Rechargeable lithium–oxygen batteries have been considered as a promising energy storage technology because of their ultra-high theoretical energy densities which are comparable to gasoline. In order to improve the e...Rechargeable lithium–oxygen batteries have been considered as a promising energy storage technology because of their ultra-high theoretical energy densities which are comparable to gasoline. In order to improve the electrochemical properties of lithium–oxygen batteries(LOBs), especially the cycling performance, a high-efficiency cathode catalyst is the most important component.Hence, we aim to demonstrate that CuCr_2O_4@rGO(CCO@rGO) nanocomposites, which are synthesized using a facile hydrothermal method and followed by a series of calcination processes, are an effective cathode catalyst. The obtained CCO@rGO nanocomposites which served as the cathode catalyst of the LOBs exhibited an outstanding cycling performance for over 100 cycles with a fixed capacity of 1000 mAh g^(-1) at a current density of 200 mA g^(-1). The enhanced properties were attributed to the synergistic effect between the high catalytic efficiency of the spinel-structured CCO nanoparticles, the high specific surface area, and high conductivity of the rGO.展开更多
通过共沉淀法合成了CuCr_(2)O_(4)黑色颜料。研究了沉淀剂(即尿素、氨水、氢氧化钠)对相组成和颜色性能的影响。同时,计算了以氨水和氢氧化钠为沉淀剂时CuCr_(2)O_(4)的结晶动力学和结晶机制。结果表明,由于两种离子(Cu^(2+)和Cr^(3+))...通过共沉淀法合成了CuCr_(2)O_(4)黑色颜料。研究了沉淀剂(即尿素、氨水、氢氧化钠)对相组成和颜色性能的影响。同时,计算了以氨水和氢氧化钠为沉淀剂时CuCr_(2)O_(4)的结晶动力学和结晶机制。结果表明,由于两种离子(Cu^(2+)和Cr^(3+))的溶解度不同,沉淀过程的最佳pH值为7.5;由于产物中存在Cr2O3,尿素不适合作为沉淀剂。氨水作为沉淀剂时,CuCr_(2)O_(4)结晶的活化能为120.2 k J/mol,氢氧化钠作为沉淀剂时为141.3 k J/mol。CuCr_(2)O_(4)的结晶过程涉及成核和三维生长。较小的结晶活化能得到的CuCr_(2)O_(4)颗粒细小,分散均匀,呈色性能更优异。展开更多
High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and ferromagnetic cobalt ferrite(CoFe_(2)O_(4))(0.00 wt%to 0.2 wt%)are prepared by a solution casting method acc...High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and ferromagnetic cobalt ferrite(CoFe_(2)O_(4))(0.00 wt%to 0.2 wt%)are prepared by a solution casting method accompanied by uniaxial stretching and high electric field poling.The decisive effect of the poling electric field on the power generating capability was confirmed by the experiments.For pure PVDF-HFP films,when the maximum electric field Emax is 120 MV/m,the calibrated open circuit voltage reaches 2.93 V,which is much higher than those poled at lower electric fields(70 MV/m:1.41 V;90 MV/m:2.11 V).Furthermore,the addition of CoFe_(2)O_(4)also influences the piezoelectricity dramatically.In the samples containing 0.15 wt%CoFe_(2)O_(4),the calibrated open circuit voltage increases to the maximum value of 3.57 V.Meanwhile,the relative fraction of theβ-phase and the crystallinity degree are 99%and 48%,respectively.The effects of CoFe_(2)O_(4)nanoparticles on initial crystallization,uniaxial stretching and high electric field poling are investigated by XRD,FTIR and DSC.展开更多
The(1-x)NiCo_(2)O_(4)/x PbS(0≤x≤0.2)nanocomposite samples are synthesized using the hydrothermal and thermolysis procedures.The different phases developed in the obtained nanocomposite samples are accurately determi...The(1-x)NiCo_(2)O_(4)/x PbS(0≤x≤0.2)nanocomposite samples are synthesized using the hydrothermal and thermolysis procedures.The different phases developed in the obtained nanocomposite samples are accurately determined using the x-ray diffraction technique equipped with a line-detector.The percentage of the formed phases(NiCo_(2)O_(4)(NCO),PbS,PbSO_(4)),structural and microstructure parameters are determined using Rietveld quantitative phase analysis.The transmission electron microscope(TEM)images and Rietveld analysis reveal almost isotropic particle size in the nano range with a very narrow size distribution.The obtained phase percentage of PbS and PbSO4are smaller than nominated values(x)suggesting dissolving of some Pb and S ions into NCO which is then confirmed by the analysis of Fourier-transform infrared(FTIR)spectra of nanocomposite samples.The absorption spectra are modified upon doping NCO with PbS.The optical band gaps of the nanocomposites increase as the