Diamond and Related Materials最新文献

Graphene oxide (GO) is of great interest due to its unique structure and properties and potential applications, including water purification. In this work, we report the synthesis of GO samples with different oxidation degree from two different sources of graphite using Hummers method. Natural flake graphite with a high degree of crystallinity, and synthetic fine powder graphite were used. All produced materials were characterized by CHNS analysis, X-Ray Diffractive analysis (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). It was shown that the oxidation process for natural and synthetic graphite sources proceeds in different ways. The factors, affecting for the structure and properties of GO are the degree of crystallinity and the lateral size of the graphite flakes. The sorption activity of underoxidized, normally oxidized and overoxidized GO was compared toward the methylene blue (MB) dye in aqueous solution. The most efficient sorption was registered for GO produced from synthetic graphite with the use of 2.0 and 4.5 wt. eq. KMnO₄. The sorbents removed 94 % and 100 % of MB from the solution, respectively, in approximately 10 min. Our results reveal that the structure and sorption properties of GO can be tuned by varying the oxidation degree as well as the graphite source, which may open the way to new developments in the GO-based materials applications.

In this study, DLC coatings with varying thicknesses of CrC interlayers were fabricated on the surface of TC4 alloy by regulating the flow rate of C₂H₂. The effects of the interlayer layer on the microstructure, mechanical properties, corrosion resistance, and tribocorrosion resistance of DLC coatings were systematically investigated. The results show that as the C₂H₂ flow rate increases, the CrC interlayer exhibits the structure transitions from columnar crystals to amorphous, resulting in improved hardness. The hardness of the CrC40 interlayer reaches 17.2 GPa, significantly higher than the 9.3 GPa of the Cr underlayer. The CrC interlayer notably enhances the mechanical properties and adhesion strength of DLC coatings. The corrosion current density of the CrC40/DLC coating is 3.07 × 10⁻⁸ A/cm², significantly lower than that of the DLC coating with only a Cr underlayer. Under high load conditions of 20 N, the tribocorrosion rate of the CrC40/DLC coating is reduced to 2.09 × 10⁻⁷ mm³.(N.m)⁻¹, representing a significant decrease of 93.9 % compared to the DLC coating. The CrC40/DLC coating exhibits strong adhesion strength, appropriate internal stress and a relatively hard CrC40 interlayer, showing exceptional tribocorrosion resistance.

This research aims to investigate the synergistic effects of grafting flexible fractions and incorporating reinforcing fillers in polypropylene (PP) matrix. The primary objective is to establish an experimental methodology for preparing and characterizing Polypropylene / Poly(Propylene-Glycol) Acrylate / Glycidyl Methacrylate (PP/PPGA/GMA) composites loaded with graphite oxide (GtO).

The process of oxidizing natural graphite powder using a mixture of sulfuric acid and nitric acid was validated through various analytical techniques including IRTF, AFM, DRX, XRF and ATG. The grafting reaction of PPGA and GMA on polypropylene and the incorporation of graphite oxide with varying levels were carried out in the melt state in a Brabender internal mixer; Dicumyl peroxide (DCP) was used as a radical initiator. A comprehensive assessment of the obtained materials was conducted through conventional analyses encompassing mechanical properties (tensile and impact), thermal behaviors (ATG and DSC), morphological characteristics (SEM) and the chemical state of film surfaces (Contact angle).

The investigation revealed two key outcomes. Firstly, it showcased the grafting effect of PP on the polymer's morphology and properties. Secondly, it underscored the consequential impact of incorporating graphite oxide on the overall behavior of produced materials.

