reaction temperature, co-solvent, etc. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been utilized to directly reveal their differences. The basic physicochemical properties of DMSTNs with fine topological structures have been compared, covering Fourier Transform Infrared spectroscopy (FT-IR), X-ray diffraction (XRD), N2 adsorption–desorption isotherms, Raman spectrum, X-ray photoelectron spectroscopy (XPS), ultraviolet–visible diffuse reflectance spectroscopy (UV-Vis-DRS), photoluminescence (PL) spectra, etc. Most importantly, these typical DMSTNs can photo-catalytically produce more hydrogen (2.4 ~ 3.6 times) within 1% Pt than that of bare DMSNs under simulated sunlight, owing to Ti in their skeletons. [ABSTRACT FROM AUTHOR]

The photocatalytic performance of high entropy alloy (HEA) and its oxide form (high entropy oxide, HEO) have been evaluated in this study. The HEA, composed of Nb, Ta, Zr, Mo, and W powders, was synthesized through a mechanical alloying process for 120 h. This process was carried out under a high-purity Ar atmosphere to prevent oxidation. Subsequently, the HEA was converted into HEO via a mechano-thermal oxidation method 900 °C for 12 h. The photocatalytic activity of both oxidized and non-oxidized samples was systematically evaluated by degradation of methyl blue (MB) under UV irradiation. Electron dispersive spectroscopy (EDS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used to investigate the structural and chemical features of the alloys. Furthermore, BET surface area analysis and Zeta potential measurements were conducted to understand the alloys' surface properties and stability in aqueous solutions. The results showed that the HEA has a remarkable photodegradation performance of around 58.77% which is two times higher than that observed with the HEO. [ABSTRACT FROM AUTHOR]

Modification of the surfaces of polymeric scaffolds is often required to make the material suitable for specific tissue engineering applications. Physico-chemical properties of scaffolds can be altered using various methods, such as plasma treatment, laser processing, chemical modifications, grafting with nanoparticles, or surface coating. In this paper physico-chemical modification of polycaprolactone (PCL) surface fibers was performed by exposing PCL samples to simultaneous soft X-ray/extreme ultraviolet (SXR/EUV) radiation and low-temperature, SXR/EUV-induced, nitrogen, and oxygen plasmas. The physical and chemical changes on modified PCL surfaces were examined using a scanning electron microscope and X-ray photoelectron spectroscopy, respectively. The effects of physico-chemical scaffold surface changes were verified with biological tests, i.e., MTT assay and immunofluorescence on murine osteoblast cell line (7F2). It was found that exposure of scaffolds to ionizing radiation and low-temperature plasmas induced strong chemical changes on their surface, i.e., appearance of various new chemical groups. Also, smoothing of the surface of PCL fibers, i.e., disappearance or significant reduction of the size of micropores on their fibers was also observed. Increased viability and adhesion of 7F2 osteoblasts on modified PCL samples after 24 h cell culture compared to non-treated PCL was also confirmed. [ABSTRACT FROM AUTHOR]

Organic–inorganic semiconductor interfaces are of utmost importance in many photoelectrochemical applications, including water splitting and photodegradation of pollutants. The current work focuses on the fabrication and characterisation of transition metal-loaded polydopamine (PDA) electropolymerised on the surface of titania nanotubes. The structural studies via X-ray photoelectron spectroscopy and electron microscopy confirmed the catalytic effect of d-metal salts on the formation of the PDA layer during electropolymerisation. Cu and Ni loading leads to a significant enhancement of the visible absorption compared to that of the pristine PDA, also confirmed by the density functional theory calculations. Although the boost is greater for the thickest coatings, an excess amount of polymer suppresses the charge transfer and thus photocurrent generation. Synthesis in acidic conditions—optimal for photosensitisation—provides structures with a strong increase in the photocurrent quantum efficiency in the visible range, equal to 20% at 400 nm. [ABSTRACT FROM AUTHOR]

The synthesis of Bisphenol A Glutaraldehyde Phenolic Resin (BPA-GA PF) was carried out under alkaline conditions using Bisphenol, A (BPA) and Glutaraldehyde (GA) as raw materials, with n-butanol serving as the solvent. Based on the aforementioned information, the researchers prepared modified BPA-GA PF resins by incorporating titanium (Ti), silicon (Si), and boron (B) through a polymer derivative method. This process led to the formation of Ti/Si/B-modified PF resins. By manipulating the proportion of elements in the BPA-GA PF, the modified phenolic resin demonstrated improved capacity for design and processing. The characterization of the modified BPA-GA PF involved the analysis of its transformation process and thermal behavior through the utilization of Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric Analysis (TGA). The presence of B, Ti, and Si elements in the system resulted in the formation of Si–O-B and B-O bonds, as determined. The Ti/Si/B -modified PF exhibited a significant increase in yield. Analysis employing X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) revealed that, following high-temperature annealing, the materials underwent a transformation into Ti/Si/B-modified PF with a highly cross-linked network structure. Oxidation experiments conducted under static conditions demonstrated that the Ti/Si/B-modified BPA-GA PF exhibited significantly greater high-temperature resistance compared to the BPA-GA PF. Among the various options, the Ti/Si/B-modified PF material with a Ti/Si ratio of 1:2 exhibited the most superior resistance to high-temperatures. [ABSTRACT FROM AUTHOR]