amount of PbS augments.The effect of alloying on extinction coefficient,refractive index,dielectric constant,optical conductivity,the intensity,and emitted color from the photoluminescence of the nanocomposite samples are also studied.The refractive index value of NCO and NCO-PbS nanocomposite samples exhibit normal dispersions.The photoluminescent measurements reveal that the NCO-PbS nanocomposites can emit a violet color.The improvement in the values of the nonlinear optical(NLO)parameters of pristine NCO at high frequencies or the nanocomposite samples at low frequencies,are made them used in NLO photonic devices.展开更多
Rational design of oxygen evolution reaction(OER)catalysts at low cost would greatly benefit the economy.Taking advantage of earth-abundant elements Si,Co and Ni,we produce a unique-structure where cobalt-nickel silic...Rational design of oxygen evolution reaction(OER)catalysts at low cost would greatly benefit the economy.Taking advantage of earth-abundant elements Si,Co and Ni,we produce a unique-structure where cobalt-nickel silicate hydroxide[Co_(2.5)Ni_(0.5)Si_(2)O_(5)(OH)_(4)]is vertically grown on a reduced graphene oxide(rGO)support(CNS@rGO).This is developed as a low-cost and prospective OER catalyst.Compared to cobalt or nickel silicate hydroxide@rGO(CS@rGO and NS@rGO,respectively)nanoarrays,the bimetal CNS@rGO nanoarray exhibits impressive OER performance with an overpotential of 307 mV@10 mA cm^(-2).This value is higher than that of CS@rGO and NS@rGO.The CNS@rGO nanoarray has an overpotential of 446 mV@100 mA cm^(-2),about 1.4 times that of the commercial RuO_(2)electrocatalyst.The achieved OER activity is superior to the state-of-the-art metal oxides/hydroxides and their derivatives.The vertically grown nanostructure and optimized metal-support electronic interactions play an indispensable role for OER performance improvement,including a fast electron transfer pathway,short proton/electron diffusion distance,more active metal centers,as well as optimized dualatomic electron density.Taking advantage of interlay chemical regulation and the in-situ growth method,the advanced-structural CNS@rGO nanoarrays provide a new horizon to the rational and flexible design of efficient and promising OER electrocatalysts.展开更多
The effective,stable,and secure catalysts are essential for sulfate radical(SO_(4)·−)-based advanced oxidation processes(SR-AOPs)to the degradation of organic contaminants in water.Heterogeneous supported cobalt-...The effective,stable,and secure catalysts are essential for sulfate radical(SO_(4)·−)-based advanced oxidation processes(SR-AOPs)to the degradation of organic contaminants in water.Heterogeneous supported cobalt-based catalysts are commonly used to activate peroxymonosulfate(PMS)to achieve the degradation.In this work,we synthesized Co_(3)O_(4)@Al_(2)O_(3)three-dimensional(3D)mesoporous nanocomposite(denoted as Co_(3)O_(4)@Al_(2)O_(33)DPNC)in just one step by calcining cheap and green deep eutectic solvent(DES)solution containing Co salt.Co_(3)O_(4)@Al_(2)O_(33)DPNC with the high specific surface area(93.246 m^(2)/g),uniform pore distribution(3.829 nm)and rich porosity(0.255 cm^(3)/g)were attained in a beautiful hierarchical structure which exhibited the open 3D propeller-like microstructure,two-dimensional lamellar substructure with rich folds,as well as the decoration of highly dispersed Co_(3)O_(4)nanoparticles on mesoporous amorphous Al_(2)O_(3).The excellent chemical and thermal stability of Al_(2)O_(3)ensures the high stability of the catalyst,and the formation of the complex hierarchical structure makes the active Co_(3)O_(4)be homogenously dispersed for effective catalysis.The catalyst demonstrated outstanding performance for catalytic degradations of organic pollutants(acetaminophen,oxytetracycline,5-sulfosalicylic acid,orange G and Rhodamine B)by generated SO_(4)·−,·OH and^(1)O_(2).With a very low cobalt content(equal to 28.2 mg/L of Co),the catalyst exhibited very high stability and excellent reusability in the recycling usages,while the leaching of the cobalt element(<0.145 mg/L)was also at a low level.Our catalyst achieved effective degradations of acetaminophen in cycles without losing its stable hierarchical nanostructure.展开更多
