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•Electrochemical exfoliation of graphite in molten NaCl was examined.•The role of hydrogen in the exfoliation process is highlighted.•The exfoliation led to the production of 3D ...graphene nanosheets.•The graphene nanosheets exhibited a high electrical conductivity.•The process can be scaled up for large scale production.
The electrochemical exfoliation of graphite in molten NaCl under an Ar-4%H2 atmosphere was examined, and found to be a possible economic method for the green production of highly crystalline 3D graphene related nanostructures in a large scale. The role of hydrogen in the exfoliation process is highlighted. The graphene product exhibited a uniform mesoporous structure, high electrical conductivity of 2.1×105Sm−1 as well as a specific surface area of 232m2g−1 and thermal stability in air at temperatures below 500°C. The exfoliation rate was estimated to be about 200g graphene per liter of molten NaCl per day.
This study investigates the improvement in the compressive strength of cellulose/cement-based composites. Methyl cellulose (MC), carboxymethyl cellulose (CMC), and hydroxypropyl cellulose (HPMC) are ...separately used as the cellulose phase with different wt%. Graphene oxide (GO) and zoledronic acid (ZOL) are used as additives for bone regeneration for various formulations. Utilizing Extreme Gradient Boosting (XGB) modeling, this research demonstrates the roles of the choice of the cellulose phase, wt% of cement phase, % gelatin, % citric acid, degradation time, and concentration of GO and ZOL in influencing compressive strength. The XGB regression model, with an R
value of 0.99 (~1), shows the predictive power of the model. Feature importance analysis demonstrates the significance of cellulose choice and the addition of chitosan in enhancing compressive strength. The correlation heatmap reveals positive associations, emphasizing the positive influence of HPMC and CMC compared with MC and the substantial impact of chitosan and citric acid on compressive strength. The model's predictive accuracy is validated through predicted compressive strength values with experimental observations, providing insights for optimizing cellulose-reinforced cements and enabling tailored material design for enhanced mechanical performance.
In the current study, the mineralization of AO7 has been studied by a novel electrochemical advanced oxidation process (EAOP) consisting of the electro-Fenton (EF) oxidation using chalcopyrite as the ...heterogeneous catalyst. In this process, chalcopyrite (CP) powder was employed as the source of Fe2+ and Cu2+ co-catalysts, instead of a soluble iron salt which is used in classic EF. This new process, called here as CP-EF, was able to remove 95% TOC of AO7 under an optimum experimental condition, while the removal of only 80% TOC was observed at the optimal classic EF treatments. On the other hand, a comparative study was carried out between the CP-EF and CP-PEF processes showed the superiority of heterogeneous PEF for decolorization AO7. To test the stability and reusability of our chalcopyrite based heterogeneous catalyst, leaching and cyclic experiments were carried out, based on which the catalyst was found to be reusable with a reduction of 95% in TOC removal after 6 h of electrolysis. Although both processes were effective for the treatment of AO7, the possibility of reusing the catalyst in the heterogeneous EF process justifies its economic viability in comparison with the classic electro-Fenton process. Ion chromatography analysis confirmed the release of NO3− and NH4+ ions during the AO7 mineralization.
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•Degradation of AO7 by electro-Fenton (EF) process using chalcopyrite (CP) as heterogeneous catalyst at natural pH.•Almost total mineralization (95%) of 0.52 mM AO7 aqueous solution after 6 h.•CP-PEF is more efficient than CP-EF and Classic-EF.•Similar efficiency of recycled CP after 5 cycle of reuse.
The structural and microstructural changes in graphite occurring by heating a mixture of synthetic polycrystalline graphite and lithium chloride to 1250°C are studied by thermal analysis, X-ray ...diffraction, Raman scattering and microscopy. The average crystallite size of the graphite was found to increase significantly after the heat treatment. Although the oxidation of graphite was largely inhibited, different forms of corrosion attack on the graphite were observed. Consequently, these led to the formation of different microstructures comprising exfoliated carbon sheets and nanosheets, pitted particles and carbon nanorods. The possible mechanisms related to the microstructural changes are discussed. The effect of heating rate on the oxidation in air of graphite powder is also investigated.
This study examines the preparation of graphitic carbon nanostructures, including carbon nanotubes (CNTs) with both cylindrical and bamboo-like morphology and spherical carbon nanoparticles by ...electrochemical erosion of graphite cathodes in molten LiCl on a scale of more than 10g which could easily be increased to a larger scale. A uniform erosion of graphite electrodes was achieved using bare electrodes immersed in molten salt. It was demonstrated that any shadow on the graphite cathode made by ceramic insulators impedes erosion of the electrode. Moreover, the carbon products obtained at different cathode current densities ranging from about 0.4 to 1Acm−2 were characterized by electron microscopy. Accordingly, a mechanism is proposed for the erosion of the graphite electrodes, based on the electrochemical peeling and etching of graphite flakes in negative electrodes, leading to the formation of CNTs and spherical nanoparticles, respectively.
