以石墨烯为基底,用水热法制备蜂窝状钴酸锌（ZnCo2O4）/还原氧化石墨烯（rGO）微球复合材料。用XRD、SEM分析复合材料的结构和形貌,用恒流充放电及循环伏安法测试复合材料的电化学性能。石墨烯的加入,可改变ZnCo2O4颗粒的形貌,并改善复...以石墨烯为基底,用水热法制备蜂窝状钴酸锌（ZnCo2O4）/还原氧化石墨烯（rGO）微球复合材料。用XRD、SEM分析复合材料的结构和形貌,用恒流充放电及循环伏安法测试复合材料的电化学性能。石墨烯的加入,可改变ZnCo2O4颗粒的形貌,并改善复合材料作为锂离子电池负极活性物质的电化学性能。以500 m A/g的电流在0.013.00 V循环,复合材料的首次放电比容量为1 326.7 m Ah/g,第70次循环的放电比容量为1 212.4 m Ah/g。展开更多
通过液相共沉淀法获得Zn和Co的前驱,经过600℃煅烧处理获得ZnCo_2O_4纳米颗粒组装的毛线团状的微球。电化学测试表明,在0.5 A·g^(-1)的电流密度下循环200次可逆比容量保持为965 m Ah·g^(-1);在0.8 A·g^(-1)的电流密度下...通过液相共沉淀法获得Zn和Co的前驱,经过600℃煅烧处理获得ZnCo_2O_4纳米颗粒组装的毛线团状的微球。电化学测试表明,在0.5 A·g^(-1)的电流密度下循环200次可逆比容量保持为965 m Ah·g^(-1);在0.8 A·g^(-1)的电流密度下循环350次可逆比容量保持为882 m Ah·g^(-1)。倍率性能测试表明在2 A·g^(-1)的电流密度时可逆比容量为736 m Ah·g^(-1)。展开更多
The leaching kinetics of low grade zinc oxide ore in NH3-NH4Cl-H2O system was studied. The effects of ore particle size, reaction temperature and the sum concentration of ammonium ion and ammonia on the leaching effic...The leaching kinetics of low grade zinc oxide ore in NH3-NH4Cl-H2O system was studied. The effects of ore particle size, reaction temperature and the sum concentration of ammonium ion and ammonia on the leaching efficiency of zinc were examined. The leaching kinetics of low-grade zinc oxide ore in NH3-NH4Cl-H2O system follows the kinetic law of shrinking-core model. The results show that diffusion through the inert particle pores is the leaching kinetics rate controlling step. The calculated apparent activation energy of the process is about 7.057 kJ/mol. The leaching efficiency of zinc is 92.1% under the conditions of ore particle size of 69 μm, holding at 80 ℃ for 60 min, sum ammonia concentration of 7.5 mol/L, the molar ratio of ammonium to ammonia being 2-1, and the ratio (g/mL) of solid to liquid being 1-10.展开更多
The cobalt ferrite nanoparticles were prepared by coprecipitation in the presence of poly (N-vinylpyrrolidone) (PVP) and characterized by XRD, TEM, EDX and magnetometry. XRD results suggest the formation of pure cobal...The cobalt ferrite nanoparticles were prepared by coprecipitation in the presence of poly (N-vinylpyrrolidone) (PVP) and characterized by XRD, TEM, EDX and magnetometry. XRD results suggest the formation of pure cobalt ferrite. The mean particle sizes of CoFe2O4 samples annealed at 400 ℃ and 600 ℃ were ca. 6 and 25 nm, respectively as obtained by transmission electron microscopy (TEM). The magnetic measurements indicated that nano-particles obtained at 400 ℃ were superparamagnetic while that prepared at 600 ℃ were ferrimagnetic.展开更多
A new method has been developed for separation and determination of zinc,copper,cobalt and nickel based on their colour chelates with 6,6″-dimethyl-4′-phenyl-2,2′:6′,2″-terpyridine（TPY） by ion pair high perform...A new method has been developed for separation and determination of zinc,copper,cobalt and nickel based on their colour chelates with 6,6″-dimethyl-4′-phenyl-2,2′:6′,2″-terpyridine（TPY） by ion pair high performance liquid chromatography in a reversed phase mode.The suitable conditions are the methanol-water（80:20,V/V） containing 10mmol/L NaH2PO4-H3PO4 buffer solution（pH=5.0） and 3.0mmol/L sodium dodecyl sulfonate as mobile phase,on a Symmetry C18 column（3.9mmID×150mm）,the flow rate of the mobile phase is 1.0mL/min.Spectrophotometric detection was made at 340nm.The detective limits are 0.05,0.10,2.00 and 0.50ng/mL respectively.The method has good selectivity and sensitivity.It has been applied to the separation and determination of zinc,copper,cobalt and nickel in human hair and tobacco and the result is satisfied.展开更多