High-efficiency electromagnetic interference(EMI)shielding materials are of great importance for electronic equipment reliability,information security and human health.In this work,bidirectional aligned Ti_(3)C_(2)T_(...High-efficiency electromagnetic interference(EMI)shielding materials are of great importance for electronic equipment reliability,information security and human health.In this work,bidirectional aligned Ti_(3)C_(2)T_(x)@Fe_(3)O_(4)/CNF aerogels(BTFCA)were firstly assembled by bidirectional freezing and freeze-drying technique,and the BTFCA/epoxy nanocomposites with long-range aligned lamellar structures were then prepared by vacuum-assisted impregnation of epoxy resins.Benefitting from the successful construction of bidirectional aligned three-dimensional conductive networks and electromagnetic synergistic effect,when the mass fraction of Ti_(3)C_(2)T_(x) and Fe_(3)O_(4) are 2.96 and 1.48 wt%,BTFCA/epoxy nanocomposites show outstanding EMI shield-ing effectiveness of 79 dB,about 10 times of that of blended Ti_(3)C_(2)T_(x)@Fe_(3)O_(4)/epoxy(8 dB)nanocomposites with the same loadings of Ti_(3)C_(2)T_(x) and Fe_(3)O_(4).Meantime,the corresponding BTFCA/epoxy nanocomposites also present excellent thermal stability(T_(heat-resistance index) of 198.7℃)and mechanical properties(storage modulus of 9902.1 MPa,Young’s modulus of 4.51 GPa and hardness of 0.34 GPa).Our fabricated BTFCA/epoxy nanocomposites would greatly expand the applications of MXene and epoxy resins in the fields of information security,aerospace and weapon manufacturing,etc.展开更多
A Ag@CuFe_(2)O_(4)@TiO_(2) nanocomposite film with high performance of photogenerated cathodic protection was prepared by hydrothermal and photoreduction methods.The results showed that when the CuFe_(2)O_(4) hydrothe...A Ag@CuFe_(2)O_(4)@TiO_(2) nanocomposite film with high performance of photogenerated cathodic protection was prepared by hydrothermal and photoreduction methods.The results showed that when the CuFe_(2)O_(4) hydrothermal reaction time was 6 h and the AgNO_(3) concentration was 0.1 M,the Ag@CuFe_(2)O_(4)@TiO_(2) nanocomposite material performed the best cathodic protection capability for 304 stainless steel(304SS).In this case,the protective potential achieved-930 mV(versus SCE)associated with the photocurrent density of 475μA/cm^(2),which was 14.8 times that of pure TiO_(2) nanowires.In the dark,the nanocomposite provided cathodic protection of up to 485 mV for 304SS.Due to the heterogeneous junctions at the two interfaces among the three kinds of nanocomposite materials,the build-in electric field was fabricated,which promoted the separation efficiency of photogenerated electrons and holes and effectively improved the photochemical cathodic protection of 304SS.展开更多
The development of novel anode materials,with superior rate capability,is of utmost significance for the successful realization of sodium-ion batteries(SIBs).Herein,we present a nanocomposite of Nb_(2)O_(5)and reduced...The development of novel anode materials,with superior rate capability,is of utmost significance for the successful realization of sodium-ion batteries(SIBs).Herein,we present a nanocomposite of Nb_(2)O_(5)and reduced graphene oxide(rGO)by using hydrothermal-assisted microemulsion route.The water-in-oil microemulsion formed nanoreactors,which restrained the particle size of Nb_(2)O_(5)and shortened the diffusion length of ions.Moreover,the rGO network prevented agglomeration of Nb_(2)O_(5)nanoparticles and improved electronic conductivity.Consequently,Nb_(2)O_(5)@rGO nanocomposite is employed as anode material in SIBs,delivering a capacity of 195 mAh/g after 200 charge/discharge cycles at 0.2 A/g.Moreover,owing to conductive rGO network,the Nb_(2)O_(5)@rGO electrode rende red a specific capacity of 76 mAh/g at high current density of 10 A/g and maintained 98 mAh/g after 1000 charge/discharge cycles at 2 A/g.The Nb_(2)O_(5)@rGO electrode material prepared by microemulsion method shows promising possibilities for application of SIBs.展开更多
