In the present study, polyethersulfone based nanohybrid membranes were effectively fabricated by incorporating graphene oxide(GO) and hydrotalcite(HT) nanosheets into the membrane structure. HT was prepared to overcom...In the present study, polyethersulfone based nanohybrid membranes were effectively fabricated by incorporating graphene oxide(GO) and hydrotalcite(HT) nanosheets into the membrane structure. HT was prepared to overcome the irreversible agglomeration behavior of GO at a high concentration which affects the performance of the membranes. In particular, the shedding of HT in formamide provides a two-dimensional nanosheet with a higher positive charge density to prevent the restacking of GO nanosheets. Here, exfoliated GO and HT with different combinations(1:1, 1:2 and 1:3) were infused in the membrane matrix to treat lead-acid battery effluent effectively. Finally, the hybrid membranes were characterized for hydrophilicity, mechanical strength and pure water flux. In combination with the superior properties of GO and HT, the prepared hybrid membranes can be used as effectively to improve the separation and permeation performance. The phase inversion process eliminated the leaching of nanoparticles from the membrane matrix. The reusability of the hybrid membrane was achieved using0.1 mol·L^(-1)NaOH solution and reused without significant reduction in lead removal efficiency. The cost analysis of the membrane was also estimated from the lab study. Therefore, the present study suggested the selective and sustainable treatment of lead from a real-life effluent.展开更多
Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH_(4))_(4)[NiH_(6)Mo_(6)O_(4...Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH_(4))_(4)[NiH_(6)Mo_(6)O_(4)]·5H_(2)O polyoxometalates(NiMo_(6))are adopted as the cluster precursors for simple fabrication of heterostructured Pt-Ni_(3)Mo_(3)N nanohybrids supported by carbon black(Pt-Ni_(3)Mo_(3)N/C)without using additional N sources.The improved porosity and enhanced electronic interaction of Pt-Ni_(3)Mo_(3)N/C should be attributed to the integration of Pt with NiMo_(6),which favors the mass transport,promotes the formation of exposed catalytic sites,and benefits the regulation of intrinsic activity.Thus,the as-obtained Pt-Ni_(3)Mo_(3)N/C exhibits impressive and durable HER performance as indicated by the low overpotential of 13.7 mV at the current density of 10 mA cm^(-2) and the stable overpotential during continuous working at 100 mA cm^(-2) for 100 h.This work provides significant insights for the synthesis of new highly active heterostructured electrocatalysts for renewable energy devices.展开更多
Magnesium(Mg)alloys are gaining great consideration as body implant materials due to their high biodegradability and biocompatibility.However,they suffer from low corrosion resistance and antibacterial activity.In thi...Magnesium(Mg)alloys are gaining great consideration as body implant materials due to their high biodegradability and biocompatibility.However,they suffer from low corrosion resistance and antibacterial activity.In this research,semi-powder metallurgy followed by hot extrusion was utilized to produce the magnesium oxide@graphene nanosheets/magnesium(MgO@GNS/Mg)composite to improve mechanical,corrosion and cytocompatibility characteristics.Investigations have revealed that the incorporation of MgO@GNS nanohybrids into Mg-based composite enhanced microhardness and compressive strength.In vitro,osteoblast cell culture tests show that using MgO@GNS nanohybrid fillers enhances osteoblast adhesion and apatite mineralization.The presence of MgO@GNS nanoparticles in the composites decreased the opening defects,micro-cracks and micro-pores of the composites thus preventing the penetration of the corrosive solution into the matrix.Studies demonstrated that the MgO@GNS/Mg composite possesses excellent antibacterial properties because of the combination of the release of MgO and physical damage to bacterium membranes caused by the sharp edges of graphene nanosheets that can effectively damage the cell wall thereby facilitating penetration into the bacterial lipid bilayer.Therefore,the MgO@GNS/Mg composite with high mechanical strength,antibacterial activity and corrosion resistance is considered to be a promising material for load-bearing implant applications.展开更多
