The microstructural evolution of a Mg, Ag and Zn micro-alloyed Al?3.8Cu?1.28Li (mass fraction, %) alloy ingot during two-step homogenization was examined in detail by optical microscopy (OM), differential scanning cal...The microstructural evolution of a Mg, Ag and Zn micro-alloyed Al?3.8Cu?1.28Li (mass fraction, %) alloy ingot during two-step homogenization was examined in detail by optical microscopy (OM), differential scanning calorimetry (DSC), electron probe micro-analysis (EPMA) and X-ray diffraction (XRD) methods. The results show that severe dendritic segregation exists in the as-cast ingot. There are many secondary phases, includingTB(Al7Cu4Li),θ(Al2Cu),R(Al5CuLi3) andS(Al2CuMg) phases, and a small amount of (Mg+Ag+Zn)-containing and AlCuFeMn phases. The fractions of intermetallic phases decrease sharply after 2 h of second-step homogenization. By prolonging the second-step homogenization time, theTB,θ,R,S and (Mg+Ag+Zn)-containing phases completely dissolve into the matrix. The dendritic segregation is eliminated, and the homogenization kinetics can be described by a constitutive equation in exponential function. However, it seems that the AlCuFeMn phase is separated into Al7Cu2Fe and AlCuMn phases, and the size of Al7Cu2Fe phase exhibits nearly no change when the second-step homogenization time is longer than 2 h.展开更多
用固相反应合成法合成了光催化剂Fe2BiTaO7,通过XRD、SEM、TEM、紫外-可见漫反射等表征方法对其组织结构及光催化性能进行了研究。结果表明Fe2BiTaO7为立方晶系烧绿石结构,空间群为Fd3m,禁带宽度为1.72 e V。通过比较Fe2BiTaO7、P25TiO...用固相反应合成法合成了光催化剂Fe2BiTaO7,通过XRD、SEM、TEM、紫外-可见漫反射等表征方法对其组织结构及光催化性能进行了研究。结果表明Fe2BiTaO7为立方晶系烧绿石结构,空间群为Fd3m,禁带宽度为1.72 e V。通过比较Fe2BiTaO7、P25TiO2、掺氮Ti O2和Bi2In Ta O7的可见光光催化降解罗丹明B,发现Fe2BiTaO7降解效果及催化活性均高于其它催化剂,并且Fe2BiTaO7降解罗丹明B效率是掺氮二氧化钛的1.5倍。Fe2BiTaO7降解罗丹明B的曲线符合一级动力学,一级动力学常数为0.022 93 min-1。研究了罗丹明B可能的降解路径和Fe2BiTaO7在可见光下降解苯酚的效果。Fe2BiTaO7(可见光)光催化剂系统适用于纺织工业废水处理。展开更多
以磷铁废渣(Fe1.5P)和温室效应气体CO_2为原料,以磷酸为补充磷源合成磷酸铁锂(LiFePO_4)的前驱体Fe_2P_2O_7,并研究了其合成过程对LiFePO_4正极材料储能性能的影响。采用SEM观察了LiFePO_4的表面形貌,采用XRD分析了LiFePO_4和Fe_2P_2O_...以磷铁废渣(Fe1.5P)和温室效应气体CO_2为原料,以磷酸为补充磷源合成磷酸铁锂(LiFePO_4)的前驱体Fe_2P_2O_7,并研究了其合成过程对LiFePO_4正极材料储能性能的影响。采用SEM观察了LiFePO_4的表面形貌,采用XRD分析了LiFePO_4和Fe_2P_2O_7的晶体结构。进一步对该方法进行优化,发现Fe1.5P与磷酸混合物(nFe1.5P∶nH3PO4=1∶1)在800℃热处理6 h合成的Fe_2P_2O_7对应的LiFePO_4/C电化学性能最好,在0.1C,0.2C,0.5C和1C倍率下的容量分别可达130,126,117和108 m Ah·g^(-1)。展开更多
利用Fe_2P_2O_7和碳酸锂为原材料,并通过不同的碳包覆合成LiFePO_4/C复合材料.利用XRD、SEM、碳硫分析仪、恒流充放电法和循环伏安对产物的组成、结构、形貌和电化学性能进行测试,确定含碳量为2.45wt%的LiFePO_4/C复合材料具有更好的电...利用Fe_2P_2O_7和碳酸锂为原材料,并通过不同的碳包覆合成LiFePO_4/C复合材料.利用XRD、SEM、碳硫分析仪、恒流充放电法和循环伏安对产物的组成、结构、形貌和电化学性能进行测试,确定含碳量为2.45wt%的LiFePO_4/C复合材料具有更好的电化学性能.实验结果表明,在0.1C倍率下,锂离子电池的放电比容量为130.49 m Ah/g,在1C倍率下,锂离子电池的放电比容量为108.58 m Ah/g.展开更多
Development of active iron based water oxidation for designing an ideal artificial photosynthesis devices operating under benign neutral pH is highly demanded. We investigated the electrocatalytic activity of Ruddlesd...Development of active iron based water oxidation for designing an ideal artificial photosynthesis devices operating under benign neutral pH is highly demanded. We investigated the electrocatalytic activity of Ruddlesden-Pop-per-type strontium ferrite (Sr3Fe2O7) toward the oxygen evolution reaction (OER). Owing to the temperature-dependent efficiency of the charge disproportionation of Fe4+, the OER activity of Sr3Fe2O7 varied with the temperature, and the onset potential for the OER at a neutral pH underwent a negative shift of approximately 200 mV by increasing the temperature for the stabilization of Fe4+. When metal substitution was made to Sr3Fe2O7 for stabilizing Fe4+ at room temperature, the temperature dependence of the OER activity disappeared and the OER was driven at a small overpotential without increasing the temperature, indicating that the stabilization of Fe4+ is substantially important for achieving high OER activity.展开更多
