Coral-like structures of the Y_(3-x)Pr_(x)Fe_(5-y)Yb_(y)O_(12),(0.00 ≤ x ≤ 0.04, 0.00 ≤ y ≤ 0.02) compound were synthesized using the sol-gel method. Structural investigation certified the YIG cubic crystal struct...Coral-like structures of the Y_(3-x)Pr_(x)Fe_(5-y)Yb_(y)O_(12),(0.00 ≤ x ≤ 0.04, 0.00 ≤ y ≤ 0.02) compound were synthesized using the sol-gel method. Structural investigation certified the YIG cubic crystal structure formation, without any secondary phase. It is shown that, the relatively large ionic radius of the dopant cations results in an expansion of the lattice parameter, variations in the Iona-O-Iondangle, Iona-O,Iond-O and Ionc-O bond distances and decrease in the average crystallite size. Fourier transform infrared(FTIR) and Raman measurements are essential to testify the single-phase formation of YIG crystal structure and are observed changes in the stretching and vibrational modes, respectively. The morphological study, energy dispersive spectroscopy(EDS) spectra and textural properties show corallike structures, peaks associated with Pr^(3+) and Yb^(3+) atoms and the effect of dopants on surface area,diameter, and pore volume, respectively. The optical analysis from diffuse reflectance spectra witnessed an increase in the optical gap band, a decrease in Urbach energy and blue shift in the charge transfer,correlated with the expansion of the unit cell due to the dopant's insertion in the YIG structure. A typical ferrimagnetic behavior is exhibited by the Y_(3-x)Pr_(x)Fe_(5-y)Yb_(y)O_(12)compound. The saturation magnetization(M_(s)), cubic anisotropy constant(K_(1)) and coercive field(H_(c)) increase with the Pr^(3+)cations content, as consequence of their magnetic nature and distribution around of Fe^(3+)ions due to the coexistence with the Yb^(3+). Finally, for the first time, antibacterial tests by mean of the direct contact method were performed for YIG co-doped with Pr^(3+)and Yb^(3+)and it is shown that, relatively high dosages of Pr^(3+) cations favored the activity against S. aureus, therefore, a new biological property for YIG doped with rare earths is presented.展开更多
This paper investigates the generation of self-organized surface structures on amorphous alloys by vortex femtosecond laser pulses. The scanning electron microscope characterizations show that the as-formed structures...This paper investigates the generation of self-organized surface structures on amorphous alloys by vortex femtosecond laser pulses. The scanning electron microscope characterizations show that the as-formed structures are periodic ripples, aperiodic ripples, and ‘coral-like＇ structures. Optimal conditions for forming these surface structures are determined in terms of pulses number at a given pulse energy. The applicable mechanism is suggested to interpret the formation and evolution of the ＇coral-like＇ structures.展开更多
Coral reef-like Ni/Al2O3 catalysts were prepared by co-precipitation of nickel acetate and aluminium nitrate with sodium carbonate aqueous solution in the medium of ethylene glycolye.Methanation of syngas was carried ...Coral reef-like Ni/Al2O3 catalysts were prepared by co-precipitation of nickel acetate and aluminium nitrate with sodium carbonate aqueous solution in the medium of ethylene glycolye.Methanation of syngas was carried out over coral reef-like Ni/Al2O3 catalysts in a continuous flow type fixed-bed reactor.The structure and properties of the fresh and used catalysts were studied by SEM,N2 adsorption-desorption,XRD,H2-TPR,O2-TPO,TG and ICP-AES techniques.The results showed that the coral reef-like Ni/Al2O3 catalysts exhibited better activity than the conventional Ni/Al2O3-H2O catalysts.The activities of coral reef-like catalysts were in the order of Ni/Al2O3-673Ni/Al2O3-573Ni/Al2O3- 473Ni/Al2O3-773.Ni/Al2O3-673-EG catalyst showed not only good activity and improved stability but also superior resistance to carbon deposition,sintering,and Ni loss.Under the reaction conditions of CO/H2（molar ratio）=1：3,593 K,atmospheric pressure and a GHSV of 2500 h-1,CH4 selectivity was 84.7%,and the CO conversion reached 98.2%.展开更多