To address the challenges posed by the significant thermal stress and limited affinity of diamond coatings on copper (Cu) substrates, we developed a method combining femtosecond (fs) laser texturing with the application of a nickel (Ni) interlayer. This technique was utilized for adhesion enhancement of diamond coatings on Cu. By varying the deposition duration and microgrid depth through multiple fs laser scanning passes, it is possible to attain well-adhered diamond coatings on Cu substrates. These coatings demonstrate an outstanding quality factor of 93.4% and an average grain size of 5.5 μm. The enhanced adhesion results from the synergistic reinforcement of the mechanical interlock and anchoring mechanisms facilitated by the textured surface, further bolstered by the presence of the Ni interlayer. Moreover, the shape of the texture significantly influences the deposition outcome. Single-crystal diamonds with an average grain size of 10 μm were achieved on sharp microgrids at a substrate temperature of 550 °C. This work is expected to offer a general approach for deposition of diamond coatings on metallic materials with enhanced adhesion.

Environmental safety is a major concern of today's world, and it has attracted the attention of the scientific research community. The environment gets contaminated due to various toxic drugs and pharmaceutical toxins coming from different sources. Therefore, removing these toxins is necessary for making the environment greener and safer. Nanomaterials are excellent candidates for adsorption and removal of harmful materials due to their unique properties. Herein we have studied self-assembled nanotube based on belt[12]pyridine (2-(12BPy)) as an adsorbent for the removal of antituberculosis drugs i.e. isoniazid (INZ) and pyrazinamide (PZA). The adsorption ability is studied by considering the adsorption energy (E_ads), non-covalent interaction index analysis (NCI), quantum theory of atoms in molecules (QTAIM), energy decomposition analysis (EDA), charge transfer via natural bond orbital analysis (NBO) and electron localization function (ELF), and dipole moment. The results indicate strong adsorption of selected drugs with self-assembled nanotube without altering the electronic properties. Recovery time of the complexes is also calculated to understand the regeneration of the nanotube. Results also demonstrate that van der Waals forces are major contributor in the adsorption of drug molecules within the nanotube. Our results indicate that belt[12]pyridine (2-(12BPy)) nanotube can be used as an adsorbent for the removal of toxic drug molecules from the environment. This research will benefit the scientists working in the field of new sensors for biological components and materials.

Nitrogen-doped polycrystalline diamond (N-PCD) is one of the most important carbon-based electronic materials. Here we present a systmatic investigation of the effect of high-temperature annealing (HTA) on basic physical properties of N-PCD wafer grown by microwave plasma-enhanced chemical vapor deposition (MPECVD). The metallographic and optical microscopes, X-ray diffraction,Raman spectroscopy and X-ray photoelectron spectroscopy are applied for the characterization of N-PCD before and after HTA. Particularly, we study the optoelectrnic properties of N-PCD before and after HTA by using terahertz (THz) time-domain spectroscopy. THz transmittance, dynamical and static dielectric constants and optical conductivity for N-PCD are measured. For N-PCD before HTA, we can observe a THz absorption peak induced by weak H-bonds in N-PCD, which was predicted theoretically in 1999. For N-PCD after HTA, we find that the corresponding optical conductivity can be rightly descriped by the Drude-Lorentz formula. Thus, via fitting the experimental results with the theoretical formula, we can determine optically the key electronic parameters of N-PCD after HTA, such as the electron density, the electronic relaxation time and the Lorentz frequency. The temperature dependence of these parameters is examined in the range of 80–300 K. This work demondtrates that HTA is a practical and efficient way in improving the electronic and optoelectronic properties of N-PCD. The results obtained from this research can benefit an in-depth understanding of the effect of HTA on physical properties of N-PCD from a viewpoint of semiconductor physics.

