Defect engineering can give birth to novel properties for adsorption and photocatalysis in the control of antibiotics and heavy metal combined pollution with photocatalytic composites.However,the role of defects and t...Defect engineering can give birth to novel properties for adsorption and photocatalysis in the control of antibiotics and heavy metal combined pollution with photocatalytic composites.However,the role of defects and the process mechanism are complicated and indefinable.Herein,TiO_(2)/CN/3DC was fabricated and defects were introduced into the tripartite structure with separate O_(2)plasma treatment for the single component.We find that defect engineering can improve the photocatalytic activity,attributing to the increase of the contribution from h^(+)and OH.In contrast to TiO_(2)/CN/3DC with a photocatalytic tetracycline removal rate of 75.2%,the removal rate of TC with D-TiO_(2)/CN/3DC has increased to 88.5%.Moreover,the reactive sites of tetracycline can be increased by adsorbing on the defective composites.The defect construction on TiO_(2)shows the advantages in tetracycline degradation and Cu^(2+)adsorption,but also suffers significant inhibition for the tetracycline degradation in a tetracycline/Cu^(2+)combined system.In contrast,the defect construction on graphene can achieve the cooperative removal of tetracycline and Cu^(2+).These findings can provide new insights into water treatment strategies with defect engineering.展开更多
Polyacrylic acid(PAA)hydrogel composites with different hexagonal boron nitride(h-BN)fillers were synthesized and successfully 3D-printed while their thermal conductivity was systematically studied.With the content of...Polyacrylic acid(PAA)hydrogel composites with different hexagonal boron nitride(h-BN)fillers were synthesized and successfully 3D-printed while their thermal conductivity was systematically studied.With the content of h-BN increasing from 0.1 wt%to 0.3 wt%,the thermal conductivity of the 3D-printed composites has been improved.Moreover,through the shear force given by the 3D printer,a complete thermal conductivity path is obtained inside the hydrogel,which significantly improves the thermal conductivity of the h-BN hydrogel composites.The maximum thermal conductivity is 0.8808 W/(m·K),leading to a thermal conductive enhancement of 1000%,compared with the thermal conductivity of pure PAA hydrogels.This study shows that using h-BN fillers can effectively and significantly improve the thermal conductivity of hydrogelbased materials while its 3D-printable ability has been maintained.展开更多
The development of tissue engineering and regeneration research has created new platforms for bone transplantation.However,the preparation of scaffolds with good fiber integrity is challenging,because scaffolds prepar...The development of tissue engineering and regeneration research has created new platforms for bone transplantation.However,the preparation of scaffolds with good fiber integrity is challenging,because scaffolds prepared by traditional printing methods are prone to fiber cracking during solvent evaporation.Human skin has an excellent natural heat-management system,which helps to maintain a constant body temperature through perspiration or blood-vessel constriction.In this work,an electrohydrodynamic-jet 3D-printing method inspired by the thermal-management system of skin was developed.In this system,the evaporation of solvent in the printed fibers can be adjusted using the temperature-change rate of the substrate to prepare 3D structures with good structural integrity.To investigate the solvent evaporation and the interlayer bonding of the fibers,finite-element analysis simulations of a three-layer microscale structure were carried out.The results show that the solvent-evaporation path is from bottom to top,and the strain in the printed structure becomes smaller with a smaller temperaturechange rate.Experimental results verified the accuracy of these simulation results,and a variety of complex 3D structures with high aspect ratios were printed.Microscale cracks were reduced to the nanoscale by adjusting the temperature-change rate from 2.5 to 0.5℃s-1.Optimized process parameters were selected to prepare a tissue engineering scaffold with high integrity.It was confirmed that this printed scaffold had good biocompatibility and could be used for bone-tissue regeneration.This simple and flexible 3D-printing method can also help with the preparation of a wide range of micro-and nanostructured sensors and actuators.展开更多
