双碳源在LiFePO4/C微波固相合成中的协同效应

以Li2CO3,FeC2O4·2H2O和NH4 H2 PO4为前驱体,分别以葡萄糖和葡萄糖/乙炔黑为碳源,利用微波加热合成了LiFePO4/C正极材料.用X射线粉末衍射（XRD）和扫描电镜（SEM）对材料进行了表征,用四探针法测定了材料的电导率.研究了碳源与微波温度对材料微结构和电化学性能的影响,发现由于乙炔黑的协同效应,用双碳源在600℃反应即可得到最佳电化学性能的LiFePO4/C,而仅用葡萄糖作碳源反应需要在较高温度（如700℃）下进行.     

Preparation of LiFePO4 for lithium ion battery using Fe2P2O7 as precursor

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 c1 space group and belongs to β-Fe2P2O7 for crystal phase. The particle size distribution of Fe2P2O7 observed by SEM is 0.4-3.0μm. During the Li ion chemical intercalation, radical P2O4-O7 is disrupted into two PO3-4 ions in the presence of O2-, 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.     

磷酸亚铁锂/碳的合成动力学研究

作者以酚醛树脂作为碳源,合成了一系列LiFePO4/C.通过XRD物相分析和晶粒度分析,给出LiFePO4晶粒度与反应温度T、反应时间t之间较完整的函数关系,并求出反应的表观活化能,为优化实验条件提供理论依据.     

Synthesis of Li2Fe0.9Mn0.1SiO4/C composites using glucose as carbon source

Li2Fe0.9Mn0.1SiO4/C composites were synthesized by using glucose as carbon source. The samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and electrochemical measurements. All Li2Fe0.9Mn0.1SiO4/C composites are of the similar crystal structure. With increasing the carbon content in the range of 5%-20% (mass fraction), the diffraction peaks in XRD patterns broaden and the particle sizes and the tap density of samples decrease. The Li2Fe0.9Mn0.1SiO4/C composites with carbon content of 14.12% show excellent the capacity retention remains 92.2% after 30 cycles.     

Microwave Synthesis of Cathode Material LixMn2O4 for Lithium-ion Battery

LixMn2O4 was synthesized rapidly by microwa heaing,the product phases of the microwave synthesis and comventional solid-solid-state synthesis were comparatively inesitigated,The capacity of microwave synthesis product decreases relatively slow,The lithium ion can be inserted into and extracted from the spinel framework structure fluently after cycling .But the capacity of the conventional solid-state synthesis product is more remarkably lowered.The spinel framework structure was destroyed which hindered the lithium ion from inserting and extracting,Tehe influential factors of the process parameters are discussed such as heat preservation time,pre-heating at 400℃ for 24 h and coupled agent.     

Influence of hydrogen concentration on Fe2O3 particle reduction in fluidized beds under constant drag force

The fixed-gas drag force from a model calculation method that stabilizes the agitation capabilities of different gas ratios was used to explore the influence of temperature and hydrogen concentration o...     

草酸铁芬顿、UV/芬顿、暗芬顿降解对硝基酚的效果研究

研究了草酸铁芬顿、ＵＶ／芬顿和暗芬顿工艺中草酸钾,Ｈ２Ｏ２,ＦeSO4浓度,pH值,反应时间和反应温度对降解对硝基酚的影响,得出引入Ｋ２Ｃ２Ｏ４并不能提高对硝基酸酚的降解率,但可以使降解反 在一较宽的pH范围内进行,且缩短了反应时间,ＶＵ／芬顿同暗芬顿对硝基酚具有相同的降解效果,三种工艺降解对硝基酚的最佳条件分别是,草酸铁芬顿：Ｋ２Ｃ２Ｏ４：Ｈ２Ｏ２：ＦeSO4=1:10:1[（化学计量数（旧称摩尔比）],pH=2-6,t=30min,UV/芬顿及暗芬顿,H2O2:FeSO4=10:0.1（化学计量数）,pH=3-4,t=40min,反应温度对降解反应无影响。     

两种芬顿及UV/草酸铁/H2O2法去除间甲酚的研究

研究了UV／草酸铁／H2O2，UV／芬顿和暗芬顿系统中K2C2O4，H2O2，FeSO4浓度，pH值，反应温度，反应时间以及光照条件对间甲酚去除的影响，得出VU／草酸铁／H2O2系统比其他两种系统对间甲酚具有更高的去除率，且使去除反应进行pH范围更宽，并可缩短反应时间。同时证明，自然光照条件下UV／草酸铁／H2O2和UV／芬顿工艺对间甲酚仍有较高的去除率。     

Preparation and electrochemical properties of Co3O4/graphite composites as anodes of lithium ion batteries