The impact of medium- and high-entropy alloy fillers (4E MEA- Al0.25Fe0.25Ni0.25Cu0.25, and 5E HEA-Al0.20Fe0.20Ni0.20Cu0.20Ti0.20) on the microstructures and corrosion behaviour of AA5083 plates, joined through the GTAW process, is investigated. MEA and HEA fillers were fabricated using the CCW method, and ER5356 filler was used for comparison. This study delves into the alloy fillers' influence on the resultant microstructural characteristics and corrosion resistance of the welded joints. XRD results on weld samples showcased the presence of FCC and BCC phases. The weldment EBSD data revealed unique grain morphologies: long columnar grains, coarse grains, and fine equiaxed grains in WZ, HAZ, and BM, respectively. Microstructural investigations of the weldment revealed heterogeneous structures with finely distributed grains and strong bonding between the AA5083 base metal and filler wires, influenced by constitutional elements. MEA and HEA weldments showed no intermetallic compounds or precipitates. In the ambient temperature potentiodynamic polarisation test, HEA's polarisation resistance was 3.76 times greater, while MEA's was 3.15 times higher than ER5356. The higher corrosion resistance is due to grain refinement, increased grain boundaries, and the formation of a strong passive film. Conversely, in the higher-temperature corrosion experiment, the mass loss for the 5E-HEA and MEA weldments was 4.87 and 3.09 times lower than that of the ER5356 weldments. The corroded surface morphology revealed that the ER5356 weldment had deeper pits, while the MEA and 5E-HEA weldments had pits of smaller sizes. The formation of oxidation film layers on the corroded surface improves the corrosion resistance. X-ray photoelectron spectroscopy (XPS) findings showed metal oxide layer depositions for all the weldments. Researchers observed that equimolar MEA and HEA filler wires can increase durability and be employed in shipbuilding sectors. [ABSTRACT FROM AUTHOR]

This paper presents the nickel–cobalt nanoprickly particles (PNi2Co3) composited with graphene nanosheets (GNs) and carbon nanotubes (CNT), prepared via the one-pot hydrothermal method (PNi2Co3/GNs/CNT), as an efficacious nonprecious metal bifunctional electrocatalyst for both oxygen evolution and reduction reactions (OER/ORR). The study employs a comprehensive methodology, incorporating cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Brunauer–Emmett–Teller (BET) analysis to characterize and assess the materials and electrochemical properties investigated in the article. The primary objective was to successfully prepare a bifunctional electrocatalyst, and the PNi2Co3/GNs/CNT material achieved this goal. It exhibited superior OER activity, durability, and resistance to crossover effects, by an overpotential (η) of 480 mV and a Tafel slope of 61 mV dec−1, significantly higher than those obtained for RuO2 nanoparticles (η = 970 mV, Tafel slope = 85 mV dec−1). A similar trend was observed for ORR, where the PNi2Co3/GNs/CNT displayed high activity with an n = 3.93, close to the activity of a Pt/C (20 wt%), commercial catalyst with n = 4. Careful analysis of the EIS results via suitable models, in conjunction with Tafel data, revealed that the enhanced activity originates mainly from two factors: (a) the large surface area of the Ni–Co nanoprickly alloy and graphene sheets, where the CNTs (as a spacer) helped graphene nanosheets to avoid restacking and decreasing the surface area, and (b) the synergistic effect between Ni–Co nanoprickly and carbon components (GNs and CNT) of the composite. [ABSTRACT FROM AUTHOR]

This study explores the capabilities of solvothermally synthesized bismuth telluride (Bi2Te3) hexagonal platelets as a promising anode material for both Li-ion and Na-ion batteries. Bi2Te3 anode material exhibits a high initial discharge capacity of 837 mA h g−1 at a current density of 100 mA g−1 against Li metal whereas, an initial discharge capacity of 678 mA h g−1 is observed at a current density of 20 mA g−1 for the same against the Na metal. The Li- and Na-storage mechanism in Bi2Te3 platelets has been investigated by using both galvanostatic charge–discharge and cyclic voltammetry measurements. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy techniques have been used to examine the structural characteristics, surface morphology, and lattice vibrational modes of Bi2Te3 hexagonal platelets. Further, FTIR spectroscopy was employed to determine the presence of functional groups while X-ray photoelectron spectroscopy was employed for the elemental analysis of Bi2Te3 sample. [ABSTRACT FROM AUTHOR]

The influence of grain refinement by high-pressure torsion (HPT) on the corrosion behavior of CoCrFeNi alloys with varied Cr content was investigated in aqueous 0.5 M H2SO4 and 3.5% NaCl solutions. The results were compared with CoCrFeMnNi alloys. Both the alloys showed a single fcc phase after vacuum melting and HPT. Protective passivation capability and resistance to general corrosion in H2SO4 was higher than that of Fe–Cr alloys and became higher with increasing Cr contents, indicating that high corrosion resistance of Cr-containing HEAs is attributed to the incorporation of Cr with other supporting elements. However, the impact of the nanocrystalline structure by HPT on the general corrosion behavior in the H2SO4 solution was negligibly small while the resistance to the local attack as pitting in NaCl was improved for the CoCrFeNi alloy. This is contrasted with the CoCrFeMnNi alloy, which exhibited negligibly small change by HPT in both NaCl and H2SO4 solutions. X-ray photoelectron spectroscopy indicated the Cr enrichment in passive films, but its degree is smaller regardless of grain size and Mn content, as compared with that of Fe–Cr alloys reported in the literature. The small change in the Cr enrichment in the passive film and the resulting corrosion behavior by grain refinement through HPT could be attributed to an intrinsic nature of HEAs such as sluggish diffusion and intrinsic lattice distortion. The improved resistance to pitting corrosion in CoCrFeNi alloys could be explained by the homogenization effect of the ultrahigh strain deformation, which may not take effect in alloys containing the solute Mn. [ABSTRACT FROM AUTHOR]

The present work aims to examine the reciprocating wear characteristics at elevated temperatures (200 °C, 400 °C, and 600 °C) of CoCrFeNiW0.3 + 5 at% C high entropy alloy coatings, which has been synthesized by atmospheric plasma spraying. The experimental findings pertaining to the worn surface demonstrate that an increase in testing temperature leads to a reduction in wear scar depth. The findings derived from the examination using field emission scanning electron microscopy (FESEM) revealed the existence of wear debris, an adhesive layer, craters, and scratches on the surfaces that were subjected to wear. The examination of worn surfaces using X-ray photoelectron spectroscopy (XPS) has shown the existence of several oxides. The presence of oxides is established while evaluating worn surfaces by Fourier transform infrared spectroscopy (FTIR). The X-ray diffraction (XRD) analysis reveals that the lack of oxide development might perhaps be attributed to the limited width of the worn track. The observed reduction in wear volume loss with increasing testing temperature may be attributable to the reaction arise inside the tribolayer and oxides formation. The energy-dispersive X-ray spectroscopy (EDS) examination of the Al2O3 counter body indicated the presence of a transferred tribofilm. The alloy coating, namely the CoCrFeNiW0.3 + 5 at% C alloy coating, exhibits a decreased mass loss of 9.43 mg and an average coefficient of friction of 0.46 at a test temperature of 600 °C. When the sample is subjected to a wear testing temperature of 600 °C, the wear mass is decreased by 24.37%. The results of this investigation provide promising prospects for practical use in applications requiring high temperature wear resistance. [ABSTRACT FROM AUTHOR]