Organic-inorganic MoO_(3)/PI(MoPI)composites were prepared using a simple one-pot thermal copolymerization method.The resulting composites exhibited enhanced photocatalytic activity for the selective oxidation of benz...Organic-inorganic MoO_(3)/PI(MoPI)composites were prepared using a simple one-pot thermal copolymerization method.The resulting composites exhibited enhanced photocatalytic activity for the selective oxidation of benzylamine to N-benzylidene benzylamine(N-BDBA)in ambient air under simulated solar light irradiation compared to pristine MoO_(3) or polyimide(PI).In particular,the MoPI composite with a 0.3:1 molar ratio of Mo to melamine,referred to as MoPI-0.3,demonstrated the best performance in the photo-oxidation of benzylamine,achieving a benzylamine conversion of 95%with a N-BDBA selectivity exceeding 99%after 3 h irradiation.The enhanced photocatalytic activity of the MoPI-0.3 catalyst was attributed to the formation of a direct Z-scheme heterojunction between MoO_(3) and PI,facilitating more efficient separation of the photoinduced electrons and holes.Additionally,the MoPI-0.3 composite maintained considerably high activity over four consecutive cycles,highlighting its good stability and recyclability.Furthermore,the MoPI-0.3 composite could photo-oxidize benzylamine derivatives and heterocyclic amines to their corresponding imines,demonstrating the universal applicability of this composite catalyst.展开更多
With the rapid development of the electronics industry,the demand for dielectric materials with high permittivities,low losses,and excellent electrical breakdown strengths prepared via low-temperature fabrication tech...With the rapid development of the electronics industry,the demand for dielectric materials with high permittivities,low losses,and excellent electrical breakdown strengths prepared via low-temperature fabrication techniques is increasing.Herein,we propose a one-step cold sintering process route to improve the comprehensive performance of BaTiO_(3)−based ceramics by integrating polyetherimide(PEI).Dense BaTiO_(3)–PEI nanocomposites can be prepared via a cold sintering process at 250℃ using Ba(OH)_(2∙8)H_(2)O and H_(2)TiO_(3) as the transient liquid phase.The grain growth of BaTiO_(3) is inhibited,and thin PEI layers less than 10 nm in size are located at the grain boundaries.The dissolution‒precipitation process triggered by the transient liquid phase and viscous flow assisted by PEI dominates the cold sintering mechanism of the(1−x)BaTiO_(3)–xPEI nanocomposites.The dielectric properties are stable over a broad temperature range up to 200℃.Compared with BaTiO_(3),80%BaTiO_(3)–20%PEI has superior performance,with a relative permittivity of 163 and a low dielectric loss of 0.014,and the electrical breakdown strength is increased by 80.65%compared with BaTiO_(3).Overall,the cold sintering process provides a potential way to develop dielectric nanocomposites with excellent comprehensive performance.展开更多
Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale pr...Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale proposed in this work are used to simulate the thermal conductivity behaviors of the 3D C/SiC composites.An entirely new process is introduced to weave the preform with three-dimensional orthogonal architecture.The 3D steady-state analysis step is created for assessing the thermal conductivity behaviors of the composites by applying periodic temperature boundary conditions.Three RVE models of cuboid,hexagonal and fiber random distribution are respectively developed to comparatively study the influence of fiber package pattern on the thermal conductivities at the microscale.Besides,the effect of void morphology on the thermal conductivity of the matrix is analyzed by the void/matrix models.The prediction results at the mesoscale correspond closely to the experimental values.The effect of the porosities and fiber volume fractions on the thermal conductivities is also taken into consideration.The multi-scale models mentioned in this paper can be used to predict the thermal conductivity behaviors of other composites with complex structures.展开更多