Novel hierarchical coral-like Ni-Mo sulfides on Ti mesh （denoted as HC-NiMoSfri） were synthesized through facile hydrothermal and subsequent sulfuration processes without any template. These non-precious HC-NiMoS/Ti...Novel hierarchical coral-like Ni-Mo sulfides on Ti mesh （denoted as HC-NiMoSfri） were synthesized through facile hydrothermal and subsequent sulfuration processes without any template. These non-precious HC-NiMoS/Ti hybrids were explored as bifunctional catalysts for urea-based overall water splitting, including the anodic urea oxygen evolution reaction （UOR） and cathodic hydrogen evolution reaction （HER）. Due to the highly exposed active sites, excellent charge transfer ability, and good synergistic effects from multi-component reactions, the HC-NiMoS/Ti hybrid exhibited superior activity and high stability, and only a cell voltage of 1.59 V was required to deliver 10 mA.cm-2 current density in an electrolyte of 1.0 M KOH with 0.5 M urea.展开更多
As one of the most promising next-generation energy storage devices,the lithium-metal battery has been extensively investigated.However,safety issues and undesired lithium dendrite growth hinder its development.The ap...As one of the most promising next-generation energy storage devices,the lithium-metal battery has been extensively investigated.However,safety issues and undesired lithium dendrite growth hinder its development.The application of solid-state electrolytes has attracted increasing attention as they can solve safety issues and show great potential to inhibit the growth of lithium dendrites.Polyethylene oxide(PEO)-based electrolytes are very promising due to their enhanced safety and excellent flexibility.However,they suffer from low ionic conductivity at room temperature and cannot effectively inhibit lithium dendrites at high temperatures due to the intrinsic semicrystalline properties and poor mechanical strength.In this work,a novel coral-like Li_(6.25)Al_(0.25)La_(3)Zr_(2)O_(12)(C-LALZO)is synthesized to serve as an active ceramic filler in PEO.The PEO with LALZO coral(PLC)exhibits increased ionic conductivity and mechanical strength,which leads to uniform deposition/stripping of lithium metal.The Li symmetric cells with PLC do not cause a short circuit after cycling for 1500 h at 60℃.The assembled LiFePO_(4)/PLC/Li batteries display excellent cycling stability at both 60 and 50℃.This work reveals that the electrochemical properties of the composite electrolyte can be effectively improved by tuning the microstructure of the filler,such as the C-LALZO architecture.展开更多
Molybdenum phosphide(MoP) has attracted extensive attention as promising anode candidates for lithium-ion batteries owing to its high specific capacity,low potential range and low polarization.However,severe volume ch...Molybdenum phosphide(MoP) has attracted extensive attention as promising anode candidates for lithium-ion batteries owing to its high specific capacity,low potential range and low polarization.However,severe volume changes and intrinsic low conductivity are major challenges for further application of MoP electrode materials.In this work,a coral-like MoP microsphere encapsulated by N-doped carbon(MoP@NDC) was successfully prepared through annealing the precursor derived from self-polymerization of dopamine with phosphomolybdic acid.The introduction of carbon framework not only serves as matrix to confine MoP nanocrystals from aggregations,but also improves the electrochemical conductivity and facilitates lithium ion or electron transport on the surface of MoP.Such hierarchical structure delivered high discharge capacity of 495 mAh g^(-1) after 300 cycles with 90.1 % capacity retention,which could be attributed to the synergistic effects of MoP nanoparticles and conductive carbon network.This design strategy shows MoP@NDC electrode with applicable application as anode in lithium-ion battery.展开更多
Metal-organic frameworks(MOFs)are considered as a novel type of microwave absorption(MA)material owing to the sufficient pore structure,diverse configurations,and easy-to-control magnetic properties.However,their evol...Metal-organic frameworks(MOFs)are considered as a novel type of microwave absorption(MA)material owing to the sufficient pore structure,diverse configurations,and easy-to-control magnetic properties.However,their evolution is limited by the imperfect impedance matching conditions caused by the undesirable microstructure.Herein,two types of novel porous coral-like carbon/Co_(3)O_(4)and carbon/Co composites have been effectively fabricated for the first time by a facile heat treatment process of precursor Co-MOF-71.The graphitization degree,magnetic property and MA ability of the product can be effortlessly