To improve the utilization efficiency of ozonation in wastewater treatment, a series of perovskite-type Ce-doped LaCoO3 catalysts were designed and fabricated through citrate-assisted solgel method. These catalysts were characterized systematically by transmission electron microscope (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). A heterogeneous catalytic ozonation system was constructed to degrade nitrobenzene (NB) in water using Ce-doped LaCoO3 as catalysts under mild conditions. The results showed that La0.9Ce0.1CoO3 catalyst had the highest catalytic activity and satisfactory stability for the catalytic ozonation reaction. The TOC removal efficiency of NB reached as high as 92.5% in 30 min, which was much higher than the sole ozonation (only 34.1%) in a similar condition. Both the results of the radical quenching experiments and electron paramagnetic resonance (EPR) spin trapping experiments demonstrated that ·OH, O2·−, and 1O2 were all generated in the catalytic ozonation system, among which ·OH played a dominant role in the NB mineralization process. Moreover, La0.9Ce0.1CoO3 catalyst could promote the formation of more ·OH by the cycles of ≡Co3+/≡Co2+ and ≡Ce3+/≡Ce4+, which was the main reason of the higher catalytic efficiency in catalytic ozonation system. The catalytic ozonation system with perovskite-type Ce-doped LaCoO3 catalyst has a potential application in the treatment of refractory organic wastewater. [ABSTRACT FROM AUTHOR]

Three different types of carbon nanomaterials, SWCNTs, MWCNTs and GNPs were prepared, modified, characterized, and their dispersibility behavior in three different solvents was evaluated. The carbon nanotubes were synthesized by using the well-known chemical vapor deposition method and the graphene nanoplatelets by wet physicochemical treatment techniques. Their characterization was accomplished by using various advanced techniques, such as powder X-ray diffraction and Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and N2 adsorption at 77 K. Furthermore, the carbon nanostructures were modified via plasma treatment and wet chemical surface modification in order to enhance their dispersion characteristics, for achieving more homogenous suspensions and therefore to be remained dispersed over a reasonable period of time without any sedimentation. The effect of treatment parameters and the use of different solvents were thoroughly studied mainly by optical methods, but also by using the DIN/EN classified ISO method of oil absorption and UV–Vis spectroscopy. The enhanced dispersion rate is observed in both CNTs and GNPs materials following their surface treatment, especially when using the solvent n-methyl-2-pyrrolidone. The aforementioned studied nanomaterials are perfect candidate fillers for preparing polymeric mixed matrix membranes. [ABSTRACT FROM AUTHOR]

Novel Si3N4/PAN/SiZrOCN ceramic aerogel composites, which have excellent wave transmission functions, were prepared through electrospinning, freeze-drying, and high-temperature pyrolysis. Polyvinyl alcohol was used as the aerogel carbon skeleton, polystyrene served as the pore-forming substance, Si3N4/PAN fiber was used as the reinforcement material. The pore size distribution and dielectric properties of the composites were systematically studied at different pyrolysis temperatures. An increase in pyrolysis temperatures led to a decrease in the specific surface area and dielectric constant. Fourier infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction were employed to investigate the polymerization mechanism and ceramic process of the precursor. The Brunauer–Emmett–Teller test revealed that the maximum specific surface area of Si3N4/PAN/SiZrOCN ceramic aerogel composites was 109.261 m2/g, and the average pore size was 4.56 nm when sintered at 600 °C. The dielectric properties test results showed a dielectric constant ranging between 3.1 and 3.7 and a dielectric loss tangent value between 2.6 × 10–3 and 1.6 × 10–2 for the sample. Si3N4/PAN/SiZrOCN ceramic aerogel composites exhibited excellent dielectric properties at room temperature and demonstrated exceptional dielectric stability across different frequency bands (1.8–18.0 GHz), making them a potential high-temperature wave-transmittance material. [ABSTRACT FROM AUTHOR]

Chemical plants which process highly carbonaceous gases at elevated temperatures are prone to catastrophic corrosion by metal dusting. Typically, commercial alloys with high amounts of protective oxide scale formers (Cr, Al, and Si) are used in these environments. However, scale failure is still frequently observed after an incubation time initiating pits. In this study, the microstructure and subsequent metal dusting-induced failure of the oxide scale on the commercial Ni-based alloy 601 was analyzed. Samples were exposed in different aggressive metal dusting gases and characterized using metallographic cross sections, electron beam microanalysis (EPMA), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and transmission electron microscopy (TEM). A thin and protective chromia scale formed in some regions with a continuous silica layer below. Across most of the alloy 601 surfaces, internal oxidation of Al could be linked to metallic particles in the outer scale. Additionally, MnCr2O4 was observed in the outer scale. Together with pores in the chromia, the spinel and metallic particles in the outer scale combined to provide pathways for carbon ingress. After exposure in a gas with a higher driving force for carbon deposition, a higher amount of carbon was incorporated in the growing oxide scale, resulting in earlier scale failure and metal dusting pit initiation. [ABSTRACT FROM AUTHOR]

