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•A perovskite structure LSGM material was served as membrane support.•The Al2O3 coating on the porous support can improve the wettability.•The Al2O3 modified LSGM-based membrane ...achieves a high CO2 permeation flux.
A perovskite structure La0.8Sr0.2Ga0.8Mg0.2O3−δ (LSGM), is a promising support material for dual − phase membrane for high − temperature CO2 separation owing to its high oxygen ion conductivity. The microstructure plays an important role in CO2 separation performance of the membrane. The result shows that effective particle − to − particle contact is a crucial guarantee for improving CO2 permeability. The uniformly distributed small pores of the support can greatly reduce the leakage. The Al2O3 coating on the porous support can improve the wettability between LSGM and molten carbonate, simultaneously increasing CO2 permeation flux while reducing leakage. The Al2O3 coated LSGM − based dual − phase membrane achieves a CO2 permeation flux of 0.34 mL min−1 cm−2 at 750 °C, with no detectable leakage. Above 750 °C, a reaction occurs between LSGM and molten carbonate, leading to a decline in membrane performance. For LSGM − carbonate dual − phase membranes, it is recommended to operate at temperatures not exceeding 750 °C.
Triboelectric nanogenerators (TENGs), a nascent field in energy conversion technologies, provide a novel approach to producing electrical energy from mechanical motion in the surrounding ...environment.Polymers play a key role in the functioning of TENGs through their exceptional triboelectric properties, with most triboelectric active materials being polymeric with negative affinity potential. Since there are many scientific issues that are not well understood yet regarding the working mechanism and fundamental issues regarding the role of polymers in TENGs, this review covers TENG fundamentals and effects of environmental parameters and provides a deep analytical analysis of important literature studies of TENGs. Although TENGs generate high voltage, their current generation is usually in the microamp range. Modifying polymer dielectric materials has been much investigated to enhance the output performance of TENGs. This article provides a comprehensive review of various polymer modification categories and associated performance enhancement with an analysis and comparison of research results to help grasp the big picture on the role of polymer modification on TENG performance. Specifically, the source of triboelectrification and updated knowledge about their working principle, and the quantified comparison of triboelectric material are discussed. Then physical nano and microstructure and the effect of TENG material shape on the output are brought into the discussion. Equally, the important role of chemical modification of triboelectric active polymer by way of categorization of methods and their effect on electricity generation is put under focus. In order to enhance the triboelectric negativity of polymer properties, it is useful to introduce chemical groups with high negativity, such as halogens. This can be achieved through several methods, including using a sulfur backbone or casting fluorinated self-assembly monolayers (SAMs), and the impact on TENGs' performance is explored. Furthermore, the addition of fillers to polymers is a proven technique for increasing their dielectric constant, which is emphasized as particularly significant.
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Manganese based oxides have significant potential as cathode materials for potassium ion batteries (PIB). Unfortunately, the practical application of manganese-based oxides is hindered by severe ...electrode surface erosion from electrolyte decomposition products and material expansion and collapse during potassium ion intercalation. Consequently, the surface modification strategy is adopted herein to uniformly cover the surface of K0.27MnO2·0.54 H2O (KMO) microspheres with LiF/LixPFyOz coating to effectively protect the electrode surface and significantly inhibit the collapse of the material crystal structure. Additionally, the coating exhibits excellent electron/ion conductivity, enhancing the diffusion efficiency of potassium ions within the electrode material. The existence of LiF/LixPFyOz coating is confirmed by characterization measurements. The LiF/LixPFyOz-coated KMO microspheres (sample LLO@KMO-2) exhibit outstanding cyclic stability (66.3 % capacity retention at 50 mA g−1) and high discharge capacity (100.2 mAh g−1 at 50 mA g−1), demonstrating their excellent cycle stability. The modification strategy of LiPF6-electrolyte-solvothermal coating provides an innovative surface modification method for potassium ion batteries, showcasing its potential for application in future high-performance battery technologies.
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•The LiF/LixPFyOz coated KMO is synthesized by electrolyte solvothermal coating process.•The LLO@KMO samples improve the velocity of K+ migration on electrode surface.•The LiF/LixPFyOz layer suppresses the surface side reaction of materials from the electrolyte.
Carbon fibers were surface modified with acrylate-derived polymers with aromatic side chains, to protect the fiber when exposed to high temperatures.The surface modification process induced a ...significant increase in tensile strength (23.7%) and tensile modulus (8%), for the benzyl-bearing side chain andretained superior tensile strength (20%) and tensile modulus (7%)after heating to 600 °C. Commercialcarbon fibres gave asignificant decrease in tensile strength and modulus, 7% and 4%, respectively, when exposed to the same conditions. This suggests that the surface modification process provides a protective effect against thermal degradation, with possible application in carbon fibre recycling.The interfacial shear strength (IFSS) showed significant improvementbefore (up to 208%) and after (up to 84%) exposure to high temperatures. Analysis of the carbon fiber surface byXPS suggests that the surface bound polymer becomes more graphitic, potentiallyviathe fusion of the aromatic side chains.