In order to obtain a new precursor for LiFePO4, Fe2P2O7 with high purity was prepared through solid phase reaction at 650 ℃ using starting materials of FeC2O4 and NH4H2PO4 in an argon atmosphere. Using the as-prepare...In order to obtain a new precursor for LiFePO4, Fe2P2O7 with high purity was prepared through solid phase reaction at 650 ℃ using starting materials of FeC2O4 and NH4H2PO4 in an argon atmosphere. Using the as-prepared Fe2P2O7, Li2CO3 and glucose as raw materials, pure LiFePO4 and LiFePO4/C composite materials were respectively synthesized by solid state reaction at 700 ℃ in an argon atmosphere. X-ray diffractometry and scanning electron microscopy（SEM） were employed to characterize the as-prepared Fe2P2O7, LiFePO4 and LiFePO4/C. The as-prepared Fe2P2O7 crystallizes in the Cl space group and belongs to β-Fe2P2O7 for crystal phase. The particle size distribution of Fe2P2O7 observed by SEM is 0.4-3.0 μm. During the Li^＋ ion chemical intercalation, radical P2O7^4- is disrupted into two PO4^3- ions in the presence of O^2-, thus providing a feasible technique to dispose this poor dissolvable pyrophosphate. LiFePO4/C composite exhibits initial charge and discharge capacities of 154 and 132 mA·h/g, respectively.展开更多
基金Project(ZR2021QE136)supported by the Natural Science Foundation of Shandong Province,ChinaProject(2020B010186002)supported by the Key Research and Development Program of Guangdong Province,China。
基金Project(2013JSJJ0001)supported by Teachers’Research Found,ChinaProject(2013AA032401)supported by the National High Technology Research and Development Program of ChinaProject supported by the Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center,China
文摘The microstructural evolution of a Mg, Ag and Zn micro-alloyed Al?3.8Cu?1.28Li (mass fraction, %) alloy ingot during two-step homogenization was examined in detail by optical microscopy (OM), differential scanning calorimetry (DSC), electron probe micro-analysis (EPMA) and X-ray diffraction (XRD) methods. The results show that severe dendritic segregation exists in the as-cast ingot. There are many secondary phases, includingTB(Al7Cu4Li),θ(Al2Cu),R(Al5CuLi3) andS(Al2CuMg) phases, and a small amount of (Mg+Ag+Zn)-containing and AlCuFeMn phases. The fractions of intermetallic phases decrease sharply after 2 h of second-step homogenization. By prolonging the second-step homogenization time, theTB,θ,R,S and (Mg+Ag+Zn)-containing phases completely dissolve into the matrix. The dendritic segregation is eliminated, and the homogenization kinetics can be described by a constitutive equation in exponential function. However, it seems that the AlCuFeMn phase is separated into Al7Cu2Fe and AlCuMn phases, and the size of Al7Cu2Fe phase exhibits nearly no change when the second-step homogenization time is longer than 2 h.