Co3O4/graphite composites were synthesized by precipitation of cobalt oxalate on the surface of graphite and pyrolysis of the precipitate, and the effects of graphite content and calcination temperature on the electrochemical properties of the composites were investigated. The samples were characterized by thermogravimetry and differential thermal analysis (TG/DTA), X-ray diffractometry (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and charge/discharge measurements. With increasing the graphite content, the reversible capacity of the Co3O4/graphite composites decreases, while cycling stability improves dramatically, and the addition of graphite obviously decreases the average potential of lithium intercalation/deintercalation. The reversible capacity of the composites with 50% graphite rises from 583 to 725 mAh/g as the calcination temperature increases from 300 to 500 ℃, and the Co3O4/graphite composites synthesized at 400 ℃ show the best cycling stability without capacity loss in the initial 20 cycles. The CV profile of the composite presents two couples of redox peaks, corresponding to the lithium intercalaction/deintercalation for graphite and Co3O4, respectively. EIS studies indicate that the electrochemical impedance decreases with increasing the graphite content.     

UV/Fe(C2O4)33-/H2O2系统羟自由基生成规律

采用分光光度法研究Fenton、UV/Fenton和UV/Fe(C2O4)33-/H2O2系统中羟自由基(.OH)的生成规律.结果表明:3个系统生成的.OH浓度顺序均为UV/Fe(C2O4)33-/H2O2>UV/Fenton>Fenton.对于UV/Fe(C2O4)33-/H2O2系统,最佳K2C2O4浓度为1 mmol/L,最佳初始pH范围和H2O2浓度分别为2-5和20 mmol/L,增加Fe2 浓度和升高反应温度有助于UV/Fe(C2O4)33-/H2O2系统生成.OH.     

超强酸 Fe2O3/SO42- 催化酯化合成乙酸异戊酯

探讨了固体超强酸Ｆｅ２Ｏ３／ＳＯ２－４催化酯化合成乙酸异戊酯的可行性,并讨论了各反应因素对酯化的影响．指出在物料比乙酸∶异戊醇∶甲苯为１∶１．５∶０．５（ｍｏｌ）,催化剂用量为酸醇总量的１０％（ｗ）时,于１３０℃下反应５ｈ,可获得较高酯化产率的乙酸异戊酯．     

Low pressure synthesis of boron nitride with(C2H5)2O·BF3 and Li3N precursor

Cubic boron nitride(c-BN) was synthesized through benzene thermal method at a lower temperature of 300 ℃ by selecting liquid(C2H5)2O·BF3 and Li3N as reactants. Hexagonal boron nitride(h-BN) and orthorhombic boron nitride(o-BN) were also obtained. The samples were characterized by X-ray powder diffractometry and Fourier transformation infrared spectroscopy. The results show that all the BF3, BCl3 and BBr3 in the same family compounds can react with Li3N to synthesize BN since the strongest bond of B-F can be broken. Compared with BBr3, liquid (C2H5)2O·BF3 is cheaper, less toxic and more convenient to operate. Li3N not only provides nitrogen source but also has catalytic effect on accelerating the formation of c-BN at low temperature and pressure.     

Fe_3O_4/SiO_2复合粒子的制备及对Cd~(2+)的吸附性能研究

采用共沉淀法制备出粒径为10nm左右、具有超顺磁性的Fe3O4纳米粒子,在Fe3O4纳米粒子外包覆SiO2合成了磁性Fe3O4/SiO2复合粒子,研究了该复合粒子对水溶液中Cd2+离子的吸附性能.利用透射电子显微镜(TEM)、X射线衍射仪(XRD)、红外光谱(FTIR)、振动样品磁强计(VSM)和原子吸收分光光度计(AAS)对样品进行表征,考察了SiO2不同包覆量对吸附剂吸附性能的影响.结果表明:随着SiO2包覆量的增大,SiO2壳层厚度增大,内核中包埋的Fe3O4粒子数量增多,Fe3O4/SiO2复合粒子尺寸随着增大,由50nm左右增大到300 nm左右;Fe3O4纳米粒子表现出了良好的磁性能,比饱和磁化强度达73.6A·m2·kg-1,Fe3O4/SiO2复合粒子的比饱和磁化强度随SiO2包覆量的增大而逐渐减小;Fe3O4/SiO2复合粒子的吸附率随着SiO2包覆量的增多而逐渐增大,最大吸附率为91.0%.     