tuned by altering the heat treatment temperature of Co-MOF-71.Remarkably,S500(Co-MOF-71 calcined at 500℃)composite displays strong and multi-frequency absorption performance,whose minimum reflection loss(RL)value achieves-36.4 d B with an absorbing thickness of 3.0 mm and attains an effective absorbing bandwidth(RL≤-10 dB)of 5.76 GHz(almost covers whole Ku band)at a thinner coating thickness of 2.5 mm.Such superb MA ability has roots in the coral-like structure derived from the layer Co-MOF-71,sufficient electromagnetic loss.This work ameliorates the MA ability of MOFs through a special nanostructural design,which provides a fresh way for the preparation of novel MA materials.展开更多
The morphologies evolution of various types of inclusions in Ti-IF steel were observed by a special depth erosion method,and the formation and evolution process were discussed.The results showed that the main inclusio...The morphologies evolution of various types of inclusions in Ti-IF steel were observed by a special depth erosion method,and the formation and evolution process were discussed.The results showed that the main inclusions were FeO·xMnO before Al deoxidization and the ratio of integrated oxygen and free oxygen was in ranged of 0.3 to 0.4.In present study,the main effect factors on the morphologies of Al_2O_3 inclusions were [Al]/[O]_(Free)(soluble aluminum divide free oxygen) and initial free oxygen;cluster Al_2O_3 was formed easily with high free oxygen([O]_(Free)) and low[Al]/[O](blew 3 in present study).Otherwise,the dendritic Al_2O_3 was formed;coral-like Al_2O_3 was the mixture of the dendrite Al_2O_3 and spherical Al_2O_3.Some Al_2O_3·TiO_x inclusions appeared because a high[Ti]concentration region existed around 70TiFe(containing 70 percent titanium) particles after 70TiFe addition.The maximum sizes of Al_2O_3 reached 800μm when 3 min aluminum was added;as the time past,the large size Al_2O_3 decreased significantly;the maximum size of Al_2O_3 was blew 100μm and 50μm in calming sample and tundish sample respectively.展开更多
基金The authors are grateful to the Brazilian Agencies:Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior(CAPES),Conselho Nacional de Desenvolvimento Cientifico e Tecnologico(CNPq),(CNPq N 4/2021-Bolsa de Produtividade em Pesquisa-PQ 307659/2021-6),(Chamada CNPq/MCTI/FNDCT N°18/2021-Faixa A,407796/2021-5)Financiadora de Estudos e Projetos(FINEP)and Fundacao de Amparo a Ciencia e Tecnologia de Pernambuco(FACEPE)(APQ-0635-3.03/21-Jovens Pesquisadores).
文摘Coral-like structures of the Y_(3-x)Pr_(x)Fe_(5-y)Yb_(y)O_(12),(0.00 ≤ x ≤ 0.04, 0.00 ≤ y ≤ 0.02) compound were synthesized using the sol-gel method. Structural investigation certified the YIG cubic crystal structure formation, without any secondary phase. It is shown that, the relatively large ionic radius of the dopant cations results in an expansion of the lattice parameter, variations in the Iona-O-Iondangle, Iona-O,Iond-O and Ionc-O bond distances and decrease in the average crystallite size. Fourier transform infrared(FTIR) and Raman measurements are essential to testify the single-phase formation of YIG crystal structure and are observed changes in the stretching and vibrational modes, respectively. The morphological study, energy dispersive spectroscopy(EDS) spectra and textural properties show corallike structures, peaks associated with Pr^(3+) and Yb^(3+) atoms and the effect of dopants on surface area,diameter, and pore volume, respectively. The optical analysis from diffuse reflectance spectra witnessed an increase in the optical gap band, a decrease in Urbach energy and blue shift in the charge transfer,correlated with the expansion of the unit cell due to the dopant's insertion in the YIG structure. A typical ferrimagnetic behavior is exhibited by the Y_(3-x)Pr_(x)Fe_(5-y)Yb_(y)O_(12)compound. The saturation magnetization(M_(s)), cubic anisotropy constant(K_(1)) and coercive field(H_(c)) increase with the Pr^(3+)cations content, as consequence of their magnetic nature and distribution around of Fe^(3+)ions due to the coexistence with the Yb^(3+). Finally, for the first time, antibacterial tests by mean of the direct contact method were performed for YIG co-doped with Pr^(3+)and Yb^(3+)and it is shown that, relatively high dosages of Pr^(3+) cations favored the activity against S. aureus, therefore, a new biological property for YIG doped with rare earths is presented.