The interesting chemical and physical properties of microporous zeolites have led to their use in numerous industrial applications, such as adsorbents, ion exchangers, and catalysts, increasing the worldwide consumption of these materials annually. However, the development of synthetic zeolites usually involves the use of expensive chemical reagents; therefore, the use of alternative sources of Si and/or Al, such as minerals and waste streams, has gained attention over the past few years owing to the benefits in production costs and decreasing environmental burden. In this study, we report the synthesis of single-phase small-pore NaP zeolites via alkaline hydrothermal treatment (HT) using natural clinoptilolite (CLIP) as the Si and Al source. The synthesized zeolites were analyzed using X-ray diffraction, electron microscopy, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy. The results showed that the variations in molar concentration (1 and 2 M), crystallization time (24 and 39 h), and crystallization temperature (90, 105, and 110 °C) play a major role in obtaining two types of NaP isomorphs (NaP1 and NaP2), which feature a flexible framework, where the synthesis parameters of 1 M, 24 h, and 90 °C led to the formation of a single-phase NaP1 zeolite with high purity. These results demonstrate the feasibility of developing sustainable synthesis processes from low-cost and abundant raw materials to produce high-value-added synthetic zeolites as alternatives to traditional chemical reagent-based synthesis methods. [ABSTRACT FROM AUTHOR]

The ZnWO4/TiO2/MoS2 (ZTM) ternary composite catalyst was prepared based on the excellent performance binary photocatalyst semiconductor ZnWO4/TiO2 composite powder. The application potential of the photocatalyst to decolorization of methylene blue (MB) dyes under sunlight was studied. The composites were characterized by X-ray diffraction technique (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The properties of the composites were tested with BET methods, ultraviolet–visible (UV–Vis) spectrophotometer and photoluminescence (PL) techniques. The experimental results indicate that the ternary catalyst has a nanorod-like morphology, better crystallinity, and large specific surface area. The specific surface area of ZTM-0.5 semiconductor photocatalyst is 2.54 times that of pure ZnWO4 and 1.83 times that of binary semiconductor photocatalyst. Compared with pure ZnWO4, the band gap of ZnWO4 is significantly reduced, and it has excellent photocatalytic properties, and the degradation rate of MB can reach 99%. The composite of MoS2 also inhibits the composite of photogenerated electron–hole pairs, improves the concentration of photocatalytic intermediates, not only improves the photocatalytic activity, but also improves the stability of the photocatalyst. After three cycles of degradation experiments, the degradation efficiency of ZTM-0.5 photocatalyst remains at 65%. The main radical affecting the photocatalysis through the trapping agent benzoquinone test is the superoxide radicals (·O2−). Possible photocatalytic reaction mechanism of ZnWO4/TiO2/MoS2 composite. The ZnWO4/TiO2/MoS2 ternary composite catalyst was prepared based on the excellent performance binary photocatalyst semiconductor ZnWO4/TiO2 composite powder. The phase composition, microstructure, and photocatalytic properties of the molybdenum disulfide composites at different mass percentages were investigated. [ABSTRACT FROM AUTHOR]

Hand-tungsten inert gas welding is employed using Inconel 82 as a filler metal to weld T92 ferritic steel and HR3C austenitic steel. The microstructures of the joints are analyzed via optical and transmission electron microscopy. The corrosion resistance of the joints is evaluated via electrochemical and immersion corrosion tests, whereas the corrosion products and passive films are analyzed using scanning electron microscopy and X-ray photoelectron spectroscopy. The results show that the weld metal region of the T92/HR3C dissimilar metal joint formed a dense passivation film containing Cr2O3 and NiO owing to the highest Cr and Ni contents, which effectively prevented the entry of chloride ions into the matrix, thus impeding corrosion and providing optimal corrosion resistance. Compared to the base material of T92, the heat-affected zone of T92 shows fine austenite grains and subgrain structures, as well as a relatively thick Cr2O3 passivation film, which improved the corrosion resistance. [ABSTRACT FROM AUTHOR]

With acrylamide (AM), methacryloxyethyltrimethyl ammonium chloride, polyethyleneimine ethoxylated (PEI), and graphene oxide (GO) as the raw materials, an amino-functionalized GO-based recyclable composite aerogel (CPAM/PEI/GO, CPAM = cationic polyacrylamide) was constructed by a mild method. In order to verify successful preparation of the composite aerogel, it was characterized by Fourier infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. Since CPAM/PEI/GO had negative charge on the surface, methyl orange (MO), an anionic dye, was chosen as the adsorption molecule to study adsorption performance of the aerogel. The results showed that CPAM/PEI/GO possessed efficient adsorption performance toward MO, and the equilibrium adsorption capacity could attain 677.55 mg/g at 303 K. The adsorption process for CPAM/PEI/GO toward MO could be well simulated by pseudo-second-order kinetic and Langmuir adsorption model, and the adsorption was a spontaneous process. The main driving forces of adsorption process were hydrogen bonding, π–π conjugate interaction, and electrostatic interaction. Even after six adsorption–desorption cycles, the equilibrium adsorption capacity of CPAM/PEI/GO aerogel still could retain 536.99 mg/g, which indicated that the aerogel exhibited good regenerability. The composite aerogel might provide a new inspiration for the preparation of amino-functionalized GO-based aerogels and broaden their application field in wastewater treatment. [ABSTRACT FROM AUTHOR]

This work reports a whole green two-step approach for the synthesis of novel catalysts for efficient CO2 conversion. A conductive carbon support was firstly obtained via pyrolysis of cellulose nanocrystals (CNCs), and the carbon surface was successively decorated with tin sulfide (SnS) through a microwave-assisted hydrothermal process. The morphology and carbon structure were characterized by field emission scanning electron microscopy and Raman spectroscopy, and the presence of SnS decoration was confirmed by X-ray photoelectron spectroscopy and X-ray diffraction analyses. The SnS supported on CNC-derived carbon shows enhanced catalytic activity for the CO2 conversion to formate (HCOO−). Good selectivity of 86% and high partial current density of 55 mA cm−2 are reached at − 1.0 V vs. reversible hydrogen electrode in KHCO3 electrolyte. Additionally, the mass activity of the composite catalyst achieves a value as high as 262.9 mA mgSn−1 for HCOO− formation, demonstrating good utilization efficiency of Sn metal. In this work, the low-cost CNC-derived carbon is evidenced to be easily decorated with metal species and thus shows high versatility and tailorability. Incorporating metal species with conductive high-surface carbon supports represents an effective strategy to realize active and stable electrocatalysts, allowing efficient utilization of metals especially the raw and precious ones. [ABSTRACT FROM AUTHOR]