This work uses refined first-order shear theory to analyze the free vibration and transient responses of double-curved sandwich two-layer shells made of auxetic honeycomb core and laminated three-phase polymer/GNP/fib...This work uses refined first-order shear theory to analyze the free vibration and transient responses of double-curved sandwich two-layer shells made of auxetic honeycomb core and laminated three-phase polymer/GNP/fiber surface subjected to the blast load.Each of the two layers that make up the double-curved shell structure is made up of an auxetic honeycomb core and two laminated sheets of three-phase polymer/GNP/fiber.The exterior is supported by a Kerr elastic foundation with three characteristics.The key innovation of the proposed theory is that the transverse shear stresses are zero at two free surfaces of each layer.In contrast to previous first-order shear deformation theories,no shear correction factor is required.Navier's exact solution was used to treat the double-curved shell problem with a single title boundary,while the finite element technique and an eight-node quadrilateral were used to address the other boundary requirements.To ensure the accuracy of these results,a thorough comparison technique is employed in conjunction with credible statements.The problem model's edge cases allow for this kind of analysis.The study's findings may be used in the post-construction evaluation of military and civil works structures for their ability to sustain explosive loads.In addition,this is also an important basis for the calculation and design of shell structures made of smart materials when subjected to shock waves or explosive loads.展开更多
The exceptional properties of graphene make it ideal as a reinforcement to enhance the properties of aluminum matrices and this critically depends on uniform dispersion. In this study, the dispersion issue was address...The exceptional properties of graphene make it ideal as a reinforcement to enhance the properties of aluminum matrices and this critically depends on uniform dispersion. In this study, the dispersion issue was addressed by sonication and non-covalent surface functionalization of graphite nanoplatelets（GNPs） using two types of surfactant： anionic（sodium dodecyl benzene sulfate（SDBS）） and non-ionic polymeric（ethyl cellulose（EC））. After colloidal mixing with Al powder, consolidation was performed at two sintering temperatures（550 and 620°C）. The structure, density, mechanical and wear properties of the nanocomposite samples were investigated and compared with a pure Al and a pure GNPs/Al nanocomposite sample. Noticeably, EC-based 0.5 wt% GNPs/Al samples showed the highest increment of 31% increase in hardness with reduced wear rate of 98.25% at 620°C, while a 22% increase in hardness with reduced wear rate of 96.98% at 550°C was observed, as compared to pure Al. Microstructural analysis and the overall results validate the use of EC-based GNPs/Al nanocomposites as they performed better than pure Al and pure GNPs/Al nanocomposite at both sintering temperatures.展开更多
Multiwall carbon nanotubes （MWNTs） and alumina are combined to give a new type of nanohybrid for Fisher-Tropsch synthesis （FTS） catalyst support. Alumina nano-particles （10 wt%） were introduced directly on funct...Multiwall carbon nanotubes （MWNTs） and alumina are combined to give a new type of nanohybrid for Fisher-Tropsch synthesis （FTS） catalyst support. Alumina nano-particles （10 wt%） were introduced directly on functionalized MWNTs by a modified sol-gel method. Microstructure observations show that alumina particles were homogeneously dispersed on the inside and outside of modified MWNTs surfaces. 15 wt% cobalt loading catalysts were prepared with this nanohybrid and γ-alumina as a reference, using a sol-gel technique and wet impregnation method respectively. These catalysts were characterized by TEM, XRD, N2-adsorption, H2 chemisorption and TPR. The deposition of cobalt nanoparticles synthesized by sol-gel technique on the MWNTs nanohybrid shift the reduction peaks to a low temperature, indicating higher reducibility for uniform cobalt particles. Nanohybrid also aided in high dispersion of metal clusters and high stability and performance of catalyst. The proposed MWNTs nanohybrid-supported cobalt catalysts showed the improved FTS rate （gHc/（gcat.min））, CO conversion （%）, and water gas shift rate （WGS）（gcoz/（gcat.h）） of 0.012, 52, and 30E-3, respectively, as compared to those of 0.007, 25, and 18E-3, respectively, on the γ-alumina-supported cobalt catalysts with the same Co loading.展开更多