基金Project supported by the Science and Technology Key Program of Shandong Province,China (Grant No. 2008GG10004020)China Postdoctoral Science Foundation (Grant No. AUGA41001348)+1 种基金Heilongjiang Province Postdoctoral Science Foundation(Grant No. AUGA1100074)the Program of Excellent Team in the Harbin Institute of Technology,China
文摘This paper investigates the generation of self-organized surface structures on amorphous alloys by vortex femtosecond laser pulses. The scanning electron microscope characterizations show that the as-formed structures are periodic ripples, aperiodic ripples, and ‘coral-like＇ structures. Optimal conditions for forming these surface structures are determined in terms of pulses number at a given pulse energy. The applicable mechanism is suggested to interpret the formation and evolution of the ＇coral-like＇ structures.
基金financially supported by Independent Research Subject from Ministry of Science and Technology of China(No.2008BWZ005)
文摘Coral reef-like Ni/Al2O3 catalysts were prepared by co-precipitation of nickel acetate and aluminium nitrate with sodium carbonate aqueous solution in the medium of ethylene glycolye.Methanation of syngas was carried out over coral reef-like Ni/Al2O3 catalysts in a continuous flow type fixed-bed reactor.The structure and properties of the fresh and used catalysts were studied by SEM,N2 adsorption-desorption,XRD,H2-TPR,O2-TPO,TG and ICP-AES techniques.The results showed that the coral reef-like Ni/Al2O3 catalysts exhibited better activity than the conventional Ni/Al2O3-H2O catalysts.The activities of coral reef-like catalysts were in the order of Ni/Al2O3-673Ni/Al2O3-573Ni/Al2O3- 473Ni/Al2O3-773.Ni/Al2O3-673-EG catalyst showed not only good activity and improved stability but also superior resistance to carbon deposition,sintering,and Ni loss.Under the reaction conditions of CO/H2（molar ratio）=1：3,593 K,atmospheric pressure and a GHSV of 2500 h-1,CH4 selectivity was 84.7%,and the CO conversion reached 98.2%.
文摘Novel hierarchical coral-like Ni-Mo sulfides on Ti mesh （denoted as HC-NiMoSfri） were synthesized through facile hydrothermal and subsequent sulfuration processes without any template. These non-precious HC-NiMoS/Ti hybrids were explored as bifunctional catalysts for urea-based overall water splitting, including the anodic urea oxygen evolution reaction （UOR） and cathodic hydrogen evolution reaction （HER）. Due to the highly exposed active sites, excellent charge transfer ability, and good synergistic effects from multi-component reactions, the HC-NiMoS/Ti hybrid exhibited superior activity and high stability, and only a cell voltage of 1.59 V was required to deliver 10 mA.cm-2 current density in an electrolyte of 1.0 M KOH with 0.5 M urea.
基金supported by the School Research Startup Expenses of Harbin Institute of Technology(Shenzhen)(DD29100027)the National Natural Science Foundation of China(52002094)+2 种基金China Postdoctoral Science Foundation(2019M661276)Guangdong Basic and AppliedBasic Research Foundation(2019A1515110756)the High-level Talents Discipline Construction Fund of Shandong University(31370089963078)。
文摘As one of the most promising next-generation energy storage devices,the lithium-metal battery has been extensively investigated.However,safety issues and undesired lithium dendrite growth hinder its development.The application of solid-state electrolytes has attracted increasing attention as they can solve safety issues and show great potential to inhibit the growth of lithium dendrites.Polyethylene oxide(PEO)-based electrolytes are very promising due to their enhanced safety and excellent flexibility.However,they suffer from low ionic conductivity at room temperature and cannot effectively inhibit lithium dendrites at high temperatures due to the intrinsic semicrystalline properties and poor mechanical strength.In this work,a novel coral-like Li_(6.25)Al_(0.25)La_(3)Zr_(2)O_(12)(C-LALZO)is synthesized to serve as an active ceramic filler in PEO.The PEO with LALZO coral(PLC)exhibits increased ionic conductivity and mechanical strength,which leads to uniform deposition/stripping of lithium metal.The Li symmetric cells with PLC do not cause a short circuit after cycling for 1500 h at 60℃.The assembled LiFePO_(4)/PLC/Li batteries display excellent cycling stability at both 60 and 50℃.This work reveals that the electrochemical properties of the composite electrolyte can be effectively improved by tuning the microstructure of the filler,such as the C-LALZO architecture.
