We synthesized BiVO_(4)mesocrystals with ordered assembly structure,and studied the structural order and the relationship between the photodegradation of Rhodamine B.Au nanoparticles(NPs)were successfully loaded onto ...We synthesized BiVO_(4)mesocrystals with ordered assembly structure,and studied the structural order and the relationship between the photodegradation of Rhodamine B.Au nanoparticles(NPs)were successfully loaded onto Meso-BiVO_(4)by light-assisted induction,and Cd nanoparticles were further selected to be deposited on Au nanoparticles to form Z-scheme photocatalyst Meso-BiVO_(4)-Au-CdS heterostructures.We try and propose to analyze its ordered assembly structure by XRD for the first time.The results show that Meso-BiVO_(4)is a mesocrystal with highly exposed(001)plane and directional assembly structure.The charge separation efficiency of all samples was studied by PL spectroscopy.The results show that the Z-scheme Meso-BiVO_(4)-Au-CdS can promote the charge separation and obtain the best carrier separation efficiency.Thus,it has the best photocatalytic activity in the experiment of photocatalytic degradation of rhodamine B.The main active species in the degradation process were confirmed by free radical trapping experiment,and the degradation mechanism was put forward.展开更多
The(TiNbTaZrHf)C high entropy carbide(HEC)was successfully synthesized by complete commercial transition metal powders,obtained fine sintered bulks without additives by in-situ reaction element synthesis method.(TiNbT...The(TiNbTaZrHf)C high entropy carbide(HEC)was successfully synthesized by complete commercial transition metal powders,obtained fine sintered bulks without additives by in-situ reaction element synthesis method.(TiNbTaZrHf)C bulk shows a face centered cubic rock salt structure with homogeneous single-phase FCC structure in composition and structure.The optimum sintering temperature is about 1900℃at which the best mechanical properties are obtained.The mechanical properties of(TiNbTaZrHf)C ceramic block are better than those of binary transition metal carbides,and it has obvious high entropy effect.Adding a small amount of Al as sintering additive,the mechanical properties of(TiNbTaZrHf)C ceramics continue to improve,the bending strength of the samples at each temperature is increased by at least 38%,and the highest is 486 MPa.The elastic modulus and hardness of the sample at 1900℃are also slightly increased by 4%and 14%,respectively.The above conclusions illustrate that the properties of high entropy ceramics are greatly improved by in-situ reaction sintering.展开更多
High quality nano-sized zirconium carbide （ZrC） powders were successfully fabricated via a developed chemical active dilution self-propagating high-temperature synthesis （SHS） method assisted by ball milling pretr...High quality nano-sized zirconium carbide （ZrC） powders were successfully fabricated via a developed chemical active dilution self-propagating high-temperature synthesis （SHS） method assisted by ball milling pretreatment process using traditional cheap zirconium dioxide powder （ZrO2）, magnesium powder （Mg） and sucrose （C12H22Oll） as raw materials. FSEM, TEM, HRTEM, SAED, XRD, FTIR and Raman, ICP- AES, laser particle size analyzer, oxygen and nitrogen analyzer, carbon/sulfur determinator and TG-DSC were employed for the characterization of the morphology, structure, chemical composition and thermal stability of the as-synthesized ZrC samples. The as-synthesized samples demonstrated high purity, low oxygen content and evenly distributed ZrC nano-powders with an average particle size of 50nm. In addition, the effects of endothermic rate and the possible chemical reaction mechanism were also discussed.展开更多
A high-pressure hot-pressing process was applied to densify a commercial boron carbide-titanium diboride (B4C-TiB2) powder mixture.Nearly fully dense (98.6%) materials were obtained at 1700℃ under a pressure of 100MP...A high-pressure hot-pressing process was applied to densify a commercial boron carbide-titanium diboride (B4C-TiB2) powder mixture.Nearly fully dense (98.6%) materials were obtained at 1700℃ under a pressure of 100MPa.Compared to the sintering temperature required to achieve similar results when a pressure of only 30MPa was applied,the sintering temperature was found to decrease by about 200℃ under pressure of 100 MPa.Analysis of the thermodynamics and microstructure showed that the plastic deformation of the B4C grains induced by high pressure dominated the densification mechanism when high pressure was applied.Furthermore,higher pressure resulted in remarkably improved mechanical properties of the composites,which could be traced back to the generation of stacking faults in the B4C grains and aggregation of TiB2.展开更多