Co_(0.5)Zn_(0.5)Fe_2O_4/C复合物的制备及电磁性能研究

采用水热法制备出不同比的Co0.5Zn0.5Fe2O4/C复合物,通过X射线衍射分析仪(XRD)、扫描电镜(SEM)、能谱仪(EDS)、振动样品磁强计(VSM)、网络分析仪对该复合物的形貌、电磁性能进行表征与分析。结果表明:Co0.5Zn0.5Fe2O4被碳包裹程度随碳相对含量的增加而增加;在频率为3~18 GHz范围内,Co0.5Zn0.5Fe2O4/C复合物的介电常数虚部和介电损耗随Co0.5Zn0.5Fe2O4的相对含量增加而增加;与Co0.5Zn0.5Fe2O4相比,Co0.5Zn0.5Fe2O4/C复合物的最大吸收峰有明显提高,且当0.5 g Co0.5Zn0.5Fe2O4与2 g葡萄糖混合时,制备的样品最大吸收峰在频率16 GHz左右可达到7 d B。     

纳米Fe_3O_4/Co_3O_4催化H_2O_2氧化降解亚甲基蓝

纳米四氧化三钴(Co3O4)催化剂对废水中有机物具有良好的催化降解活性,但纳米催化剂难从溶液中分离的缺点限制了其应用.通过将不同量的纳米Co3O4催化剂自组装在纳米四氧化三铁(Fe3O4)上,制备出了一系列不同纳米Co3O4催化剂含量的纳米Fe3O4/Co3O4,并将该系列纳米Fe3O4/Co3O4用于双氧水(H2O2)氧化降解亚甲基蓝的反应来测试其催化性能和回收再利用性能.实验结果表明,尽管纳米Co3O4催化剂的含量对于纳米Fe3O4/Co3O4的催化性能有所影响,但该系列纳米Fe3O4/Co3O4相对纯纳米Co3O4催化剂仍表现出很好的催化活性和回收再利用性.     

Pb(Li_(1/4)Nb_(3/4))O_3-Pb(Mg_(1/3)Nb_(2/3))O_3-Pb(ZrTi)O_3四元系压电变压器陶瓷材料研究

通过Ｐｂ（Ｌｉ１／４Ｎｂ３／４）０．０６（Ｍｇ１／３Ｎｂ２／３）０．０６（Ｚｒ０．８８－ＸＴｉＸ）Ｏ３四元系压电陶瓷材料的改性研究，发现此系列压电材料具有高的Ｋｐ（０．５８）、Ｑｍ（２８００）、ε（１０５０）值，且ｔａｎδＢＮＤ０．００８之内，且具有较好的老化特性，适合作为变压器陶瓷材料使用．用该系统材料制作的压电变压器，具有较高的升压比和机电转换效率．在负载为８８０ＭΩ时，升压比高达１１７０；而当负载为５０ＭΩ时，其机电转换效率最高，为９２％．     

氧化钾对硅酸二钙和无水硫铝酸钙矿物形成的影响

目的 为研究K2O对高硅贝利特硫铝酸盐水泥主要矿物C2S和C4A3S的影响，为含有钾的低品位矿物原料生产高硅贝利特硫铝酸盐水泥奠定了基础．方法 采用f-CaO分析、热分析方法．结果 少量的K2O，降低了f-CaO的质量分数，降低了CaCO3的分解温度及矿物的合成温度．结论 适量的K2O，有利于f-CaO的吸收，降低了C2S和C4A3S矿物及C2S和C4A3S复合矿物合成温度。加速了高硅贝利特硫铝酸盐水泥矿物的形成；除K2O的作用外。复合矿物的相互作用也对这两种矿物的生成尤其是C2S的生成起了一定的促进作用．     

Al2O3对3Ti/Si/2C体系自蔓延高温合成Ti3SiC2的影响

以3Ti/Si/2C粉体为原料,通过自蔓延高温合成技术合成了Ti3SiC2材料。研究了Al2O3助剂对自蔓延高温合成Ti3SiC2的影响。研究结果表明,3Ti/Si/2C粉体会发生自蔓延反应,产物的组成相为TiC、Ti3SiC2和Ti5Si3,产物中Ti3SiC2含量约为23%。添加适量的细粒度Al2O3可显著促进反应合成Ti3SiC2,3Ti/Si/2C/0.1Al2O3原料反应后得到的产物中Ti3SiC2含量达64%。     

Cu-MgO/γ-Al2O3丙酮一步法合成甲基异丁基酮

采用等孔体积浸渍法制备Cu MgO/γ Al2O3丙酮常压气相加氢制MIBK催化剂.通过XRD及BET表面积测定表征催化剂.研究碱性组分及反应条件对转化率和选择性的影响,经筛选得到催化剂体系的最佳组成为:wCu=4%,wMgO=5%,适宜的反应条件为:常压,200℃,H2/丙酮摩尔比为2.5,进料速率为1.5ml·h-1·g-1cat.在该条件下,丙酮转化率达65.26%,MIBK选择性达57.49%.