基金supported by the Natural Science Foundation of Guangdong Province of China(No.2018A030313516)the Science and Technology Planning Project of Guangzhou(No.201804010449)。
文摘Molybdenum phosphide(MoP) has attracted extensive attention as promising anode candidates for lithium-ion batteries owing to its high specific capacity,low potential range and low polarization.However,severe volume changes and intrinsic low conductivity are major challenges for further application of MoP electrode materials.In this work,a coral-like MoP microsphere encapsulated by N-doped carbon(MoP@NDC) was successfully prepared through annealing the precursor derived from self-polymerization of dopamine with phosphomolybdic acid.The introduction of carbon framework not only serves as matrix to confine MoP nanocrystals from aggregations,but also improves the electrochemical conductivity and facilitates lithium ion or electron transport on the surface of MoP.Such hierarchical structure delivered high discharge capacity of 495 mAh g^(-1) after 300 cycles with 90.1 % capacity retention,which could be attributed to the synergistic effects of MoP nanoparticles and conductive carbon network.This design strategy shows MoP@NDC electrode with applicable application as anode in lithium-ion battery.
基金the financial support from the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Metal-organic frameworks(MOFs)are considered as a novel type of microwave absorption(MA)material owing to the sufficient pore structure,diverse configurations,and easy-to-control magnetic properties.However,their evolution is limited by the imperfect impedance matching conditions caused by the undesirable microstructure.Herein,two types of novel porous coral-like carbon/Co_(3)O_(4)and carbon/Co composites have been effectively fabricated for the first time by a facile heat treatment process of precursor Co-MOF-71.The graphitization degree,magnetic property and MA ability of the product can be effortlessly tuned by altering the heat treatment temperature of Co-MOF-71.Remarkably,S500(Co-MOF-71 calcined at 500℃)composite displays strong and multi-frequency absorption performance,whose minimum reflection loss(RL)value achieves-36.4 d B with an absorbing thickness of 3.0 mm and attains an effective absorbing bandwidth(RL≤-10 dB)of 5.76 GHz(almost covers whole Ku band)at a thinner coating thickness of 2.5 mm.Such superb MA ability has roots in the coral-like structure derived from the layer Co-MOF-71,sufficient electromagnetic loss.This work ameliorates the MA ability of MOFs through a special nanostructural design,which provides a fresh way for the preparation of novel MA materials.
文摘The morphologies evolution of various types of inclusions in Ti-IF steel were observed by a special depth erosion method,and the formation and evolution process were discussed.The results showed that the main inclusions were FeO·xMnO before Al deoxidization and the ratio of integrated oxygen and free oxygen was in ranged of 0.3 to 0.4.In present study,the main effect factors on the morphologies of Al_2O_3 inclusions were [Al]/[O]_(Free)(soluble aluminum divide free oxygen) and initial free oxygen;cluster Al_2O_3 was formed easily with high free oxygen([O]_(Free)) and low[Al]/[O](blew 3 in present study).Otherwise,the dendritic Al_2O_3 was formed;coral-like Al_2O_3 was the mixture of the dendrite Al_2O_3 and spherical Al_2O_3.Some Al_2O_3·TiO_x inclusions appeared because a high[Ti]concentration region existed around 70TiFe(containing 70 percent titanium) particles after 70TiFe addition.The maximum sizes of Al_2O_3 reached 800μm when 3 min aluminum was added;as the time past,the large size Al_2O_3 decreased significantly;the maximum size of Al_2O_3 was blew 100μm and 50μm in calming sample and tundish sample respectively.