The damage mechanism and energy dissipation of the Polyethylene (PE) laminates in impacting was investigated. It was found that the dissipated energy of the impacting sphere bullet by the 1-mmthick PE plate firstly in...The damage mechanism and energy dissipation of the Polyethylene (PE) laminates in impacting was investigated. It was found that the dissipated energy of the impacting sphere bullet by the 1-mmthick PE plate firstly increased with the impacting velocity increasing from 50 to about 300 m/s, and then decreased with the impacting velocity increasing up to 600 m/s. According to the measured deformation and damage degree, a numerical simulation of the dissipated energy was made and obvious offset was found with the experimental results. The quasi-static properties of the PE fibers, decreasing with increase in tensile velocity, may be the main reason for the offset.展开更多
Nest-like and multilayered-disk-like Bi2WO6 photocatalysts were synthesized through a hydrothermal strategy using thiourea and acetic acid as complexing agents. The nest-like Bi2WO6 showed excellent visible-light-driv...Nest-like and multilayered-disk-like Bi2WO6 photocatalysts were synthesized through a hydrothermal strategy using thiourea and acetic acid as complexing agents. The nest-like Bi2WO6 showed excellent visible-light-driven photocatalytic performance, and it could decompose rhodamine B（RhB） within 100 minutes. This excellent performance resulted from its special microstructure and the relatively large surface area.展开更多
Using chitin as the templating material,we obtained layered nanocomposites like shrimp or crab shells via a sol-gel self-assembly process.SEM images show a layered structure and XRD patterns present a typical peak of ...Using chitin as the templating material,we obtained layered nanocomposites like shrimp or crab shells via a sol-gel self-assembly process.SEM images show a layered structure and XRD patterns present a typical peak of chitin,which indicates the templating role of chitin in the as-received hybrid samples.Additionally,the layer spacing of chitin/silica hybrid materials is reduced with increasing content of silica.After the heat treatment for carbonization,layered SiOC nanocomposites with mesoporous structures were obtained and showed good dye adsorption performance.The present study demonstrates a reliable and self-assembly synthesis technique for the development of advanced high-performance nanocomposites with biomimetic nanostructures.展开更多
A recombinant protein ChiSifiCa,which was originally designed for regulation of calcium carbonate,was utilized to direct the mineralization of PbI_(2).By the regulation of ChiSifiCa protein,PbI_(2)nanoparticles compos...A recombinant protein ChiSifiCa,which was originally designed for regulation of calcium carbonate,was utilized to direct the mineralization of PbI_(2).By the regulation of ChiSifiCa protein,PbI_(2)nanoparticles composed of crystalline nanoflakes and amorphous nanorods were fabricated under environmental benign conditions.Synthetic PbI_(2)was successfully applied for preparation of perovskite precursors to fabricate solar cells.This regulation of ChiSifiCa on PbI_(2)improves the power conversion efficiency of corresponding perovskite solar cells to 16%.The present study may open a new avenue in the design and synthesis of materials with novel structures and functions.展开更多
A novel aqueous Sn-S complex solution was applied as precursor to fabricate SnO2 electron selective layers (ESLs) for the hybrid perovskite solar cells (PSCs).The tin and sulfur powder were directly dissolved in a (NH...A novel aqueous Sn-S complex solution was applied as precursor to fabricate SnO2 electron selective layers (ESLs) for the hybrid perovskite solar cells (PSCs).The tin and sulfur powder were directly dissolved in a (NH4)2S water solution to form Sn-S precursor.After depositon and annealing,the SnO2 film was formed,presenting as a low cost and enviromental friendly method for preparation of ESL.The films showed excellent transmittance at visible wavelength range.Moreover,the method exhibited high compatibility for doping using Cu,Cd,Li,and Zn elements.Zn doping (0.05 M) in the as-prepared SnO2 ESL significantly improved perovskite solar cells (PSCs) performance.The highest PCE of 13.17% was achived with 15% enhancement compared to that of undoped SnO2 ESL samples.TiCl4 modifications on SnO2 film improved photovoltaic performance to 14.45%,but resulted in the poor long-term stability,around 80% more degredation than that of PSCs based on Zn-doped SnO2 films.展开更多
