FeS2/Fe composites were mechanochemically prepared with iron powder and pyrite for the stabilization of ferrite arsenate sludge(FAS).The effects of preparation parameters on stabilization performance were investigated...FeS2/Fe composites were mechanochemically prepared with iron powder and pyrite for the stabilization of ferrite arsenate sludge(FAS).The effects of preparation parameters on stabilization performance were investigated.The results show that the optimum conditions are FeS2/Fe molar ratio of 5:5,milling time of 2 h,ball-to-material mass ratio of 15:1 and milling with stainless steel ball.Then,the composites were characterized by XRD,SEM,FTIR,etc.The physicochemical properties of FeS2/Fe mixture change dramatically,which is responsible for its excellent performance.Finally,the stabilization process of FAS was optimized.When the FAS is mixed with composites at mass ratio of 4:1 and milled for 30 min,the As leaching concentration of FAS can be reduced from 639.15 to 4.74 mg/L with the stabilization ratio of 99.2%.展开更多
采用铜模吸铸制备了厚度为0.8 mm,成分为Nd9Fe81-x-yTi4C2BxNby(x=11,13,15;y=0,4)的Nd2Fe14B/Fe3B型纳米复合永磁合金块体样品,研究了添加Nb对合金铸态组织及其晶化行为的影响,并测试了其磁性能。结果表明:在合金中添加4%(原子分数)Nb...采用铜模吸铸制备了厚度为0.8 mm,成分为Nd9Fe81-x-yTi4C2BxNby(x=11,13,15;y=0,4)的Nd2Fe14B/Fe3B型纳米复合永磁合金块体样品,研究了添加Nb对合金铸态组织及其晶化行为的影响,并测试了其磁性能。结果表明:在合金中添加4%(原子分数)Nb元素,不仅能抑制吸铸样品表面Nd2Fe23B3软磁性相、Nd1.1Fe4B4非磁性相和未知相的形成,导致Nd2Fe14B,Fe3B和α-Fe相的相对量增加,而且促使样品内部在非晶基体上形成了少量的Nd2Fe14B和α-Fe,Fe3B纳米晶。添加了Nb的合金吸铸样品表现出一定的硬磁性,其中Nd9Fe66Ti4C2B15Nb4吸铸样品具有最高的矫顽力(Hci=116.66 k A·m-1);添加4%(原子分数)Nb使得合金在晶化过程中由原来的异相同温一步晶化转变为两步晶化,且初始晶化温度Tx均明显降低,两个放热峰的ΔTpx均增大。展开更多
As environmentally benign and high-efficiency energy storage devices,sodium-ion capacitors(SICs),which combine the merits of batteries and supercapacitors,are considered to have potentially high energy/power densities...As environmentally benign and high-efficiency energy storage devices,sodium-ion capacitors(SICs),which combine the merits of batteries and supercapacitors,are considered to have potentially high energy/power densities and long lifespan.However,the lack of high-rate anodes that can match the high-power-density cathode hinders the commercial application of SICs.In this work,heterostructured Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite is pre-pared by chemical vapor deposition(CVD)method and investigated as the anode for SICs.Through heterointerface manipulation,Fe/FeSe_(2)/Fe_(3)Se_(4)demonstrates better sodium ion storage performances than the pure FeSe_(2)and FeSe_(2)/Fe_(3)Se_(4).It can deliver a specific capacity of 484.8 mAh·g^(-1)after 100 cycles at 0.5 A·g^(-1),as well as a good capacity retention.The excellent performance of Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite can be ascribed to the synergistic effect of the heterointerface engineered components,where FeSe_(2)and Fe_(3)Se_(4) are responsible for offering a high capacity and metallic Fe can server as mini-current collectors,effec-tively accelerating the electron and charge transfer behavior.Meanwhile,the heterointerface significantly facilitates the sodium ion fast transport,and retards the structural variation during cycling.FeSe-1000//activated carbon(AC)SIC affords a high energy density of 112 Wh·kg^(-1)at 107.5 W·kg^(-1),its power density can achieve 10,750 W·kg^(-1)with remained energy density of 44.2 Wh·kg^(-1),as well as an outstanding cycling stability,demonstrating this effective heterointerface engineered anode strategy for high-performance SICs.展开更多
The compound effect of Nd2Fe14B/Fe3B-Ferrite bonded magnets was studied.The result shows that the value ofβjHC obviously decreases with the ferrite content increasing.In addition, a functional relation between magnet...The compound effect of Nd2Fe14B/Fe3B-Ferrite bonded magnets was studied.The result shows that the value ofβjHC obviously decreases with the ferrite content increasing.In addition, a functional relation between magnetic properties and ferrite content was clearly revealed by the physical relation in the magnetic powders.展开更多