We report on the facile and scalable catalytic conversion of natural graphite and MoS2 minerals into α-MoO3 nanoribbons incorporated into hexagonal MoS2 and graphene nanosheets, and evaluate the ...structural, morphological and electrochemical performances of the hybrid nanostructured material obtained. Mechanochemical treatment of raw materials, followed by catalytic molten salt treatment leads to the formation of nanostructures with promising electrochemical performances. We examined the effect of processing temperature on the electrochemical performance of the products. At 1100 °C, an excellent Li-ion storage capacity of 773.5 mAh g−1 is obtained after 180 cycles, considerably greater than that of MoS2 (176.8 mAh g−1). The enhanced capacity and the rate performance of this electrode are attributed to the well-integrated components, characterized by the formation of interfacial molybdenum oxycarbide layer during the synthesis process, contributing to the reduced electrical/electrochemical resistance of the sample. This unique morphology promotes the charge and ions transfer through the reduction of the Li-ion diffusion coefficient (1.2 × 10−18 cm2 s−1), enhancing the pseudocapacitive performance of the electrode; 59.3% at the scan rate of 0.5 mV s−1. This article provides a green and low-cost route to convert highly available natural graphite and MoS2 minerals into nanostructured hybrid materials with promising Li-ion storage performance.
Silicon Fen (SF) is a cluster of high-tech firms located around the University of Cambridge (UoC) in the UK. This article, for the first time, investigates the technological bonds between SF firms ...and UoC based on patent analysis covering the period of 1999-2021. We provide a short history of SF, highlighting its early formation and growth, and the role of spin-off firms on its evolution. We employ joint patents generated by UoC and various business sectors of SF to calculate the values of technological collaboration strength (TCS). It is found that the majority of joint patents (61%) are generated by the Pharma/Biotech sector of SF with the highest value of TCS (16.45 × 10−3). Moreover, the patent's economic values across various business disciplines in SF are calculated based on the total counts of citations. Our observations suggest that senior university academics making spin-off firms in a business cluster around their university can effectively facilitate university-firm technological collaboration. Furthermore, the relatively strong technological bond between UoC and the Pharma/Biotech sector of SF is confirmed to be influenced by the collaboration of the university with its own spin-off firms rather than large independent firms in SF. The outcomes of this research contribute to the knowledge of the collaboration between a main research university and a cluster of firms located in its geographical proximity.
Hard carbon materials are considered to be the most practical anode materials for sodium ion batteries because of the rich availability of their resources and potentially low cost. Here, the ...conversion of corn leaf biomass, a largely available agricultural waste, into carbonaceous materials for Na-ion storage application is reported. Thermal analysis investigation determines the presence of exothermic events occurring during the thermal treatment of the biomass. Accordingly, various temperatures of 400, 500, and 600 °C are selected to perform carbonization treatment trials, leading to the formation of various biocarbons. The materials obtained are characterized by a combination of methods, including X-ray diffraction, electron microscopy, surface evaluation, Raman spectroscopy, and electrochemical characterizations. The Na-ion storage performances of these materials are investigated using water-soluble carboxymethyl cellulose binder, highlighting the influence of the carbonization temperature on the electrochemical performance of biocarbons. Moreover, the influence of post-mechanochemical treatment on the Na-ion storage performance of biocarbons is studied through kinetic evaluations. It is confirmed that reducing the particle sizes and increasing the carbon purity of biocarbons and the formation of gel polymeric networks would improve the Na-ion storage capacity, as well as the pseudocapacitive contribution to the total current. At a high-current density of 500 mA g−1, a specific Na-ion storage capacity of 134 mAh g−1 is recorded on the biocarbon prepared at 600 °C, followed by ball-milling and washing treatment, exhibiting a reduced charge transfer resistance of 49 Ω and an improved Na-ion diffusion coefficient of 4.8 × 10−19 cm2 s−1. This article proposes a simple and effective technique for the preparation of low-cost biocarbons to be used as the anode of Na-ion batteries.
•Review and critical analysis of the orthogonal polynomial methods for modeling elastodynamic wave propagation in composites.•Emphasis on the mathematical links between the conventional and improved ...versions of polynomial methods.•Critical numerical comparison between the exact solution and polynomial expansion solution.
The growing usage of elastic, piezoelectric and magneto-electro-elastic composites has motivated the scientific and industrial communities to develop new numerical methods, which can provide alternative ways of predicting the dynamic responses. Such numerical methods are considered as important tools for the modeling and design of the reliable structural health monitoring. Among them, orthogonal polynomial expansions are best suited to predicting acoustic wave dispersion curves in composites. Despite their simplicity and computational efficiency, polynomial methods can only provide satisfactory outcomes with multilayered structures in which the properties of successive layers do not change significantly. As such, a sufficiently great deal of dissimilarity across the constituent plates give rise to significant field level discontinuities at interfaces, which affect their effectiveness. By considering this critical point, the review of the research progress in the field is of importance, in order to understand the relationship between the composites type and the effectiveness of polynomial methods. This review article deals with this issue in detail. Moreover, a numerical comparison is made between the conventional and improved version of this method, where the outcome is critically discussed. This review article outlines the recent advances, challenges, and prospects of polynomial approaches, providing new insights for future studies.