Dense Nb/Nb5Si3 composites were fabricated via spark plasma sintering technology using Nb, Si, and Al elemental powders as raw materials. The microstructttres of the synthesised composites were analyzed through scanni...Dense Nb/Nb5Si3 composites were fabricated via spark plasma sintering technology using Nb, Si, and Al elemental powders as raw materials. The microstructttres of the synthesised composites were analyzed through scanning electron microscopy, X-ray diffraction, and electron probe microanalysis. The results show that the composites consisted of residual Nb particle phase and Nb5Si3 phase. The microstructure of the Nb/ Nb5Si3 in situ composites was evidently affected by Al addition, which prompted the formation of the Al3Nb10Si3 phase. In addition, the Rockwell hardness of the composites decreased with the increase in AI additions. The Rockwell hardness of Nb-20Si is 60HRC, which decreased to approximately 52.7 HRC when the Al content increased to 15 at%. The oxidation resistance of the Nb/NbsSi3 in situ composites significantly improved with the increase in Al addition.展开更多
Homogeneous hollow Cu20 octahedral nanostructures have been fabricated by a facile onepot reduction reaction at roomtemperature. The microscope analysis revealed that the edges of as-prepared hollow structures were ar...Homogeneous hollow Cu20 octahedral nanostructures have been fabricated by a facile onepot reduction reaction at roomtemperature. The microscope analysis revealed that the edges of as-prepared hollow structures were around 200 nm with a wall thickness of about 20 nm. To investigate the influence factors and formation mechanism of the hollow octahedral structure, samples subjected to different reaction conditions were studies. The results showed that the morphology and structures of Cu20 particles were greatly affected by the concentration of pH value of the reaction environment and the reaction time. Ostwald ripening process is orooosed to exolain the growth mechanism of the hollow octahedral nanostructures.展开更多
文摘We synthesized BiVO_(4)mesocrystals with ordered assembly structure,and studied the structural order and the relationship between the photodegradation of Rhodamine B.Au nanoparticles(NPs)were successfully loaded onto Meso-BiVO_(4)by light-assisted induction,and Cd nanoparticles were further selected to be deposited on Au nanoparticles to form Z-scheme photocatalyst Meso-BiVO_(4)-Au-CdS heterostructures.We try and propose to analyze its ordered assembly structure by XRD for the first time.The results show that Meso-BiVO_(4)is a mesocrystal with highly exposed(001)plane and directional assembly structure.The charge separation efficiency of all samples was studied by PL spectroscopy.The results show that the Z-scheme Meso-BiVO_(4)-Au-CdS can promote the charge separation and obtain the best carrier separation efficiency.Thus,it has the best photocatalytic activity in the experiment of photocatalytic degradation of rhodamine B.The main active species in the degradation process were confirmed by free radical trapping experiment,and the degradation mechanism was put forward.
基金Funded by the National Natural Science Foundation of China(Nos.43190311,43200301,and 631800611)。
文摘The(TiNbTaZrHf)C high entropy carbide(HEC)was successfully synthesized by complete commercial transition metal powders,obtained fine sintered bulks without additives by in-situ reaction element synthesis method.(TiNbTaZrHf)C bulk shows a face centered cubic rock salt structure with homogeneous single-phase FCC structure in composition and structure.The optimum sintering temperature is about 1900℃at which the best mechanical properties are obtained.The mechanical properties of(TiNbTaZrHf)C ceramic block are better than those of binary transition metal carbides,and it has obvious high entropy effect.Adding a small amount of Al as sintering additive,the mechanical properties of(TiNbTaZrHf)C ceramics continue to improve,the bending strength of the samples at each temperature is increased by at least 38%,and the highest is 486 MPa.The elastic modulus and hardness of the sample at 1900℃are also slightly increased by 4%and 14%,respectively.The above conclusions illustrate that the properties of high entropy ceramics are greatly improved by in-situ reaction sintering.