For the photocatalytic degradation of the crystal violet (CV) and methyl orange (MO) dyes 5% Ni(II) doped ZrO2 (Ni–ZrO2) was synthesized from low-cost precipitation method and characterized by different instrumental methods like X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), and X-ray photoelectron spectroscopy (XPS). The XRD pattern showed that the synthesized Ni–ZrO2 nanomaterial was composed of monoclinic (m-ZrO2) and tetragonal (t-ZrO2) phases, with the dominance of m-ZrO2 peaks. The crystallographic phase was confirmed by HR-TEM. The SEM pictures showed porous ball-like formations in Ni–ZrO2. EDAX confirmed the elemental composition, and XPS validated the chemical and electronic state of the atoms within a material. After 110 min of exposure to the catalyst, Ni–ZrO2 demonstrated 97.5% degradation of CV dye and 96.25% degradation of MO dye. For photocatalytic degradation of CV and MO dyes using Ni–ZrO2, parameters such as catalyse dose, pH, light and dark, initial dye concentration, contact time, and reusability test were investigated. The degradation efficiency was found to be greater than 90% after four cycles. [ABSTRACT FROM AUTHOR]

The solid-state electrolytes have attractive properties for electrochromic (EC) devices and battery industries. Li+ ion is the most applied and investigated carrier ion in this field together with less commonly ions Mg2+, Na+ H+ and Al3+. In this study, we have investigated Al3+ solid electrolytes for WO3 based EC devices as alternative to Li+ ions. We have fabricated a series of AlSiOx thin films by applying different target powers of 0–15 W by magnetron sputtering method. The resulting films were characterized by Grazing incidence X-ray diffraction, atomic force microscopy, scanning electron microscopy, energy disperse spectroscopy, ultraviolet–visible-infrared spectrophotometer, X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy (EIS). All samples showed high transparency in the visible range (~ 90%) while the transparency decreased about 10% in the near infrared region. Analysis of EIS data by Kramers–Kronig and Voigt models showed that some of the films have good ionic conductivity. The ionic conductivities of films grown with 10 W, 13 W and 15 W Al target powers were 1.54 × 10–6, 5.68 × 10–7 and 2.72 × 10–8 S/cm, respectively. The results indicate that AlSiOx solid electrolytes are promising for EC applications. [ABSTRACT FROM AUTHOR]

This work describes the synthesis, characterization, and application of nanoneedle-shaped CuONPS/Cdot(N) nanostructures obtained by direct reaction between Cu(NO3)2 and nitrogen-doped carbon quantum dots (Cdot(N)). The CDot(N) obtained from oleylamine using the electrochemical technique of chronoamperometry was used as catalysts and directing agents in synthesizing CuONPS/Cdot(N) nanostructures. The CuONPS/Cdot(N) nanostructures were characterized using transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet spectroscopy (UV–Vis), infrared spectroscopy (FTIR), and electrochemical techniques. HR-TEM and XPS analysis has shown that CuONPS/Cdot(N) nanostructures are constituted for both CuO and Cu2O nanospecies. The printed carbon electrode was modified with CuONPS/Cdot(N) nanostructures. It was used to determine the pesticide glyphosate in PBS, pH 5.5, at a potential of E = − 0.02 V, using the differential pulse voltammetry technique with a detection limit of 11.6 nMol L−1. The printed carbon electrode was modified with CuNPS/Cdot(N) nanostructures and was also used to determine pesticides in real water samples with good performance. [ABSTRACT FROM AUTHOR]

Tri-s-triazine heterostructures have been prepared using different mass ratios of g-C3N4, melem, mellitic trianhydride (MTA), and graphene as precursors. The heterostructures were characterized by elemental analysis (CHN), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), specific surface area, thermogravimetric analysis (TGA/DTA), and diffuse reflection spectroscopy (DRS). The formation of reactive species under light irradiation was verified by electron paramagnetic resonance (EPR). Hydrogen evolution reactions (HER) were conducted in a potentiostat. According to the results, the heterostructures produced with melem and MTA are formed by mellitic triimide (MTI) and tri-s-triazine species (g-C3N4 and melem) layers. EPR spin-trapping experiments showed hydroxyl radicals formation when the materials were irradiated, which, however, are produced indirectly by superoxide anion radicals. The increased amount of MTI is detrimental to photocatalytic activity. On the other hand, we proved that the increase in the MTA content increased the HER. The results showed that modulation of MTI content in intramolecular tri-s-triazine heterostructures is a promising approach for producing materials for photo- and electrocatalysis. Metal-free hybrid photocatalysts of tri-s-triazine species (melem and g-C3N4), graphene, and mellitic trianhydride (MTA) were synthesized: g-g, g-m, and g-g-m. The mellitic triimide (melem and MTA) ratio and graphene as a cocatalyst in heterostructures for generating reactive oxygen species (in visible light) and hydrogen evolution reactions were evaluated. [ABSTRACT FROM AUTHOR]

This work mainly focuses on the generation of white light from sodium antimony zinc borate (BNZS) glasses as well as by introducing silver ions into the glass matrix through the Na+–Ag+ ion-exchange method. The glasses of 40B2O3–10Na2O–(50−x) ZnO–xSb2O3 (in mol%) where x = 0, 10, 20, 30, and 40 were prepared through melt quenching technique and are characterised by XRD, UV–VIS–NIR absorption spectra, photoluminescence, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) techniques. CIE 1931 chromaticity colour coordinates for all base glasses without silver fall within the blue region. Based on the ion-exchange duration, the colour coordinates shifted from blue to white light with the introduction of silver ions into the glass. This is due to the formation of silver nanoclusters of various dimensions and concentrations by different reduction and aggregation mechanisms in the glass matrix. The mechanism behind the evolution of white light generation has been analysed using the Raman and XPS spectral analysis. Traditional phosphors containing rare earth ions are widely used in displays, lasers, optical amplifiers, and white light-emitting diodes, having limitations such as narrow emission bands, low thermal stability, and their scarcity as well as high cost. Hence, this paper explores the generation of white light from rare earth-free glasses by embedding optically active nanoparticles into it and postmodifying its properties. [ABSTRACT FROM AUTHOR]