The interfacial reaction behavior of Al and Ti_(3)AlC_(2)at different pouring temperatures and its effect on the microstructure and mechanical properties of the composites were investigated.The results show that the a...The interfacial reaction behavior of Al and Ti_(3)AlC_(2)at different pouring temperatures and its effect on the microstructure and mechanical properties of the composites were investigated.The results show that the addition of3.0 wt.%Ti_(3)AlC_(2)refines the average grain size ofα(Al)in the composite by 50.1%compared to Al6061 alloy.Morphological analyses indicate that an in-situ Al_(3Ti)transition layer of-180 nm in thickness is generated around the edge of Ti_(3)AlC_(2)at 720℃,forming a well-bonded Al-Al_(3Ti)interface.At this processing temperature,the ultimate tensile strength of A16061-3.0 wt.%Ti_(3)AlC_(2)composite is 199.2 MPa,an improvement of 41.5%over the Al6061 matrix.Mechanism analyses further elucidate that 720℃is favourable for forming the nano-sized transition layer at the Ti_(3)AlC_(2)edges.And,the thermal mismatch strengthening plays a dominant role in this state,with a strengthening contribution of about 74.8%.展开更多
In this work,flexible photothermal PVA/Ti_(2)O_(3) composite films with different amount(0 wt%,5 wt%,10 wt%,15 wt%)of Ti_(2)O_(3) particles modified by steric acid were prepared by a simple solution casting method.The...In this work,flexible photothermal PVA/Ti_(2)O_(3) composite films with different amount(0 wt%,5 wt%,10 wt%,15 wt%)of Ti_(2)O_(3) particles modified by steric acid were prepared by a simple solution casting method.The microstructures,XRD patterns,FTIR spectra,UV-Vis-NIR spectra thermo-conductivity,thermo-stability and photothermal effects of these composite films were all characterized.These results indicated that Ti_(2)O_(3) particles were well dispersed throughout the polyvinyl alcohol(PVA)matrix in the PVA/Ti_(2)O_(3) composite films.And Ti_(2)O_(3) particles could also effectively improve the photothermal properties of the composite films which exhibited high light absorption and generated a high temperature(about 57.4℃for film with 15 wt%Ti_(2)O_(3) amount)on the surface when it was irradiated by a simulated sunlight source(1 kW/m^(2)).展开更多
基金support of this research by the National Natural Science Foundation of China(Grant No.51909165,42177438)the Start-up Research Funding of Southwest Jiaotong University(YH1100312372222)+4 种基金the Fundamental Research Funds for the Central Universities(XJ2022003201)Science and Technology Program of Guangzhou(2019050001)National Key Research and Development Program of China(2019YFE0198000)the High-End Foreign Experts Project(G2021030016L)Pearl River Talent Program(2019QN01L951)
文摘Defect engineering can give birth to novel properties for adsorption and photocatalysis in the control of antibiotics and heavy metal combined pollution with photocatalytic composites.However,the role of defects and the process mechanism are complicated and indefinable.Herein,TiO_(2)/CN/3DC was fabricated and defects were introduced into the tripartite structure with separate O_(2)plasma treatment for the single component.We find that defect engineering can improve the photocatalytic activity,attributing to the increase of the contribution from h^(+)and OH.In contrast to TiO_(2)/CN/3DC with a photocatalytic tetracycline removal rate of 75.2%,the removal rate of TC with D-TiO_(2)/CN/3DC has increased to 88.5%.Moreover,the reactive sites of tetracycline can be increased by adsorbing on the defective composites.The defect construction on TiO_(2)shows the advantages in tetracycline degradation and Cu^(2+)adsorption,but also suffers significant inhibition for the tetracycline degradation in a tetracycline/Cu^(2+)combined system.In contrast,the defect construction on graphene can achieve the cooperative removal of tetracycline and Cu^(2+).These findings can provide new insights into water treatment strategies with defect engineering.
基金Funed by the National Key Research and Development Program of China(No.2021YFA0715700)the Open Fund of Hubei Longzhong Laboratory。
文摘Polyacrylic acid(PAA)hydrogel composites with different hexagonal boron nitride(h-BN)fillers were synthesized and successfully 3D-printed while their thermal conductivity was systematically studied.With the content of h-BN increasing from 0.1 wt%to 0.3 wt%,the thermal conductivity of the 3D-printed composites has been improved.Moreover,through the shear force given by the 3D printer,a complete thermal conductivity path is obtained inside the hydrogel,which significantly improves the thermal conductivity of the h-BN hydrogel composites.The maximum thermal conductivity is 0.8808 W/(m·K),leading to a thermal conductive enhancement of 1000%,compared with the thermal conductivity of pure PAA hydrogels.This study shows that using h-BN fillers can effectively and significantly improve the thermal conductivity of hydrogelbased materials while its 3D-printable ability has been maintained.