基金Funded by the Program for New Century Excellent Talents in University(No.NCET-12-0655)the Guangxi Natural Science Foundation(No.2014GXNSFFA118004)the Self-determined and Innovative Research Funds of WUT(Nos.136643002 and No.2013IV058)
文摘High quality nano-sized zirconium carbide （ZrC） powders were successfully fabricated via a developed chemical active dilution self-propagating high-temperature synthesis （SHS） method assisted by ball milling pretreatment process using traditional cheap zirconium dioxide powder （ZrO2）, magnesium powder （Mg） and sucrose （C12H22Oll） as raw materials. FSEM, TEM, HRTEM, SAED, XRD, FTIR and Raman, ICP- AES, laser particle size analyzer, oxygen and nitrogen analyzer, carbon/sulfur determinator and TG-DSC were employed for the characterization of the morphology, structure, chemical composition and thermal stability of the as-synthesized ZrC samples. The as-synthesized samples demonstrated high purity, low oxygen content and evenly distributed ZrC nano-powders with an average particle size of 50nm. In addition, the effects of endothermic rate and the possible chemical reaction mechanism were also discussed.
基金the National Natural Science Foundation of China(51672197)。
文摘A high-pressure hot-pressing process was applied to densify a commercial boron carbide-titanium diboride (B4C-TiB2) powder mixture.Nearly fully dense (98.6%) materials were obtained at 1700℃ under a pressure of 100MPa.Compared to the sintering temperature required to achieve similar results when a pressure of only 30MPa was applied,the sintering temperature was found to decrease by about 200℃ under pressure of 100 MPa.Analysis of the thermodynamics and microstructure showed that the plastic deformation of the B4C grains induced by high pressure dominated the densification mechanism when high pressure was applied.Furthermore,higher pressure resulted in remarkably improved mechanical properties of the composites,which could be traced back to the generation of stacking faults in the B4C grains and aggregation of TiB2.
基金Funded by National Natural Science Foundation of China(No.51502220)
文摘The damage mechanism and energy dissipation of the Polyethylene (PE) laminates in impacting was investigated. It was found that the dissipated energy of the impacting sphere bullet by the 1-mmthick PE plate firstly increased with the impacting velocity increasing from 50 to about 300 m/s, and then decreased with the impacting velocity increasing up to 600 m/s. According to the measured deformation and damage degree, a numerical simulation of the dissipated energy was made and obvious offset was found with the experimental results. The quasi-static properties of the PE fibers, decreasing with increase in tensile velocity, may be the main reason for the offset.
基金Funded by the National Natural Science Foundation of China(A3 Foresight Project No.50821140308)
文摘Nest-like and multilayered-disk-like Bi2WO6 photocatalysts were synthesized through a hydrothermal strategy using thiourea and acetic acid as complexing agents. The nest-like Bi2WO6 showed excellent visible-light-driven photocatalytic performance, and it could decompose rhodamine B（RhB） within 100 minutes. This excellent performance resulted from its special microstructure and the relatively large surface area.
基金by the Opening Funding of the State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology(P2020-010)the National Natural Science Foundation of China(Nos.51521001 and 51832003)。
文摘Using chitin as the templating material,we obtained layered nanocomposites like shrimp or crab shells via a sol-gel self-assembly process.SEM images show a layered structure and XRD patterns present a typical peak of chitin,which indicates the templating role of chitin in the as-received hybrid samples.Additionally,the layer spacing of chitin/silica hybrid materials is reduced with increasing content of silica.After the heat treatment for carbonization,layered SiOC nanocomposites with mesoporous structures were obtained and showed good dye adsorption performance.The present study demonstrates a reliable and self-assembly synthesis technique for the development of advanced high-performance nanocomposites with biomimetic nanostructures.