A new vertically aligned nanocomposite(VAN)structure based on two-dimensional(2D)layered oxides has been designed and self-assembled on both LaAlO_(3)(001)and SrTiO3(001)substrates.The new VAN structure consists of ep...A new vertically aligned nanocomposite(VAN)structure based on two-dimensional(2D)layered oxides has been designed and self-assembled on both LaAlO_(3)(001)and SrTiO3(001)substrates.The new VAN structure consists of epitaxially grown Co_(3)O_(4) nanopillars embedded in the Bi_(2)WO_(6) matrix with a unique 2D layered structure,as evidenced by the microstructural analysis.Physical property measurements show that the new Bi_(2)WO_(6)-Co_(3)O_(4) VAN structure exhibits strong ferromagnetic and piezoelectric response at room temperature as well as anisotropic permittivity response.This work demonstrates a new approach in processing multifunctional VANs structure based on the layered oxide systems towards future nonlinear optics,ferromagnets,and multiferroics.展开更多
The low surface area,high recombination rate of photogenerated charge carriers,narrow visible range activity,and difficulty in the separation from cleaned solutions limit the wide application of g-C_(3)N_(4) as a phot...The low surface area,high recombination rate of photogenerated charge carriers,narrow visible range activity,and difficulty in the separation from cleaned solutions limit the wide application of g-C_(3)N_(4) as a photocatalyst.Herein,we have succeeded in developing a one-pot strategy to overcome the above-mentioned difficulties of g-C_(3)N_(4).The broadening of the visible-light response range and inducing magnetic nature to g-C_(3)N_(4) was succeeded by preparing a nanocomposite with Fe_(2)O_(3) via a facile solvothermal method.The preparation method additionally imparted layer exfoliation of g-C_(3)N_(4) as evident from the XRD patterns and TEM images.The strong interaction between the components is revealed from the XPS analysis.The broadened visible-light absorbance of Fe_(2)O_(3)/g-C_(3)N_(4) with a Z-scheme photocatalytic degradation mechanism is well evident from the UV-Vis DRS analysis and PL measurement of the composite with terephthalic acid.The active species of photocatalysis were further investigated using scavenging studies in methylene blue degradation that revealed hydroxyl radicals and holes as the major contributors to the activity of Fe_(2)O_(3)/g-C_(3)N_(4).展开更多
基金jointly supported by National Science Foundation of China (Grant Numbers: 11572271 and 51302236)the Principal Fund of Xiamen University (Hosted by Guanghui Yue, 2018)
文摘Rechargeable lithium–oxygen batteries have been considered as a promising energy storage technology because of their ultra-high theoretical energy densities which are comparable to gasoline. In order to improve the electrochemical properties of lithium–oxygen batteries(LOBs), especially the cycling performance, a high-efficiency cathode catalyst is the most important component.Hence, we aim to demonstrate that CuCr_2O_4@rGO(CCO@rGO) nanocomposites, which are synthesized using a facile hydrothermal method and followed by a series of calcination processes, are an effective cathode catalyst. The obtained CCO@rGO nanocomposites which served as the cathode catalyst of the LOBs exhibited an outstanding cycling performance for over 100 cycles with a fixed capacity of 1000 mAh g^(-1) at a current density of 200 mA g^(-1). The enhanced properties were attributed to the synergistic effect between the high catalytic efficiency of the spinel-structured CCO nanoparticles, the high specific surface area, and high conductivity of the rGO.
文摘通过共沉淀法合成了CuCr_(2)O_(4)黑色颜料。研究了沉淀剂(即尿素、氨水、氢氧化钠)对相组成和颜色性能的影响。同时,计算了以氨水和氢氧化钠为沉淀剂时CuCr_(2)O_(4)的结晶动力学和结晶机制。结果表明,由于两种离子(Cu^(2+)和Cr^(3+))的溶解度不同,沉淀过程的最佳pH值为7.5;由于产物中存在Cr2O3,尿素不适合作为沉淀剂。氨水作为沉淀剂时,CuCr_(2)O_(4)结晶的活化能为120.2 k J/mol,氢氧化钠作为沉淀剂时为141.3 k J/mol。CuCr_(2)O_(4)的结晶过程涉及成核和三维生长。较小的结晶活化能得到的CuCr_(2)O_(4)颗粒细小,分散均匀,呈色性能更优异。
基金supported by National Natural Science Foundation of China(No.51703015)Fundamental Research Funds for the Central Universities(No.2020CDJQY-A008).