基金supported by the National Natural Science Foundation of China(Grant No.52105577)the Natural Science Foundation of Zhejiang Province(Grant Nos.LQ22E050001 and LQ21E080007)+1 种基金the Natural Science Foundation of Ningbo(Grant Nos.2021J088 and 2023J376)the Ningbo Yongjiang Talent Introduction Program(Grant No.2021A-137-G).
文摘The development of tissue engineering and regeneration research has created new platforms for bone transplantation.However,the preparation of scaffolds with good fiber integrity is challenging,because scaffolds prepared by traditional printing methods are prone to fiber cracking during solvent evaporation.Human skin has an excellent natural heat-management system,which helps to maintain a constant body temperature through perspiration or blood-vessel constriction.In this work,an electrohydrodynamic-jet 3D-printing method inspired by the thermal-management system of skin was developed.In this system,the evaporation of solvent in the printed fibers can be adjusted using the temperature-change rate of the substrate to prepare 3D structures with good structural integrity.To investigate the solvent evaporation and the interlayer bonding of the fibers,finite-element analysis simulations of a three-layer microscale structure were carried out.The results show that the solvent-evaporation path is from bottom to top,and the strain in the printed structure becomes smaller with a smaller temperaturechange rate.Experimental results verified the accuracy of these simulation results,and a variety of complex 3D structures with high aspect ratios were printed.Microscale cracks were reduced to the nanoscale by adjusting the temperature-change rate from 2.5 to 0.5℃s-1.Optimized process parameters were selected to prepare a tissue engineering scaffold with high integrity.It was confirmed that this printed scaffold had good biocompatibility and could be used for bone-tissue regeneration.This simple and flexible 3D-printing method can also help with the preparation of a wide range of micro-and nanostructured sensors and actuators.
基金supported by the Opening Project of Key Laboratory of Green Catalysis of Higher Education Institutes of Sichuan (LZJ2101)the Fundamental Research Funds of China West Normal University (19D038)
文摘Organic-inorganic MoO_(3)/PI(MoPI)composites were prepared using a simple one-pot thermal copolymerization method.The resulting composites exhibited enhanced photocatalytic activity for the selective oxidation of benzylamine to N-benzylidene benzylamine(N-BDBA)in ambient air under simulated solar light irradiation compared to pristine MoO_(3) or polyimide(PI).In particular,the MoPI composite with a 0.3:1 molar ratio of Mo to melamine,referred to as MoPI-0.3,demonstrated the best performance in the photo-oxidation of benzylamine,achieving a benzylamine conversion of 95%with a N-BDBA selectivity exceeding 99%after 3 h irradiation.The enhanced photocatalytic activity of the MoPI-0.3 catalyst was attributed to the formation of a direct Z-scheme heterojunction between MoO_(3) and PI,facilitating more efficient separation of the photoinduced electrons and holes.Additionally,the MoPI-0.3 composite maintained considerably high activity over four consecutive cycles,highlighting its good stability and recyclability.Furthermore,the MoPI-0.3 composite could photo-oxidize benzylamine derivatives and heterocyclic amines to their corresponding imines,demonstrating the universal applicability of this composite catalyst.
基金supported by the Natural Science Foundation of Shaanxi Province,China(No.2024JC-YBMS-349)the Guangdong Provincial Key Laboratory Program(No.2021B1212040001)the staff at the Instrument Analysis Centre of Xi’an Jiaotong University for the XRD,FT-IR,and TEM measurements.We also thank Xiaohua Cheng from the School of Materials Science and Engineering,Xi’an Jiaotong University for SEM measurements.
文摘With the rapid development of the electronics industry,the demand for dielectric materials with high permittivities,low losses,and excellent electrical breakdown strengths prepared via low-temperature fabrication techniques is increasing.Herein,we propose a one-step cold sintering process route to improve the comprehensive performance of BaTiO_(3)−based ceramics by integrating polyetherimide(PEI).Dense BaTiO_(3)–PEI nanocomposites can be prepared via a cold sintering process at 250℃ using Ba(OH)_(2∙8)H_(2)O and H_(2)TiO_(3) as the transient liquid phase.The grain growth of BaTiO_(3) is inhibited,and thin PEI layers less than 10 nm in size are located at the grain boundaries.The dissolution‒precipitation process triggered by the transient liquid phase and viscous flow assisted by PEI dominates the cold sintering mechanism of the(1−x)BaTiO_(3)–xPEI nanocomposites.The dielectric properties are stable over a broad temperature range up to 200℃.Compared with BaTiO_(3),80%BaTiO_(3)–20%PEI has superior performance,with a relative permittivity of 163 and a low dielectric loss of 0.014,and the electrical breakdown strength is increased by 80.65%compared with BaTiO_(3).Overall,the cold sintering process provides a potential way to develop dielectric nanocomposites with excellent comprehensive performance.