基金Supported by the National Natural Science Foundation of China(Nos.51521001,51832003)。
文摘A recombinant protein ChiSifiCa,which was originally designed for regulation of calcium carbonate,was utilized to direct the mineralization of PbI_(2).By the regulation of ChiSifiCa protein,PbI_(2)nanoparticles composed of crystalline nanoflakes and amorphous nanorods were fabricated under environmental benign conditions.Synthetic PbI_(2)was successfully applied for preparation of perovskite precursors to fabricate solar cells.This regulation of ChiSifiCa on PbI_(2)improves the power conversion efficiency of corresponding perovskite solar cells to 16%.The present study may open a new avenue in the design and synthesis of materials with novel structures and functions.
基金the National Key Research and Development Plan(2017YFE0131900)the Hubei Provincial Natural Science Foundation of China(2016CFB464)+2 种基金the Fundamental Research Funds for the Central Universities(WUT:2016IVA089,2016III030)the Hubei Key Laboratory of Low Dimensional Optoelectronic Material and Devices(HLOM151002)“Chutian Scholar Program”of Hubei Province,China。
文摘A novel aqueous Sn-S complex solution was applied as precursor to fabricate SnO2 electron selective layers (ESLs) for the hybrid perovskite solar cells (PSCs).The tin and sulfur powder were directly dissolved in a (NH4)2S water solution to form Sn-S precursor.After depositon and annealing,the SnO2 film was formed,presenting as a low cost and enviromental friendly method for preparation of ESL.The films showed excellent transmittance at visible wavelength range.Moreover,the method exhibited high compatibility for doping using Cu,Cd,Li,and Zn elements.Zn doping (0.05 M) in the as-prepared SnO2 ESL significantly improved perovskite solar cells (PSCs) performance.The highest PCE of 13.17% was achived with 15% enhancement compared to that of undoped SnO2 ESL samples.TiCl4 modifications on SnO2 film improved photovoltaic performance to 14.45%,but resulted in the poor long-term stability,around 80% more degredation than that of PSCs based on Zn-doped SnO2 films.
基金Funded by National Natural Science Foundation of China(No.51271091)Science Project of Jiangxi Ministry of Education of China(No.GJJ12420)
文摘Dense Nb/Nb5Si3 composites were fabricated via spark plasma sintering technology using Nb, Si, and Al elemental powders as raw materials. The microstructttres of the synthesised composites were analyzed through scanning electron microscopy, X-ray diffraction, and electron probe microanalysis. The results show that the composites consisted of residual Nb particle phase and Nb5Si3 phase. The microstructure of the Nb/ Nb5Si3 in situ composites was evidently affected by Al addition, which prompted the formation of the Al3Nb10Si3 phase. In addition, the Rockwell hardness of the composites decreased with the increase in AI additions. The Rockwell hardness of Nb-20Si is 60HRC, which decreased to approximately 52.7 HRC when the Al content increased to 15 at%. The oxidation resistance of the Nb/NbsSi3 in situ composites significantly improved with the increase in Al addition.
基金Funded by the Fundamental Research Funds for the Central Universities (No.123201003)
文摘Homogeneous hollow Cu20 octahedral nanostructures have been fabricated by a facile onepot reduction reaction at roomtemperature. The microscope analysis revealed that the edges of as-prepared hollow structures were around 200 nm with a wall thickness of about 20 nm. To investigate the influence factors and formation mechanism of the hollow octahedral structure, samples subjected to different reaction conditions were studies. The results showed that the morphology and structures of Cu20 particles were greatly affected by the concentration of pH value of the reaction environment and the reaction time. Ostwald ripening process is orooosed to exolain the growth mechanism of the hollow octahedral nanostructures.