Electrocatalysts with high catalytic activity and stability play a key role in promising renewable energy technologies, such as fuel cells and metal-air batteries. Here, we report the synthesis of Fe/Fe203 nanoparticl...Electrocatalysts with high catalytic activity and stability play a key role in promising renewable energy technologies, such as fuel cells and metal-air batteries. Here, we report the synthesis of Fe/Fe203 nanoparticles anchored on Fe-N-doped carbon nanosheets （Fe/Fe2Og@Fe-N-C） using shrimp shell-derived N-doped carbon nanodots as carbon and nitrogen sources in the presence of FeCI3 by a simple pyrolysis approach. Fe/Fe203@Fe-N-C obtained at a pyrolysis temperature of 1,000 ℃ （Fe/Fe2OB@Fe-N-C-1000） possessed a mesoporous structure and high surface area of 747.3 m2-g-1. As an electrocatalyst, Fe/Fe203@Fe-N-C-1000 exhibited bifunctional electrocatalytic activities toward the oxygen reduction reaction （ORR） and oxygen evolution reaction （OER） in alkaline media, com- parable to that of commercial Pt/C for ORR and RuO2 for OER, respectively. The Zn-air battery test demonstrated that Fe/Fe2OB@Fe-N-C-1000 had a superior rechargeable performance and cycling stability as an air cathode material with an open drcuit voltage of 1.47 V （vs. Ag/AgCl） and a power density of 193 mW.cm-2 at a current density of 220 mA-cm-2. These performances were better than other commercial catalysts with an open circuit voltage of 1.36 V and a power density of 173 mW-cm^-2 at a current density of 220 mA.cm-2 （a mixture of commercial Pt/C and RuO2 with a mass ratio of 1：1 was used for the rechargeable Zn-air battery measurements）. This work will be helpful to design and develop low-cost and abundant bifunctional oxygen electrocatalysts for future metal-air batteries.展开更多
基金Projects(2018YFC1900305,2018YFC1903301)supported by the National Key R&D Program of ChinaProject(51825403)supported by the National Natural Science Foundation for Distinguished Young Scholars of China+1 种基金Project(51634010)supported by the National Natural Science Foundation of ChinaProject(2017RS3010)supported by the Science and Technology Program of Hunan Province,China
文摘FeS2/Fe composites were mechanochemically prepared with iron powder and pyrite for the stabilization of ferrite arsenate sludge(FAS).The effects of preparation parameters on stabilization performance were investigated.The results show that the optimum conditions are FeS2/Fe molar ratio of 5:5,milling time of 2 h,ball-to-material mass ratio of 15:1 and milling with stainless steel ball.Then,the composites were characterized by XRD,SEM,FTIR,etc.The physicochemical properties of FeS2/Fe mixture change dramatically,which is responsible for its excellent performance.Finally,the stabilization process of FAS was optimized.When the FAS is mixed with composites at mass ratio of 4:1 and milled for 30 min,the As leaching concentration of FAS can be reduced from 639.15 to 4.74 mg/L with the stabilization ratio of 99.2%.
文摘采用铜模吸铸制备了厚度为0.8 mm,成分为Nd9Fe81-x-yTi4C2BxNby(x=11,13,15;y=0,4)的Nd2Fe14B/Fe3B型纳米复合永磁合金块体样品,研究了添加Nb对合金铸态组织及其晶化行为的影响,并测试了其磁性能。结果表明:在合金中添加4%(原子分数)Nb元素,不仅能抑制吸铸样品表面Nd2Fe23B3软磁性相、Nd1.1Fe4B4非磁性相和未知相的形成,导致Nd2Fe14B,Fe3B和α-Fe相的相对量增加,而且促使样品内部在非晶基体上形成了少量的Nd2Fe14B和α-Fe,Fe3B纳米晶。添加了Nb的合金吸铸样品表现出一定的硬磁性,其中Nd9Fe66Ti4C2B15Nb4吸铸样品具有最高的矫顽力(Hci=116.66 k A·m-1);添加4%(原子分数)Nb使得合金在晶化过程中由原来的异相同温一步晶化转变为两步晶化,且初始晶化温度Tx均明显降低,两个放热峰的ΔTpx均增大。
基金financially supported by the Natural Science Foundation of Hebei Province of China(Nos.E2021202011 and E2018202123)Jian-Hua Research Foundation of Hebei University of Technology(No.HB1921)+4 种基金High-strength,Highprecision,Superconducting Rail Transit Aluminum Research and Development and Industrialization Projects(No.2019TSLH0110)"One Belt,One Road"Technology Innovation Cooperation Project of Tianjin(No.18PTZWHZ00220)Ministry of Science and Higher Education of the Russian Federation as part of World-class Research Center program(No.075-15-2020-934)Foundation of Strengthening Program(No.2019-JCJQ-142-00)the Exchange Project of the Third Meeting of the Science and Technology Cooperation Subcommittee of the China-Ukraine Intergovernmental Cooperation Committee(No.CU03-11).