Hybrid materials are attracting intensive attention for their applications in electronics, photoelectronics, LEDs, field-effect transistors, etc. Engineering new hybrid materials and further exploiting their new funct...Hybrid materials are attracting intensive attention for their applications in electronics, photoelectronics, LEDs, field-effect transistors, etc. Engineering new hybrid materials and further exploiting their new functions will be significant for future science and technique development. In this work, alternatively stacked self-assembled CoAl LDH/MoS2 nanohybrid has been successfully synthesized by an exfoliation-flocculation method from positively charged CoAl LDH nanosheets（CoAl-NS） with negatively charged MoS2 nanosheets（MoS2-NS）. The CoAl LDH/MoS2 hybrid material exhibits an enhanced catalytic performance for oxygen evolution reaction（OER） compared with original constituents of CoAl LDH nanosheets and MoS2 nanosheets. The enhanced OER catalytic performance of CoAl LDH/MoS2 is demonstrated to be due to the improved electron transfer, more exposed catalytic active sites, and accelerated oxygen evolution reaction kinetics.展开更多
文摘In the present study, polyethersulfone based nanohybrid membranes were effectively fabricated by incorporating graphene oxide(GO) and hydrotalcite(HT) nanosheets into the membrane structure. HT was prepared to overcome the irreversible agglomeration behavior of GO at a high concentration which affects the performance of the membranes. In particular, the shedding of HT in formamide provides a two-dimensional nanosheet with a higher positive charge density to prevent the restacking of GO nanosheets. Here, exfoliated GO and HT with different combinations(1:1, 1:2 and 1:3) were infused in the membrane matrix to treat lead-acid battery effluent effectively. Finally, the hybrid membranes were characterized for hydrophilicity, mechanical strength and pure water flux. In combination with the superior properties of GO and HT, the prepared hybrid membranes can be used as effectively to improve the separation and permeation performance. The phase inversion process eliminated the leaching of nanoparticles from the membrane matrix. The reusability of the hybrid membrane was achieved using0.1 mol·L^(-1)NaOH solution and reused without significant reduction in lead removal efficiency. The cost analysis of the membrane was also estimated from the lab study. Therefore, the present study suggested the selective and sustainable treatment of lead from a real-life effluent.
基金the financial support from the Key Research and Development Program sponsored by the Ministry of Science and Technology(MOST)(2022YFB4002000,2022YFA1203400)the National Natural Science Foundation of China(22102172,22072145,22372155,22005294,21925205,21721003)。
文摘Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH_(4))_(4)[NiH_(6)Mo_(6)O_(4)]·5H_(2)O polyoxometalates(NiMo_(6))are adopted as the cluster precursors for simple fabrication of heterostructured Pt-Ni_(3)Mo_(3)N nanohybrids supported by carbon black(Pt-Ni_(3)Mo_(3)N/C)without using additional N sources.The improved porosity and enhanced electronic interaction of Pt-Ni_(3)Mo_(3)N/C should be attributed to the integration of Pt with NiMo_(6),which favors the mass transport,promotes the formation of exposed catalytic sites,and benefits the regulation of intrinsic activity.Thus,the as-obtained Pt-Ni_(3)Mo_(3)N/C exhibits impressive and durable HER performance as indicated by the low overpotential of 13.7 mV at the current density of 10 mA cm^(-2) and the stable overpotential during continuous working at 100 mA cm^(-2) for 100 h.This work provides significant insights for the synthesis of new highly active heterostructured electrocatalysts for renewable energy devices.
文摘Magnesium(Mg)alloys are gaining great consideration as body implant materials due to their high biodegradability and biocompatibility.However,they suffer from low corrosion resistance and antibacterial activity.In this research,semi-powder metallurgy followed by hot extrusion was utilized to produce the magnesium oxide@graphene nanosheets/magnesium(MgO@GNS/Mg)composite to improve mechanical,corrosion and cytocompatibility characteristics.Investigations have revealed that the incorporation of MgO@GNS nanohybrids into Mg-based composite enhanced microhardness and compressive strength.In vitro,osteoblast cell culture tests show that using MgO@GNS nanohybrid fillers enhances osteoblast adhesion and apatite mineralization.The presence of MgO@GNS nanoparticles in the composites decreased the opening defects,micro-cracks and micro-pores of the composites thus preventing the penetration of the corrosive solution into the matrix.Studies demonstrated that the MgO@GNS/Mg composite possesses excellent antibacterial properties because of the combination of the release of MgO and physical damage to bacterium membranes caused by the sharp edges of graphene nanosheets that can effectively damage the cell wall thereby facilitating penetration into the bacterial lipid bilayer.Therefore,the MgO@GNS/Mg composite with high mechanical strength,antibacterial activity and corrosion resistance is considered to be a promising material for load-bearing implant applications.