In recent years, the use of antibiotics has greatly increased, which has caused environmental pollution. We offer a photocatalyst based on BiVO₄/sulfur-doped g-C₃N₄ nanocomposite, which was made by a one-step thermal condensation method from thiourea and bismuth vanadate to degradate ciprofloxacin (CIP). The BiVO₄/sulfur-doped g-C₃N₄ photocatalyst was analyzed by certain techniques including XRD, FTIR, BET, FESEM, EDX, TEM, DRS, photoluminesence, and Mott-Schottky to determine various physicochemical properties. The photocatalytic degradation of CIP, as a model pollutant, under visible LED light irradiation was tested to investigate the catalytic performance of nanocomposite. Response Surface Methodology (RSM) was employed to optimize operational parameters, including photocatalyst dosage (50–150 mg), CIP concentration (10–30 mg/L), initial pH of the solution (3–11), and irradiation time (12–120 min). The BiVO₄/sulfur-doped g-C₃N₄ nanocomposite, with a narrow bandgap of 2.15 eV, exhibited exceptional photocatalytic performance in degrading CIP. The optimal conditions for CIP removal were photocatalyst dosage of 120.9 mg, CIP concentration of 10 mg/L, and initial solution pH of 3, resulting in 93.5 % removal efficiency after 105 min of irradiation. The photocatalytic degradation kinetics of CIP followed a pseudo-first-order model with a rate constant (K) of −0.0221 L/min, indicating rapid degradation process. The photocatalyst maintained excellent performance after 5 reuses, with only a 3 % reduction in efficiency. XRD analysis confirmed the structural stability of the nanocomposite after reuse.

Despite their significant functions and properties, the performance characteristics of Al₂O₃ ceramic particles and graphene oxide (GO) within hybrid copper composite coatings have been seldom investigated. This study successfully fabricated a Cu-GO- Al₂O₃ composite coating featuring fine particulate spherical network-like structures on St37 low carbon steel using an ultrasonic-electroless coating method. The effects of Al₂O₃-decorated graphene oxide hybrid reinforcement on the texture and nanomechanical properties of the copper matrix were examined. The tribological performance of the Cu-GO- Al₂O₃ composite coating under dry sliding conditions was evaluated, and the wear mechanism was investigated in detail. Results demonstrate that the Cu-GO- Al₂O₃ composite coating effectively reduces the wear rate and friction of the GO/ Al₂O₃ hybrid reinforced composite coating. Potentiodynamic polarization tests indicated that the Cu-GO- Al₂O₃ composite coating exhibits higher corrosion resistance compared to the copper matrix. The enhanced mechanical, tribological, and corrosion properties of the Cu-GO- Al₂O₃ composite coating are primarily attributed to: (i) the fine particulate spherical network-like structure; (ii) the synergistic effect of the GO and ceramic particle hybrid with a decorated structure; (iii) the formation of graphene oxide/ Al₂O₃ nanorolls in tribofilms and the excellent self-lubrication properties of graphene oxide. The Cu-GO- Al₂O₃ composite coating significantly improves the frictional and electrochemical properties of the copper matrix, offering new perspectives for next-generation electrical contacts and nanoelectromechanical systems.

Constructing hydrogen bonds through the heterojunction is expected be a successful tactic for achieving efficient charge separation. Here, we presented a heterojunction between 1,3,6,8-Tetra(4-carboxyphenyl) pyrene (T) and carbon nitride (CN), named T/CN. Hydrogen bonds formed between carboxyl groups of T and pyridine N in CN through the heterojunction. T/CN exhibited improved visible light absorption and enhanced charge carrier separation. The yield of CH₄ over T/CN reached up to 17.8 μmol·g⁻¹·h⁻¹, ∼7 times higher than that of CN (2.55 μmol·g⁻¹·h⁻¹). This work improved the photocatalytic performance of carbon nitride by synthesizing heterojunction catalysts containing hydrogen bonds, which provided a scheme for the diversified development of heterojunction catalysts.

Numerous energy storage parts can benefit from valuable and unique properties of MXenes. MXenes serve a variety of purposes in batteries and supercapacitors, including substrates for electrodeposition, steric hindrance, ion redistribution, bilayer and oxidation/reduction ion storage, ion transfer regulation, and more. They have been used to improve the performance and stability of separators, electrolytes and electrodes. Here, we discuss about various MXene preparation methods, its numerous physicochemical properties, and then present some recent studies in which MXene-based materials have been used as electrolytes, separators, current collectors, and binders in energy storage devices. Finally, we provide an outlook on the prospects and challenges associated with energy storage device components based on MXene and probable direction for future applications.