文摘As environmentally benign and high-efficiency energy storage devices,sodium-ion capacitors(SICs),which combine the merits of batteries and supercapacitors,are considered to have potentially high energy/power densities and long lifespan.However,the lack of high-rate anodes that can match the high-power-density cathode hinders the commercial application of SICs.In this work,heterostructured Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite is pre-pared by chemical vapor deposition(CVD)method and investigated as the anode for SICs.Through heterointerface manipulation,Fe/FeSe_(2)/Fe_(3)Se_(4)demonstrates better sodium ion storage performances than the pure FeSe_(2)and FeSe_(2)/Fe_(3)Se_(4).It can deliver a specific capacity of 484.8 mAh·g^(-1)after 100 cycles at 0.5 A·g^(-1),as well as a good capacity retention.The excellent performance of Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite can be ascribed to the synergistic effect of the heterointerface engineered components,where FeSe_(2)and Fe_(3)Se_(4) are responsible for offering a high capacity and metallic Fe can server as mini-current collectors,effec-tively accelerating the electron and charge transfer behavior.Meanwhile,the heterointerface significantly facilitates the sodium ion fast transport,and retards the structural variation during cycling.FeSe-1000//activated carbon(AC)SIC affords a high energy density of 112 Wh·kg^(-1)at 107.5 W·kg^(-1),its power density can achieve 10,750 W·kg^(-1)with remained energy density of 44.2 Wh·kg^(-1),as well as an outstanding cycling stability,demonstrating this effective heterointerface engineered anode strategy for high-performance SICs.
文摘The compound effect of Nd2Fe14B/Fe3B-Ferrite bonded magnets was studied.The result shows that the value ofβjHC obviously decreases with the ferrite content increasing.In addition, a functional relation between magnetic properties and ferrite content was clearly revealed by the physical relation in the magnetic powders.
基金This work was financially supported by the National Natural Science Foundation of China （Nos. 51372248 and 51432009）, the Instrument Developing Project of the Chinese Academy of Sciences （No. yz201421） and the CAS/SAFEA International Partnership Program for Creative Research Teams of Chinese Academy of Sciences, the CAS Pioneer Hundred Talents Program and the Users with Potential Program （No. 2015HSC- UP006, Hefei Science Center, CAS）, China.
文摘Electrocatalysts with high catalytic activity and stability play a key role in promising renewable energy technologies, such as fuel cells and metal-air batteries. Here, we report the synthesis of Fe/Fe203 nanoparticles anchored on Fe-N-doped carbon nanosheets （Fe/Fe2Og@Fe-N-C） using shrimp shell-derived N-doped carbon nanodots as carbon and nitrogen sources in the presence of FeCI3 by a simple pyrolysis approach. Fe/Fe203@Fe-N-C obtained at a pyrolysis temperature of 1,000 ℃ （Fe/Fe2OB@Fe-N-C-1000） possessed a mesoporous structure and high surface area of 747.3 m2-g-1. As an electrocatalyst, Fe/Fe203@Fe-N-C-1000 exhibited bifunctional electrocatalytic activities toward the oxygen reduction reaction （ORR） and oxygen evolution reaction （OER） in alkaline media, com- parable to that of commercial Pt/C for ORR and RuO2 for OER, respectively. The Zn-air battery test demonstrated that Fe/Fe2OB@Fe-N-C-1000 had a superior rechargeable performance and cycling stability as an air cathode material with an open drcuit voltage of 1.47 V （vs. Ag/AgCl） and a power density of 193 mW.cm-2 at a current density of 220 mA-cm-2. These performances were better than other commercial catalysts with an open circuit voltage of 1.36 V and a power density of 173 mW-cm^-2 at a current density of 220 mA.cm-2 （a mixture of commercial Pt/C and RuO2 with a mass ratio of 1：1 was used for the rechargeable Zn-air battery measurements）. This work will be helpful to design and develop low-cost and abundant bifunctional oxygen electrocatalysts for future metal-air batteries.