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•Novel alkali intercalated & acid exfoliated biochars were made from walnut shells.•Biochars showed a maximum increase of 400% to 500% in surface and microporous areas.•Alkali salts ...formed during the modification were the reason for enhanced properties.•Malachite green dye adsorption capacity of the biochars increased by 250%•Rate of adsorption for malachite green dye increased by 1000% for modified biochars.
Cost-effective and eco-friendly adsorbents are essential in environmental engineering and biochar is a promising material from the perspective. A novel and efficient surface modification approach involving alkali intercalation and acid exfoliation was designed in this study to enhance the physicochemical properties of biochar. The alkali intercalation process utilizes potassium hydroxide (KOH), while acid exfoliation involves varying HNO3, H2SO4, and H3PO4 concentrations. A simple two-stage pyrolysis process was employed to facilitate the intercalation-exfoliation modification. The modified biochars were characterized using BET, SEM, XRD, etc., to understand physicochemical properties. To quantify the effectiveness of the modifications, adsorption of malachite green dye as a model moiety was investigated. Dye removal sorption rates exceeding 99 % were recorded in the case of the biochars modified through a two-step process using KOH and 0.1MH3PO4. Specifically, the highest contaminant removal of 99.9 % was recorded when 60 mg of the KOH-0.1MH3PO4 biochar was employed, which is significantly higher than unmodified biochar’s 45.41 % removal at a higher dosage of 100 mg. Moreover, the adsorption kinetics revealed that all the modified biochars attained the maximum removal concentrations (∼99 % removal) in a mere 300 min, indicating a tenfold improvement in adsorption rate from unmodified biochar's requirement of over 5000 min. The results achieved through this study provide a cost-effective, fast, and environment-friendly technology for enhancing the adsorption characteristics and performance of biochars toward contaminant removal.
Energy and water are the two major issues facing the modern mankind. Providing freshwater requires energy and producing energy uses water. In the present-day scenario, both these routes face growing ...problems and limitations. Energy crisis has risen due to the depletion of fossil fuels that cause pollution to water bodies making the water unusable for human consumption. In this regard, semiconductor nanocrystals with luminescent properties or carbon quantum dots (CQDs) are the newly developed nanomaterials whose distinctive photo-physical characteristics are focusing to a new generation of robust materials and sensors for sustainable development. In this review, advances in surface and band gap modification of CQDs to improve the activity of nanomaterials will be discussed with special reference to some specific CQDs exhibiting special optical properties for water treatment/splitting applications. Recent advances on CQDs nanocomposites including their applications in photodegradation of organic pollutants, sensing of heavy metal ions in water and water splitting are discussed critically to narrate the future prospects in this field. Challenges and limitations for further improvement are covered to provide smart choices for creating sustainability of benign environment and economic benefits.
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•The review covers the recent work based on carbon quantum dots photocatalysts for sustainable development.•Effect of band gap tuning and surface modification of CQDs is extensively discussed.•Photocatalytic applications of CQDs based hybrids for water treatment and hydrogen production are discussed.•The review also highlights some challenges and limitations for improved catalytic activity of CQDs.
The Ti-6Al-7 Nb alloy and its carbide possess a wide range of engineering applications, therefore, it is utmost required to fabricate high-quality carburized layers on the alloy surface. In this ...study, the carburization of Ti-6Al-7 Nb alloy was conducted using molten salts (including Carbon Nano Tubes, LiCl, KCl, and KF) in a planetary ball mill, followed by placement in an alumina tube furnace under a nitrogen atmosphere at 1050 °C for various durations. Several characterization techniques were employed to analyze the results, including X-ray diffraction (XRD), field emission electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The XRD results reveal that as the carburization duration increased, the alloy achieved complete carburization, forming a 120 µm thick layer of TiC0.3N0.7. After 24 h of carburization, the crystallite size of TiC0.3N0.7 increased, and the micro-strain decreased, indicating improved structural quality. The morphology of the carburized layer at shorter durations exhibits micro-cracks and defects due to incomplete carburization, where carbon (C) and nitrogen (N) could not effectively occupy in the grain boundaries of alloy. After 24 h, an agglomerated, cauliflower-like layer of TiC0.3N0.7 formed, enhancing the alloy's engineering properties. XPS confirmed the presence of carbon and nitrogen in the carburized sample, which contributed to the formation of the TiC0.3N0.7 layer on the alloy surface. AFM analysis supported the SEM findings, revealing broad islands with microgrooves on the carburized layer. These features indicate a thick and well-formed carburized layer, confirming the successful carburization of Ti-6Al-7 Nb. Overall, the study demonstrates that a 24-h carburization process at 1050 °C in molten salts under a nitrogen atmosphere effectively produces a high-quality, thick, and adherent TiC0.3N0.7 layer on Ti-6Al-7 Nb alloy, significantly enhancing its engineering properties.