The integration of two-dimensional molybdenum disulfide (MoS 2 ) and reduced graphene oxide (rGO) into a polypyrrole (PPy) matrix appears to be a productive method for improving the structural, optical, and electrochemical properties of pure PPy. rGO-PPy-MoS 2 composite was synthesized via in-situ polymerization process. The formation of the composite was confirmed using X-ray diffraction, Fourier transform infrared, and Raman investigations. Field emission scanning electron microscopy, transmission electron microscopy, and EDX were utilized to analyze the surface morphology and elemental analyses of rGO-PPy-MoS 2 composite, because of their strong charge transport properties, the composites display both micro and meso-porosity with increased surface area. Elemental purity and composition of the synthesized materials were characterized through X-ray photoelectron spectroscopy. The optimized composites' band gap was 1.63 eV, with refractive index of 2.45 showed good optical conductivity and their photoluminescence characteristics reveal blue emission at 445 nm with color purity of 77.1%. The composite's electrochemical characteristics provide an excellent potential response in the 0–1 V range. The specific capacitance of rGO-PPy-MoS 2 showed 235.6 F/g with maximum power density of 4300 W/kg and energy density of 11.61 Wh/kg. All of these findings point to rGO-PPy-MoS 2 composite as a potential emissive layer material with suitable materials for supercapacitor application. [ABSTRACT FROM AUTHOR]

The low Li+ diffusivity and electronic conductivity of LiFePO4 (LFP) cathode materials seriously hinder the application in lithium-ion batteries (LIBs) at high-rate. To break these limits, we synthesized the La3+ or/and Y3+-doped LiFePO4 cathode materials with 2-3 nm thick carbon layer prepared using ascorbic acid by hydrothermal method. The material structure was analyzed and characterized by Fourier transform infrared spectroscopy (FT-IR), x-ray spectroscopy (XRD), x-ray photoelectron spectroscopy (XPS), Raman spectroscopy (Raman), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical performance of the materials was studied by electrochemical workstation and battery tester. It was found that the La3+ and Y3+ co-doped LiFePO4 (La·Y-LFP/C) reached a high specific capacity of 160.56 mAh g−1 at 0.2C and still had a specific capacity of 138.27 mAh g−1 after 100 cycles at 5C. The Li+ diffusivity (DLi+) of La·Y-LFP/C was 3.68 × 10–13 cm2 s−1. It was believed that doping La3+ or/and Y3+ can enlarge the lattice of LiFePO4 to widen the migration path for Li+, and help to reduce the electrostatic binding of surrounding atoms to Li+. The calculation results of band gap and state density further confirmed that doping of La3+ or/and Y3+ increased the charge carrier concentration of the material to achieve better Li+ diffusivity and electron conductivity of LiFePO4. Therefore, the La3+ and Y3+ co-doped LiFePO4 cathode material has a good application prospect in high-power LIBs with outstanding electrochemical performance. [ABSTRACT FROM AUTHOR]

The environmentally friendly luminescent sensing materials are desired for detection of heavy metal ions. Herein, two kinds of fluorescent nanomaterials, carbon dots (CDs-1) and N-doped carbon dots (CDs-2) were designed and synthesized as effectively sensors for simultaneous detection of Fe3+ and Cu2+ ions. A simple one-step hydrothermal synthesis was adopted by using cost-effective precursor humic acid (HA) as a carbon source and ammonium hydroxide as a nitrogen source. Photoluminescence (PL) spectra and TEM images reveal the distinct structure and property of these two CDs, in which CDs-1 display blue fluorescence with the average diameter of about 1.73 nm, while CDs-2 possess larger size (av. 2.41 nm) because of the larger conjugated structures and exhibit green fluorescence. The successful doping of N on the surface of CDs-2 was confirmed by characterizations of X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR), which endows CDs-2 improved detection performance than that of CDs-1. CDs-2 could selectively and sensitively detect iron(III) and copper(II) ions, and the limit of detection (LOD) can reach 73 nM and 61 nM with a liner range from 0 to 20 μM and 0 to 50 μM, respectively. The fluorescence static quenching effect and the formation of the ground-state complex may explain the quenching mechanism of CDs-2 in this process. This work demonstrates the more possibilities of applying the low-cost waste and developing high-efficiency CDs-based luminescent sensors. [ABSTRACT FROM AUTHOR]

Aluminum oxide is an important ceramic material for coatings and catalyst support for high-temperature applications. In this work, spherical aluminum oxide (AlOx) nanoparticles (NPs) are synthesized via the thermal decomposition of aluminum oleate using oleic acid as a stabilizing agent. X-ray diffraction analysis confirms its crystallization to γ-Al2O3 and α-Al2O3 after annealing at 700 and 1100 °C, respectively, revealing their gradual phase transition. Morphological and crystallinity changes of spherical nanoparticles upon annealing were investigated by transmission electron microscopy. The chemical composition and phase transitions to Al2O3 NPs were supported by X-ray photoelectron spectroscopy as a function of temperature. Monolayer assembly of as-synthesized NPs onto quartz substrate was performed using organic linker molecules (11-phosphonoundecanoic acid), which was confirmed by atomic force microscopy imaging. The optical band gap of the monolayer assembly was evaluated after annealing at different temperatures along with transmittance properties to compare with the current literature by UV–visible spectroscopy. [ABSTRACT FROM AUTHOR]