文摘This work uses refined first-order shear theory to analyze the free vibration and transient responses of double-curved sandwich two-layer shells made of auxetic honeycomb core and laminated three-phase polymer/GNP/fiber surface subjected to the blast load.Each of the two layers that make up the double-curved shell structure is made up of an auxetic honeycomb core and two laminated sheets of three-phase polymer/GNP/fiber.The exterior is supported by a Kerr elastic foundation with three characteristics.The key innovation of the proposed theory is that the transverse shear stresses are zero at two free surfaces of each layer.In contrast to previous first-order shear deformation theories,no shear correction factor is required.Navier's exact solution was used to treat the double-curved shell problem with a single title boundary,while the finite element technique and an eight-node quadrilateral were used to address the other boundary requirements.To ensure the accuracy of these results,a thorough comparison technique is employed in conjunction with credible statements.The problem model's edge cases allow for this kind of analysis.The study's findings may be used in the post-construction evaluation of military and civil works structures for their ability to sustain explosive loads.In addition,this is also an important basis for the calculation and design of shell structures made of smart materials when subjected to shock waves or explosive loads.
文摘The exceptional properties of graphene make it ideal as a reinforcement to enhance the properties of aluminum matrices and this critically depends on uniform dispersion. In this study, the dispersion issue was addressed by sonication and non-covalent surface functionalization of graphite nanoplatelets（GNPs） using two types of surfactant： anionic（sodium dodecyl benzene sulfate（SDBS）） and non-ionic polymeric（ethyl cellulose（EC））. After colloidal mixing with Al powder, consolidation was performed at two sintering temperatures（550 and 620°C）. The structure, density, mechanical and wear properties of the nanocomposite samples were investigated and compared with a pure Al and a pure GNPs/Al nanocomposite sample. Noticeably, EC-based 0.5 wt% GNPs/Al samples showed the highest increment of 31% increase in hardness with reduced wear rate of 98.25% at 620°C, while a 22% increase in hardness with reduced wear rate of 96.98% at 550°C was observed, as compared to pure Al. Microstructural analysis and the overall results validate the use of EC-based GNPs/Al nanocomposites as they performed better than pure Al and pure GNPs/Al nanocomposite at both sintering temperatures.
基金supported by the Research Council of the Research Institute of Petroleum Industrythe Research and Development of the National Iranian Oil Company
文摘Multiwall carbon nanotubes （MWNTs） and alumina are combined to give a new type of nanohybrid for Fisher-Tropsch synthesis （FTS） catalyst support. Alumina nano-particles （10 wt%） were introduced directly on functionalized MWNTs by a modified sol-gel method. Microstructure observations show that alumina particles were homogeneously dispersed on the inside and outside of modified MWNTs surfaces. 15 wt% cobalt loading catalysts were prepared with this nanohybrid and γ-alumina as a reference, using a sol-gel technique and wet impregnation method respectively. These catalysts were characterized by TEM, XRD, N2-adsorption, H2 chemisorption and TPR. The deposition of cobalt nanoparticles synthesized by sol-gel technique on the MWNTs nanohybrid shift the reduction peaks to a low temperature, indicating higher reducibility for uniform cobalt particles. Nanohybrid also aided in high dispersion of metal clusters and high stability and performance of catalyst. The proposed MWNTs nanohybrid-supported cobalt catalysts showed the improved FTS rate （gHc/（gcat.min））, CO conversion （%）, and water gas shift rate （WGS）（gcoz/（gcat.h）） of 0.012, 52, and 30E-3, respectively, as compared to those of 0.007, 25, and 18E-3, respectively, on the γ-alumina-supported cobalt catalysts with the same Co loading.
基金financially supported by NNSFC(No.21025104,21271171,and 91022018)
文摘Hybrid materials are attracting intensive attention for their applications in electronics, photoelectronics, LEDs, field-effect transistors, etc. Engineering new hybrid materials and further exploiting their new functions will be significant for future science and technique development. In this work, alternatively stacked self-assembled CoAl LDH/MoS2 nanohybrid has been successfully synthesized by an exfoliation-flocculation method from positively charged CoAl LDH nanosheets（CoAl-NS） with negatively charged MoS2 nanosheets（MoS2-NS）. The CoAl LDH/MoS2 hybrid material exhibits an enhanced catalytic performance for oxygen evolution reaction（OER） compared with original constituents of CoAl LDH nanosheets and MoS2 nanosheets. The enhanced OER catalytic performance of CoAl LDH/MoS2 is demonstrated to be due to the improved electron transfer, more exposed catalytic active sites, and accelerated oxygen evolution reaction kinetics.