文摘High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and ferromagnetic cobalt ferrite(CoFe_(2)O_(4))(0.00 wt%to 0.2 wt%)are prepared by a solution casting method accompanied by uniaxial stretching and high electric field poling.The decisive effect of the poling electric field on the power generating capability was confirmed by the experiments.For pure PVDF-HFP films,when the maximum electric field Emax is 120 MV/m,the calibrated open circuit voltage reaches 2.93 V,which is much higher than those poled at lower electric fields(70 MV/m:1.41 V;90 MV/m:2.11 V).Furthermore,the addition of CoFe_(2)O_(4)also influences the piezoelectricity dramatically.In the samples containing 0.15 wt%CoFe_(2)O_(4),the calibrated open circuit voltage increases to the maximum value of 3.57 V.Meanwhile,the relative fraction of theβ-phase and the crystallinity degree are 99%and 48%,respectively.The effects of CoFe_(2)O_(4)nanoparticles on initial crystallization,uniaxial stretching and high electric field poling are investigated by XRD,FTIR and DSC.
基金the support of Taif University Researchers Supporting Project Number TURSP-2020/12,Taif University,Taif,Saudi Arabia。
文摘The(1-x)NiCo_(2)O_(4)/x PbS(0≤x≤0.2)nanocomposite samples are synthesized using the hydrothermal and thermolysis procedures.The different phases developed in the obtained nanocomposite samples are accurately determined using the x-ray diffraction technique equipped with a line-detector.The percentage of the formed phases(NiCo_(2)O_(4)(NCO),PbS,PbSO_(4)),structural and microstructure parameters are determined using Rietveld quantitative phase analysis.The transmission electron microscope(TEM)images and Rietveld analysis reveal almost isotropic particle size in the nano range with a very narrow size distribution.The obtained phase percentage of PbS and PbSO4are smaller than nominated values(x)suggesting dissolving of some Pb and S ions into NCO which is then confirmed by the analysis of Fourier-transform infrared(FTIR)spectra of nanocomposite samples.The absorption spectra are modified upon doping NCO with PbS.The optical band gaps of the nanocomposites increase as the amount of PbS augments.The effect of alloying on extinction coefficient,refractive index,dielectric constant,optical conductivity,the intensity,and emitted color from the photoluminescence of the nanocomposite samples are also studied.The refractive index value of NCO and NCO-PbS nanocomposite samples exhibit normal dispersions.The photoluminescent measurements reveal that the NCO-PbS nanocomposites can emit a violet color.The improvement in the values of the nonlinear optical(NLO)parameters of pristine NCO at high frequencies or the nanocomposite samples at low frequencies,are made them used in NLO photonic devices.
基金supported by the Fundamental Research Funds for the Central Universities(DUT21LK34)Natural Science Foundation of Liaoning Province(2020-MS-113).
文摘Rational design of oxygen evolution reaction(OER)catalysts at low cost would greatly benefit the economy.Taking advantage of earth-abundant elements Si,Co and Ni,we produce a unique-structure where cobalt-nickel silicate hydroxide[Co_(2.5)Ni_(0.5)Si_(2)O_(5)(OH)_(4)]is vertically grown on a reduced graphene oxide(rGO)support(CNS@rGO).This is developed as a low-cost and prospective OER catalyst.Compared to cobalt or nickel silicate hydroxide@rGO(CS@rGO and NS@rGO,respectively)nanoarrays,the bimetal CNS@rGO nanoarray exhibits impressive OER performance with an overpotential of 307 mV@10 mA cm^(-2).This value is higher than that of CS@rGO and NS@rGO.The CNS@rGO nanoarray has an overpotential of 446 mV@100 mA cm^(-2),about 1.4 times that of the commercial RuO_(2)electrocatalyst.The achieved OER activity is superior to the state-of-the-art metal oxides/hydroxides and their derivatives.The vertically grown nanostructure and optimized metal-support electronic interactions play an indispensable role for OER performance improvement,including a fast electron transfer pathway,short proton/electron diffusion distance,more active metal centers,as well as optimized dualatomic electron density.Taking advantage of interlay chemical regulation and the in-situ growth method,the advanced-structural CNS@rGO nanoarrays provide a new horizon to the rational and flexible design of efficient and promising OER electrocatalysts.