文摘用固相反应合成法合成了光催化剂Fe2BiTaO7,通过XRD、SEM、TEM、紫外-可见漫反射等表征方法对其组织结构及光催化性能进行了研究。结果表明Fe2BiTaO7为立方晶系烧绿石结构,空间群为Fd3m,禁带宽度为1.72 e V。通过比较Fe2BiTaO7、P25TiO2、掺氮Ti O2和Bi2In Ta O7的可见光光催化降解罗丹明B,发现Fe2BiTaO7降解效果及催化活性均高于其它催化剂,并且Fe2BiTaO7降解罗丹明B效率是掺氮二氧化钛的1.5倍。Fe2BiTaO7降解罗丹明B的曲线符合一级动力学,一级动力学常数为0.022 93 min-1。研究了罗丹明B可能的降解路径和Fe2BiTaO7在可见光下降解苯酚的效果。Fe2BiTaO7(可见光)光催化剂系统适用于纺织工业废水处理。
基金financially supported by the National Science Foundation of China (Grant No.21576170)the Opening Project of Material Corrosion and Protection Key Laboratory of Sichuan province (Grant No.2017CL19)~~
文摘以磷铁废渣(Fe1.5P)和温室效应气体CO_2为原料,以磷酸为补充磷源合成磷酸铁锂(LiFePO_4)的前驱体Fe_2P_2O_7,并研究了其合成过程对LiFePO_4正极材料储能性能的影响。采用SEM观察了LiFePO_4的表面形貌,采用XRD分析了LiFePO_4和Fe_2P_2O_7的晶体结构。进一步对该方法进行优化,发现Fe1.5P与磷酸混合物(nFe1.5P∶nH3PO4=1∶1)在800℃热处理6 h合成的Fe_2P_2O_7对应的LiFePO_4/C电化学性能最好,在0.1C,0.2C,0.5C和1C倍率下的容量分别可达130,126,117和108 m Ah·g^(-1)。
文摘利用Fe_2P_2O_7和碳酸锂为原材料,并通过不同的碳包覆合成LiFePO_4/C复合材料.利用XRD、SEM、碳硫分析仪、恒流充放电法和循环伏安对产物的组成、结构、形貌和电化学性能进行测试,确定含碳量为2.45wt%的LiFePO_4/C复合材料具有更好的电化学性能.实验结果表明,在0.1C倍率下,锂离子电池的放电比容量为130.49 m Ah/g,在1C倍率下,锂离子电池的放电比容量为108.58 m Ah/g.
文摘Development of active iron based water oxidation for designing an ideal artificial photosynthesis devices operating under benign neutral pH is highly demanded. We investigated the electrocatalytic activity of Ruddlesden-Pop-per-type strontium ferrite (Sr3Fe2O7) toward the oxygen evolution reaction (OER). Owing to the temperature-dependent efficiency of the charge disproportionation of Fe4+, the OER activity of Sr3Fe2O7 varied with the temperature, and the onset potential for the OER at a neutral pH underwent a negative shift of approximately 200 mV by increasing the temperature for the stabilization of Fe4+. When metal substitution was made to Sr3Fe2O7 for stabilizing Fe4+ at room temperature, the temperature dependence of the OER activity disappeared and the OER was driven at a small overpotential without increasing the temperature, indicating that the stabilization of Fe4+ is substantially important for achieving high OER activity.
基金Project(50604018)supported by the National Natural Science Foundation of China
文摘In order to obtain a new precursor for LiFePO4, Fe2P2O7 with high purity was prepared through solid phase reaction at 650 ℃ using starting materials of FeC2O4 and NH4H2PO4 in an argon atmosphere. Using the as-prepared Fe2P2O7, Li2CO3 and glucose as raw materials, pure LiFePO4 and LiFePO4/C composite materials were respectively synthesized by solid state reaction at 700 ℃ in an argon atmosphere. X-ray diffractometry and scanning electron microscopy（SEM） were employed to characterize the as-prepared Fe2P2O7, LiFePO4 and LiFePO4/C. The as-prepared Fe2P2O7 crystallizes in the Cl space group and belongs to β-Fe2P2O7 for crystal phase. The particle size distribution of Fe2P2O7 observed by SEM is 0.4-3.0 μm. During the Li^＋ ion chemical intercalation, radical P2O7^4- is disrupted into two PO4^3- ions in the presence of O^2-, thus providing a feasible technique to dispose this poor dissolvable pyrophosphate. LiFePO4/C composite exhibits initial charge and discharge capacities of 154 and 132 mA·h/g, respectively.