A newly designed smart self-healing epoxy coating system comprised of modified halloysite nanotubes (HNTs) having capping is proposed for corrosion protection of steel. In the first step, HNTs were loaded with 8-hydroxyquinoline (8HQ), used as a corrosion inhibitor. Then the HNTs were sealed/capped using cobalt (II), aiming for an efficient and controlled release of the loaded inhibitor. The smart coatings were developed by reinforcing loaded HNTs into the epoxy matrix. The structural, thermal, mechanical, and electrochemical properties of capped modified HNTs and smart coatings were studied using various techniques. UV–Vis analysis depicted that the capping of the metal-inhibitor complex was decomposed at acidic pH resulting in a controlled release of the loaded inhibitor into HNTs. Electrochemical impedance spectroscopic (EIS) analysis of blank and smart coatings demonstrated that the low-frequency impedance modulus of smart coatings is 109 Ω.cm2 for 20 days compared to blank coatings (105 Ω.cm2), reflecting their excellent corrosion inhibition performance. The superior corrosion protection properties of these smart coatings can be ascribed to the controlled and efficient release of the loaded inhibitor from the capped HNTs. Finally, X-ray photoelectron spectroscopy (XPS) analysis of the steel substrate after the corrosion analysis revealed the adsorption of 8HQ on the steel surface, confirming the formation of iron complex due to the release of loaded inhibitor. This work demonstrated the adeptness of 8HQ in mitigating the corrosion due to the controlled and effective release of the inhibitor from capped HNTs because of dissociation of the metal-inhibitor complex (Co-8HQ).Kindly check and confirm the authors names are correctly identified.Checked [ABSTRACT FROM AUTHOR]

Bimetallic MOFs offer many advantageous properties rather than monometallic MOFs useful for variety of applications including energy storage and conversion, catalysis, gas separation, sensing, etc. Desired morphology with precise control of crystal size is of utmost importance for specific applications. Microfluidics-incorporated continuous synthesis is demonstrated for bimetallic ZIF-8/67 exhibiting significant nanocrystallinity, porosity and surface area. The microfluidic approach of synthesizing MOF is found very time-efficient in comparison with the conventional techniques. Bimetallic ZIF-8/67 samples were synthesized at different reaction conditions, without adding capping agents and modulators, followed by sophisticated characterization techniques including powder X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, Brunauer–Emmett–Teller analysis and Fourier transform infrared spectroscopy. [ABSTRACT FROM AUTHOR]

In this study, a hybrid organic–inorganic material based on polypyrrole (PPy), graphene nanoplatelets (GNPs), and bismuth oxide nanoparticles (Bi2O3) was developed to overcome the limitations of organic materials' thermoelectric (TE) conversion efficiency. The GNPs were decorated with Bi2O3 nanoparticles using a simple and effective method based on infrared irradiation and diazonium chemistry. The synthesized nanocomposites were characterized using various techniques such as X-ray diffraction, Transmission electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy to examine the structural and physical properties. The results of this study showed a promising improvement in electrical conductivity (σ) and Seebeck coefficient (S) of PPy/GNPs-Bi2O3 compared to pure PPy, attributed to the π–π stacking between PPy chains and GNPs surface. Bi2O3 enhances the TE behavior of the nanocomposite by improving charge transport and binding both components (PPy and GNPs). At room temperature, the power factor was found to be 11 times higher (1 µW m−1 K−2) compared to pure PPy. Further exploration at high temperatures could result in higher TE performance. [ABSTRACT FROM AUTHOR]

In this paper, the effects of nitrogen doping and oxygen vacancies on thermoelectric properties of Pt/N-doped ITO thin film thermocouples were discussed in detail from the perspective of thermodynamics and kinetics based on first-principles and experiments. The atomic structure and bonding characteristics of ITO and N-doped ITO were investigated by X-ray diffraction and X-ray photoelectron spectroscopy. The calculation results show that nitrogen doping makes the charge transfer to the Sn-N bond and produces anti-bonding states to the nearest neighbor Sn–O bond, so that the repair of oxygen vacancies in N-doped ITO requires a higher activation energy than ITO. The effects of band structure, carrier concentration and carrier effective mass on the Seebeck coefficients of ITO and N-doped ITO were further discussed in detail. Finally, Pt/ITO and Pt/N-doped ITO thin film thermocouples were fabricated on the Al2O3 substrates by magnetron sputtering to verify their thermoelectric stability. The calibration results also proved that N-doped ITO has higher thermoelectric stability than ITO. [ABSTRACT FROM AUTHOR]

In this work, the corrosion behavior and mechanism of X70 steel induced by soluble extracellular polymeric substances (s-EPS) extracted from Streptococcusmutans (S.mutans) and sodium molybdate as the mixed corrosion inhibitor in 3.5 wt% NaCl solution were investigated. Results of electrochemical measurements showed that the inhibition efficiency of single s-EPS or sodium molybdate increased with increase in concentration of inhibitor but the inhibition efficiency was not too high, while a synergistic effect existed when s-EPS and sodium molybdate were combined together to prevent X70 steel corrosion. The synergistic effect increased with increasing the concentration of s-EPS from 10 to 40 mg/L in the presence of 50 mg/L sodium molybdate, and the synergistic parameter can achieve 5.46. The mixed inhibitors simultaneously inhibited the anodic and cathodic corrosion of X70 steel clearly, which greatly promoted the activation energy of the corrosion reaction. Results from X-ray photoelectron spectroscopy, atomic force microscopy, and field emission scanning electron microscopy demonstrated that co-adsorption of s-EPS and [(OH)4OMo–O–MoO(OH)4]2− led to the formation of a more homogeneous and protective film on the surface of X70 steel. All the adsorption of single and mixed inhibitors followed the Langmuir adsorption model according to the thermodynamic analysis. [ABSTRACT FROM AUTHOR]