基金supported by the National Natural Science Foundation of China(Nos.22274149,22074137,22274147 and 21721003)Jilin Province Science and Technology Development Plan Project(No.20210506012ZP)。
文摘The effective,stable,and secure catalysts are essential for sulfate radical(SO_(4)·−)-based advanced oxidation processes(SR-AOPs)to the degradation of organic contaminants in water.Heterogeneous supported cobalt-based catalysts are commonly used to activate peroxymonosulfate(PMS)to achieve the degradation.In this work,we synthesized Co_(3)O_(4)@Al_(2)O_(3)three-dimensional(3D)mesoporous nanocomposite(denoted as Co_(3)O_(4)@Al_(2)O_(33)DPNC)in just one step by calcining cheap and green deep eutectic solvent(DES)solution containing Co salt.Co_(3)O_(4)@Al_(2)O_(33)DPNC with the high specific surface area(93.246 m^(2)/g),uniform pore distribution(3.829 nm)and rich porosity(0.255 cm^(3)/g)were attained in a beautiful hierarchical structure which exhibited the open 3D propeller-like microstructure,two-dimensional lamellar substructure with rich folds,as well as the decoration of highly dispersed Co_(3)O_(4)nanoparticles on mesoporous amorphous Al_(2)O_(3).The excellent chemical and thermal stability of Al_(2)O_(3)ensures the high stability of the catalyst,and the formation of the complex hierarchical structure makes the active Co_(3)O_(4)be homogenously dispersed for effective catalysis.The catalyst demonstrated outstanding performance for catalytic degradations of organic pollutants(acetaminophen,oxytetracycline,5-sulfosalicylic acid,orange G and Rhodamine B)by generated SO_(4)·−,·OH and^(1)O_(2).With a very low cobalt content(equal to 28.2 mg/L of Co),the catalyst exhibited very high stability and excellent reusability in the recycling usages,while the leaching of the cobalt element(<0.145 mg/L)was also at a low level.Our catalyst achieved effective degradations of acetaminophen in cycles without losing its stable hierarchical nanostructure.
基金The authors are grateful for the supports from the National Natural Science Foundation of China(U21A2093 and 52203100)Y.L.Zhang would like to thank the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(CX2021107)。
文摘High-efficiency electromagnetic interference(EMI)shielding materials are of great importance for electronic equipment reliability,information security and human health.In this work,bidirectional aligned Ti_(3)C_(2)T_(x)@Fe_(3)O_(4)/CNF aerogels(BTFCA)were firstly assembled by bidirectional freezing and freeze-drying technique,and the BTFCA/epoxy nanocomposites with long-range aligned lamellar structures were then prepared by vacuum-assisted impregnation of epoxy resins.Benefitting from the successful construction of bidirectional aligned three-dimensional conductive networks and electromagnetic synergistic effect,when the mass fraction of Ti_(3)C_(2)T_(x) and Fe_(3)O_(4) are 2.96 and 1.48 wt%,BTFCA/epoxy nanocomposites show outstanding EMI shield-ing effectiveness of 79 dB,about 10 times of that of blended Ti_(3)C_(2)T_(x)@Fe_(3)O_(4)/epoxy(8 dB)nanocomposites with the same loadings of Ti_(3)C_(2)T_(x) and Fe_(3)O_(4).Meantime,the corresponding BTFCA/epoxy nanocomposites also present excellent thermal stability(T_(heat-resistance index) of 198.7℃)and mechanical properties(storage modulus of 9902.1 MPa,Young’s modulus of 4.51 GPa and hardness of 0.34 GPa).Our fabricated BTFCA/epoxy nanocomposites would greatly expand the applications of MXene and epoxy resins in the fields of information security,aerospace and weapon manufacturing,etc.