采用微波液相辅助法及退火处理制备了纳米花结构的钴酸锌(ZnCo_2O_4),并考察了不同退火温度对材料性能的影响。利用X射线衍射(XRD)仪、扫描电镜(SEM)、循环伏安(CV)法、电化学阻抗谱(EIS)和恒流充放电测试,对所制备材料的晶体结构、形...采用微波液相辅助法及退火处理制备了纳米花结构的钴酸锌(ZnCo_2O_4),并考察了不同退火温度对材料性能的影响。利用X射线衍射(XRD)仪、扫描电镜(SEM)、循环伏安(CV)法、电化学阻抗谱(EIS)和恒流充放电测试,对所制备材料的晶体结构、形貌以及电化学性能进行了分析。分析结果表明:不同退火温度均能制备出尖晶石结构的ZnCo_2O_4。随着退火温度的升高,ZnCo_2O_4纳米花趋于团聚。400℃退火制备的ZnCo_2O_4纳米花具有较好的电化学性能。在200 m A·g^(-1)的电流密度,经过50圈循环后,比容量仍高达673. 5 m A·h·g^(-1),对应的库伦效率为97. 5%,表现出了良好的循环性能和高充放电比容量。展开更多
基金Research Project from Department of Science and Technology of Shandong Province(2012GGA01012)Scientific ResearchFoundation for the Returned Overseas Chinese Scholars of State Education Ministry(2004-527)
文摘以石墨烯为基底,用水热法制备蜂窝状钴酸锌（ZnCo2O4）/还原氧化石墨烯（rGO）微球复合材料。用XRD、SEM分析复合材料的结构和形貌,用恒流充放电及循环伏安法测试复合材料的电化学性能。石墨烯的加入,可改变ZnCo2O4颗粒的形貌,并改善复合材料作为锂离子电池负极活性物质的电化学性能。以500 m A/g的电流在0.013.00 V循环,复合材料的首次放电比容量为1 326.7 m Ah/g,第70次循环的放电比容量为1 212.4 m Ah/g。
文摘通过液相共沉淀法获得Zn和Co的前驱,经过600℃煅烧处理获得ZnCo_2O_4纳米颗粒组装的毛线团状的微球。电化学测试表明,在0.5 A·g^(-1)的电流密度下循环200次可逆比容量保持为965 m Ah·g^(-1);在0.8 A·g^(-1)的电流密度下循环350次可逆比容量保持为882 m Ah·g^(-1)。倍率性能测试表明在2 A·g^(-1)的电流密度时可逆比容量为736 m Ah·g^(-1)。
基金Project(2007CB613604) supported by the Major State Basic Research Development Program of ChinaProject(50674104) supported by the National Natural Science Foundation of ChinaProject(GJJ08279) supported by the Department of Education of Jiangxi Province
文摘The leaching kinetics of low grade zinc oxide ore in NH3-NH4Cl-H2O system was studied. The effects of ore particle size, reaction temperature and the sum concentration of ammonium ion and ammonia on the leaching efficiency of zinc were examined. The leaching kinetics of low-grade zinc oxide ore in NH3-NH4Cl-H2O system follows the kinetic law of shrinking-core model. The results show that diffusion through the inert particle pores is the leaching kinetics rate controlling step. The calculated apparent activation energy of the process is about 7.057 kJ/mol. The leaching efficiency of zinc is 92.1% under the conditions of ore particle size of 69 μm, holding at 80 ℃ for 60 min, sum ammonia concentration of 7.5 mol/L, the molar ratio of ammonium to ammonia being 2-1, and the ratio (g/mL) of solid to liquid being 1-10.
文摘The cobalt ferrite nanoparticles were prepared by coprecipitation in the presence of poly (N-vinylpyrrolidone) (PVP) and characterized by XRD, TEM, EDX and magnetometry. XRD results suggest the formation of pure cobalt ferrite. The mean particle sizes of CoFe2O4 samples annealed at 400 ℃ and 600 ℃ were ca. 6 and 25 nm, respectively as obtained by transmission electron microscopy (TEM). The magnetic measurements indicated that nano-particles obtained at 400 ℃ were superparamagnetic while that prepared at 600 ℃ were ferrimagnetic.
文摘A new method has been developed for separation and determination of zinc,copper,cobalt and nickel based on their colour chelates with 6,6″-dimethyl-4′-phenyl-2,2′:6′,2″-terpyridine（TPY） by ion pair high performance liquid chromatography in a reversed phase mode.The suitable conditions are the methanol-water（80:20,V/V） containing 10mmol/L NaH2PO4-H3PO4 buffer solution（pH=5.0） and 3.0mmol/L sodium dodecyl sulfonate as mobile phase,on a Symmetry C18 column（3.9mmID×150mm）,the flow rate of the mobile phase is 1.0mL/min.Spectrophotometric detection was made at 340nm.The detective limits are 0.05,0.10,2.00 and 0.50ng/mL respectively.The method has good selectivity and sensitivity.It has been applied to the separation and determination of zinc,copper,cobalt and nickel in human hair and tobacco and the result is satisfied.
文摘采用微波液相辅助法及退火处理制备了纳米花结构的钴酸锌(ZnCo_2O_4),并考察了不同退火温度对材料性能的影响。利用X射线衍射(XRD)仪、扫描电镜(SEM)、循环伏安(CV)法、电化学阻抗谱(EIS)和恒流充放电测试,对所制备材料的晶体结构、形貌以及电化学性能进行了分析。分析结果表明:不同退火温度均能制备出尖晶石结构的ZnCo_2O_4。随着退火温度的升高,ZnCo_2O_4纳米花趋于团聚。400℃退火制备的ZnCo_2O_4纳米花具有较好的电化学性能。在200 m A·g^(-1)的电流密度,经过50圈循环后,比容量仍高达673. 5 m A·h·g^(-1),对应的库伦效率为97. 5%,表现出了良好的循环性能和高充放电比容量。