This work investigated the improved electrocatalytic performance of PdSn nanoparticle-impregnated NiTiO3 heterostructured nanocomposites. The electrocatalyst PdSn uses NiTiO3 as active support material for methanol oxidation. The PdSn-NiTiO3 was prepared by a microwave-assisted polyol method with four different loadings of Sn with respect to Pd. The NiTiO3 possessed a rhombohedral-structured ilmenite crystalline phase, and the PdSn nanoparticles had the cubic phase. The average particle size of PdSn nanoparticles was 9 nm. The X-ray photoelectron spectroscopy has shown two oxidation states for the cations in NiTiO3, which has left its surface with oxygen vacancies. Electrochemical tests have demonstrated that the PdSn-NiTiO3/C electrocatalyst exhibited good electrocatalytic activity and stability for methanol oxidation in an alkaline medium. Of the four combinations tested, the Pd0.4Sn0.6-NT has performed the best electrocatalytic activity for methanol oxidation due to its high current density and better stability. [ABSTRACT FROM AUTHOR]

A new type of waterborne acrylic resin was prepared by the solution polymerization with octafluoroamyl methacrylate (OF-PMA), 2-butoxy ethanol, and acrylic monomers as raw materials and N, N-dimethyl ethanolamine as pH regulator. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy showed that the OF-PMA monomers were successfully grafted onto the resin. The effects of the addition mode and content of OF-PMA on the properties of waterborne acrylic resin were studied. The properties of waterborne acrylic polymer and its coating were tested by a thermogravimetric analyzer, an optical contact angle measuring instrument, and a tensile testing machine. The results showed that after the introduction of OF-PMA monomer into acrylic resin, the tensile strength of the resin was increased by 14.31 MPa. Moreover, the water resistance and heat resistance of resin coating were also improved obviously and the as-modified resin coating exhibited better fullness, adhesion of Gt0, and the hardness of 4H. The novel acrylic resin exhibits a potential application prospect in the fields of waterborne wood coatings. [ABSTRACT FROM AUTHOR]

Hardened 58Ni39Ti3Hf possesses a superior resistance to quenching cracking and spall-type surface fatigue as compared to 60NiTi, which makes it considered as an alternative for this binary intermetallic. Nonetheless, it is still a lack of deep understanding of how the microstructure, grain distribution, and surface properties of 58Ni39Ti3Hf differ from those of 60NiTi. In this work, combined analysis methods of X-ray diffraction (XRD), electron backscatter diffraction (EBSD), and transmission electron microscope (TEM) were conducted to systematically characterize the phase composition, microstructure, and grain distribution. Nanoindentation test was carried out to study the mechanical properties of surface. The growth of passive film in seawater was analyzed using X-ray photoelectron spectroscopy (XPS). Finally, electrochemical impedance spectroscopy (EIS) measurement before, during, and after the tribocorrosion test was performed to evaluate the corrosion resistance of these two alloys when served in different conditions. 58Ni39Ti3Hf was found to have better corrosion and mechanical properties than 60NiTi within the range of this experiment, and the involved mechanism was discussed in detail. [ABSTRACT FROM AUTHOR]

Polyvinylidene fluoride (PVDF) membranes were surface modified via a simple coating method for improvement of the hydrophilicity performance. In this work, a hydrophilic modified TA/PVDF membrane was prepared by depositing tannic acid (TA). Then, Ethylenediamine (ED) and succinic acid (SA) were grafted onto the surface of the TA coating to prepare TA/ED/PVDF and TA/ED/SA/PVDF membranes. The surface chemical compositions of the modified membrane were investigated by Fourier transform infrared and X-ray photoelectron spectroscopy, and the surface topography of the modified membrane was studied using scanning electron microscopy and atomic force microscopy. Compared with the pristine membrane, the modified membrane has good hydrophilicity and permeability. The water contact angle and water flux of TA/ED/SA/PVDF membrane are 43.3° and 143.8 L·m−2·h−1, respectively. When TA/ED/SA/PVDF membrane was used to separate (Bisphenol A) BPA and (Tetracycline) TC, the rejection ratios reached 86.3% and 91.7%. In addition, the influence of membrane surface charge on the rejection ratio of TC solution was discussed. The results showed that by increasing the pH of the solution from 4 to 10, the retention ratio of TA/ED/SA/PVDF membrane for TC solution increased from 88.8 to 94.4%. In the cycle test, the TA/ED/SA/PVDF membrane has good antifouling performance after three cycles, and its Flux recovery rate reached 89.9%. These results indicated a great application potential of the TA/ED/SA/PVDF modified membrane for water purification, especially antibiotics wastewater treatment. [ABSTRACT FROM AUTHOR]

A facile strategy for preparing Mn3O4 nanoparticles by a soft template method in water was reported. The poly(vinyl alcohol) (PVA) hydrogel, which was used both as template and reducing agent, underwent an in situ reduction reaction with KMnO4, so that the precursor nanoparticles could be uniformly dispersed in the hydrogel. The size and chemical structure of prepared Mn3O4 nanoparticles was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), while the N2 adsorption/desorption isotherm was carried out to determine its surface area. The prepared Mn3O4 nanoparticles with different sizes had good ability for Fenton-like degradation of methylene blue (MB). Their degradation ability was enhanced with the decrease in particle size. The Mn3O4 nanoparticles with minimum size of 8 nm showed the 99.0% degradation efficiency for MB (40 mg/L, 40 mL) with 6 wt% H2O2 as oxidant in 60 min, which reached the state-of-the-art activity for Mn3O4 nanomaterials. [ABSTRACT FROM AUTHOR]

It is well known that poor wettability at the interface between the Al matrix and the reinforcing phase is a technical bottleneck in the development of aluminum matrix composites. A nitrogen-induced self-forming Al composite (NISFAC) process was developed, which is a novel concept of a composite manufacturing process that does not require vacuum or external pressure. This process employs an exothermic reaction accompanying the nitridation of Al, and the heat dissipated from the reaction enables the local melting and self-sintering of the Al powder. In this study, X-ray photoelectron spectroscopy (XPS) analysis was employed to investigate the compositional changes in monolithic SiC particles and the Al/SiC mixture during heating at 700 °C for 1 h in air, argon, and nitrogen atmospheres, respectively. In addition, XPS results were used to examine the mechanism for the surface modification of Al and SiC particles during the NISFAC process and to understand why self-sintering only occurs in a nitrogen atmosphere. [ABSTRACT FROM AUTHOR]