基金financially supported by the National Natural Science Foundation of China(Nos.U1706225,42006046,2019GGX102014,2019YFC0312103)the Research Fund of Open Studio for Marine Corrosion and Protection,Pilot National Laboratory for Marine Science and Technology(Qingdao,No.HYFSKF201804)。
文摘A Ag@CuFe_(2)O_(4)@TiO_(2) nanocomposite film with high performance of photogenerated cathodic protection was prepared by hydrothermal and photoreduction methods.The results showed that when the CuFe_(2)O_(4) hydrothermal reaction time was 6 h and the AgNO_(3) concentration was 0.1 M,the Ag@CuFe_(2)O_(4)@TiO_(2) nanocomposite material performed the best cathodic protection capability for 304 stainless steel(304SS).In this case,the protective potential achieved-930 mV(versus SCE)associated with the photocurrent density of 475μA/cm^(2),which was 14.8 times that of pure TiO_(2) nanowires.In the dark,the nanocomposite provided cathodic protection of up to 485 mV for 304SS.Due to the heterogeneous junctions at the two interfaces among the three kinds of nanocomposite materials,the build-in electric field was fabricated,which promoted the separation efficiency of photogenerated electrons and holes and effectively improved the photochemical cathodic protection of 304SS.
基金supported by the National Natural Science Foundation of China(Nos.21576028 and 21506012)the Opening Project of State Key Laboratory of Advanced Chemical Power Sources(No.SKL-ACPS-C-19)。
文摘The development of novel anode materials,with superior rate capability,is of utmost significance for the successful realization of sodium-ion batteries(SIBs).Herein,we present a nanocomposite of Nb_(2)O_(5)and reduced graphene oxide(rGO)by using hydrothermal-assisted microemulsion route.The water-in-oil microemulsion formed nanoreactors,which restrained the particle size of Nb_(2)O_(5)and shortened the diffusion length of ions.Moreover,the rGO network prevented agglomeration of Nb_(2)O_(5)nanoparticles and improved electronic conductivity.Consequently,Nb_(2)O_(5)@rGO nanocomposite is employed as anode material in SIBs,delivering a capacity of 195 mAh/g after 200 charge/discharge cycles at 0.2 A/g.Moreover,owing to conductive rGO network,the Nb_(2)O_(5)@rGO electrode rende red a specific capacity of 76 mAh/g at high current density of 10 A/g and maintained 98 mAh/g after 1000 charge/discharge cycles at 2 A/g.The Nb_(2)O_(5)@rGO electrode material prepared by microemulsion method shows promising possibilities for application of SIBs.
基金This work is supported by the U.S.Office of Naval Research(ONR,N00014-20-1-2600)The high-resolution TEM/STEM characterization at Purdue University is supported by the U.S.National Science Foundation(Nos.DMR-1565822 and DMR-2016453)。
文摘A new vertically aligned nanocomposite(VAN)structure based on two-dimensional(2D)layered oxides has been designed and self-assembled on both LaAlO_(3)(001)and SrTiO3(001)substrates.The new VAN structure consists of epitaxially grown Co_(3)O_(4) nanopillars embedded in the Bi_(2)WO_(6) matrix with a unique 2D layered structure,as evidenced by the microstructural analysis.Physical property measurements show that the new Bi_(2)WO_(6)-Co_(3)O_(4) VAN structure exhibits strong ferromagnetic and piezoelectric response at room temperature as well as anisotropic permittivity response.This work demonstrates a new approach in processing multifunctional VANs structure based on the layered oxide systems towards future nonlinear optics,ferromagnets,and multiferroics.
文摘The low surface area,high recombination rate of photogenerated charge carriers,narrow visible range activity,and difficulty in the separation from cleaned solutions limit the wide application of g-C_(3)N_(4) as a photocatalyst.Herein,we have succeeded in developing a one-pot strategy to overcome the above-mentioned difficulties of g-C_(3)N_(4).The broadening of the visible-light response range and inducing magnetic nature to g-C_(3)N_(4) was succeeded by preparing a nanocomposite with Fe_(2)O_(3) via a facile solvothermal method.The preparation method additionally imparted layer exfoliation of g-C_(3)N_(4) as evident from the XRD patterns and TEM images.The strong interaction between the components is revealed from the XPS analysis.The broadened visible-light absorbance of Fe_(2)O_(3)/g-C_(3)N_(4) with a Z-scheme photocatalytic degradation mechanism is well evident from the UV-Vis DRS analysis and PL measurement of the composite with terephthalic acid.The active species of photocatalysis were further investigated using scavenging studies in methylene blue degradation that revealed hydroxyl radicals and holes as the major contributors to the activity of Fe_(2)O_(3)/g-C_(3)N_(4).