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•Carburization of Ti-6Al-7 Nb was successfully achieved after 24 h at 1050 °C.•Low duration of carburization leads to form cracks in the carburized layer.•C and N diffuse into grain boundary during carburization and form TiC0.3N0.7 layer.•TiC0.3N0.7 form a homogenous carburized layer after 12 and 24 h of carburization.
A multimode sensing and imaging platform based on surface modification strategy of Ru(bpy)32+ doped SiO2 nanoparticles (RuSiO2 NPs) was constructed for versatile detection of glutathione (GSH). ...RuSiO2 NPs as the luminophore models had outstanding fluorescence (FL) and electrochemiluminescence (ECL) signals. Furthermore, its FL signal could be captured by electrophoresis analyzer, and the ECL signal could be imaged with mobile phone to achieve visualization. So, a unique and convenient multi-mode sensing and imaging platform could be developed based on RuSiO2 NPs. SiO2 NPs could realize enrichment of Ru(bpy)32+ based on the nanoconfined effect to achieve signal amplification, and its surface was rich with abundant hydroxyl functional groups, which offered a channel for surface modification. Sulfhydryl modification on the RuSiO2 NPs was realized by using silane coupling agent, and KMnO4 was used to in situ generate MnO2 shell on the surface of RuSiO2 NPs for quenching its ECL, FL, and colorimetric (CL) signals based on resonance energy transfer (RET). Target GSH could reduce MnO2 shell to realize recovery of all signals, thus achieving the label-free multimode detection of GSH. Therefore, this work developed a multimode sensing and imaging platform without signal labels or layer-by-layer assembly of electrodes, which had the advantages of simple steps, low cost, and high detection accuracy, showing important application potential in the field of bioanalysis.
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•This work developed a multimode sensing and imaging platform based on surface modification strategy.•This work did not require layer-by-layer assembly of electrodes, which greatly reduced detection costs and time.•RuSiO2 NPs not only displayed outstanding FL and ECL signals, but also had the potential for imaging applications.•The CL imaging of FL and ECL signals from RuSiO2 was performed by electrophoresis analyzer and mobile phone, respectively.
•Laser treatment can modulate the morphology, thickness and density of HA coating.•Microstructures and thin oxide layers promote nucleation and deposition of HA.•Adhesion strength of HA coating to Mg ...alloy substrate is 31.86 ± 1.71 MPa.•Coating effectively reduces the corrosion rate of magnesium alloys to 0.146 mm/y.•Coating with good biological activity can promotes osteoblasts proliferation.
Magnesium and its alloys have attracted attention as medical bone implant materials due to their excellent biocompatibility, bone-like mechanical properties, and degradability. However, the clinical application of magnesium is limited by the fact that it corrodes too quickly in body fluids, leading to premature mechanical failure. Surface hydroxyapatite coatings can significantly reduce the initial corrosion of magnesium alloys, but suffer from the problems of non-dense coatings, many defects and poor adhesion strength to the substrate. In this study, we propose femtosecond laser construction of microemulsion cone structures on the surface of magnesium alloys to significantly enhance the densities and thicknesses of the coatings, as well as to improve the bonding strength of the coatings to the substrate, which ultimately reduces the corrosion rate. The corrosion rate of modified hydroxyapatite coating in simulated body fluid is only 0.146 mm/y, and it has the ability to rapidly induce hydroxyapatite mineralization and promote osteoblast proliferation. Furthermore, the surface morphology, chemical composition, and wettability of the laser-modified Mg alloy were analyzed. It was demonstrated that the microstructure and thin oxide layer formed on the surface of the magnesium alloy could provide more sites for HA nucleation, which promotes the deposition and growth of HA and the existence of a mechanical interlocking effect with the substrate. The application of femtosecond laser surface modification represents a rapid and efficacious approach to enhance the quality of hydroxyapatite coatings. This method has successfully controlled the corrosion rate of magnesium alloys with excellent biocompatibility, thereby overcoming potential obstacles to the use of magnesium alloys in clinical applications.