基金Supported by Science Center for Gas Turbine Project of China (Grant No.P2022-B-IV-014-001)Frontier Leading Technology Basic Research Special Project of Jiangsu Province of China (Grant No.BK20212007)the BIT Research and Innovation Promoting Project of China (Grant No.2022YCXZ019)。
文摘Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale proposed in this work are used to simulate the thermal conductivity behaviors of the 3D C/SiC composites.An entirely new process is introduced to weave the preform with three-dimensional orthogonal architecture.The 3D steady-state analysis step is created for assessing the thermal conductivity behaviors of the composites by applying periodic temperature boundary conditions.Three RVE models of cuboid,hexagonal and fiber random distribution are respectively developed to comparatively study the influence of fiber package pattern on the thermal conductivities at the microscale.Besides,the effect of void morphology on the thermal conductivity of the matrix is analyzed by the void/matrix models.The prediction results at the mesoscale correspond closely to the experimental values.The effect of the porosities and fiber volume fractions on the thermal conductivities is also taken into consideration.The multi-scale models mentioned in this paper can be used to predict the thermal conductivity behaviors of other composites with complex structures.
基金financially supported by the National Natural Science Foundation of China(No.51965040)Science and Technology Project of Jiangxi Provincial Department of Transportation,China(No.2022H0048)。
文摘The interfacial reaction behavior of Al and Ti_(3)AlC_(2)at different pouring temperatures and its effect on the microstructure and mechanical properties of the composites were investigated.The results show that the addition of3.0 wt.%Ti_(3)AlC_(2)refines the average grain size ofα(Al)in the composite by 50.1%compared to Al6061 alloy.Morphological analyses indicate that an in-situ Al_(3Ti)transition layer of-180 nm in thickness is generated around the edge of Ti_(3)AlC_(2)at 720℃,forming a well-bonded Al-Al_(3Ti)interface.At this processing temperature,the ultimate tensile strength of A16061-3.0 wt.%Ti_(3)AlC_(2)composite is 199.2 MPa,an improvement of 41.5%over the Al6061 matrix.Mechanism analyses further elucidate that 720℃is favourable for forming the nano-sized transition layer at the Ti_(3)AlC_(2)edges.And,the thermal mismatch strengthening plays a dominant role in this state,with a strengthening contribution of about 74.8%.
基金Funded by the Youth Backbone Teacher Training Plan in University of Henan Province(No.21220028)Science and Technology Research Project of Henan Province(No.242102321066)+2 种基金Natural Science Foundation of Henan Province(No.232300420312)Henan University of Technology Young Backbone Teacher Training Plan(No.21421260)the Innovation Training Program for College Students in Henan Province(No.202310463046)。
文摘In this work,flexible photothermal PVA/Ti_(2)O_(3) composite films with different amount(0 wt%,5 wt%,10 wt%,15 wt%)of Ti_(2)O_(3) particles modified by steric acid were prepared by a simple solution casting method.The microstructures,XRD patterns,FTIR spectra,UV-Vis-NIR spectra thermo-conductivity,thermo-stability and photothermal effects of these composite films were all characterized.These results indicated that Ti_(2)O_(3) particles were well dispersed throughout the polyvinyl alcohol(PVA)matrix in the PVA/Ti_(2)O_(3) composite films.And Ti_(2)O_(3) particles could also effectively improve the photothermal properties of the composite films which exhibited high light absorption and generated a high temperature(about 57.4℃for film with 15 wt%Ti_(2)O_(3) amount)on the surface when it was irradiated by a simulated sunlight source(1 kW/m^(2)).
