LiNiO_2及掺杂化合物的结构与稳定性的第一性原理研究

应用第一原理局域密度泛函对LiNiO2及其掺杂化合物的晶体结构、能带结构和态密度进行了研究.结果表明:锂镍氧系正极材料是电子的良导体,在充放电过程中具有良好的稳定性,适合做锂离子电池的正极材料;在LiNiO2晶体中主要是O和Ni之间成键,镍离子和氧离子的相互作用比较强,Li在嵌入层状结构材料后部分失去电子,以离子状态存在.

锂离子电池正极材料LiNiO_2及其掺杂化合物

从制备方法、比容量、循环性能，以及安全性能等方面对锂离子电池正极材料ＬｉＮｉＯ２ 及其掺杂化合物有关的研究进展进行讨论，并提出今后研究的方向和途径，

B位双掺杂类钙钛矿化合物La_4BaCu_(5-x-y-)Co_xNi_yO_(13+δ)的制备

运用改进的柠檬酸络合自燃法合成高纯相的B位双掺杂钙钛矿化合物La4BaCu5-x-yCoxNiyO13+δ,采用DTA-TG,XRD,SEM,BET等基础性测试手段对其物相结构、显微形貌等相关物理化学性质进行了基本的表征分析,利用Treor,Retveld等晶胞精修软件对XRD测试结果进行处理,并得到了一些有意义的结果。

掺杂化合物K_3C_(60)晶体的结合能

利用点电荷模型，计算了Ｋ３Ｃ６０晶体的结合能，得出晶格常数为ａ＝１４．３４Ａ，并给出体积弹性模量．

铁掺杂高岭石基纳米TiO_2光催化材料及应用研究

以片状高岭石为基材,采用Fe3+化合和Fe2O3直接热合两种掺杂方法制备铁掺杂高岭石基纳米TiO2光催化材料。应用结果表明,两种掺杂方式均不同程度地提高了材料的光催化活性,且在自然光下的催化效果也有明显提高。该研究对矿物负载型光催化材料在自然光下降解有机物、抗菌、净化空气的工业应用具有重要意义。

铁离子掺杂高岭石基纳米TiO2光催化材料制备及应用研究

选择非金属矿物高岭石作为载体，制备TiO2复合光催化材料，并采用Fe^3＋化合掺杂制备铁掺杂高岭石基纳米TiO2光催化材料。并用其光催化降解含偶氮染料云母珠光颜料工业废水，应用结果表明：Fe^3＋化合掺杂提高了材料的光催化活性且在自然光下的催化效果也有很大的提高．该研究对矿物负载型光催化材料在自然光下降解有机物，抗菌、净化空气的工业应用具有重要意义。

锡掺杂高岭石基纳米TiO_2光催化材料制备及应用研究

以片状高岭石为基材,采用Sn^(4+)化合掺杂方法,制备锡掺杂高岭石基纳米TiO_2光催化材料。应用结果表明:Sn^(4+)化合掺杂提高了材料的光催化活性,且在自然光下的催化效果也有明显提高。该研究对矿物负载型光催化材料在自然光下降解有机物、抗菌、净化空气的工业应用具有重要意义。

Self-assembled S-scheme In_(2.77)S_(4)/K^(+)-doped g-C_(3)N_(4)photocatalyst with selective O_(2) reduction pathway for efficient H_(2)O_(2) production using water and air

The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.

碘离子掺杂的对苯二甲酸铋的可见光催化降解罗丹明B

为研究基于铋的金属有机化合物的可见光活性,利用溶剂热方法,将1.33 mmol硝酸铋和对苯二甲酸首先合成了有机金属化合物对苯二甲酸铋,在此基础上分别掺入相对于硝酸铋物质的量的0.5,0.75,1,2倍的碘化钠后进行溶剂热合成了4种碘离子掺杂的对苯二甲酸铋催化剂,并用红外光谱(IR)、扫描电镜(SEM)、光电子能谱(XPS)、粉末X-射线衍射(XRD)、紫外-可见固体漫反射(UV-Vis DRS)对其进行结构表征.用可见光对20 mg/L的罗丹明B进行降解研究了其光催化性能.结果表明:0.75倍碘化钠掺杂的对苯二甲酸铋显示了很好的可见光降解Rh B催化活性,因为前者表面碘化后对染料的吸附量增大,超氧自由基和光生空穴是可见光降解中的主要活性物种.

Preparation, characterization, and catalytic performance of high efficient CeO_2-MnO_x-Al_2O_3 catalysts for NO elimination

A series of CeO2‐MnOx‐Al2O3 mixed oxide catalysts （Ce：Mn：Al mole ratio=6：4：x, x=0.25, 0.5, 1, 2） were prepared by a simple one‐step inverse co‐precipitation method to investigate the influence of the incorporation of Al3＋ into CeO2‐MnOx mixed oxides. CeO2‐MnOx, CeO2‐Al2O3, and MnOx‐Al2O3 mixed oxides, and CeO2 were prepared by the same method for comparison. The samples were characterized by XRD, Raman, N2 physisorption, H2‐TPR, XPS, and in situ DRIFTS. The catalytic re‐duction of NO by CO was chosen as a model reaction to evaluate the catalytic performance. The incorporation of a small amount of Al3＋into CeO2‐MnOx mixed oxides resulted in a decrease of crys‐tallite size, with the increase of the BET specific surface area and pore volume, as well as the in‐crease of Ce3＋and Mn4＋. The former benefits good contact between catalyst and reactants, and the latter promotes the adsorption of CO and the desorption, conversion and dissociation of adsorbed NO. All these enhanced the catalytic performance for the NO＋CO model reaction. A reaction mecha‐nism was proposed to explain the excellent catalytic performance of CeO2‐MnOx‐Al2O3 catalysts for NO reduction by CO.

A_2BC_(60)和A_3C_(60)晶体中的短程相互作用

研究了Ａ３Ｃ６０和Ａ２ＢＣ６０晶体的结构和稳定性．计算了它们的Ｍａｄｅｌｕｎｇ常数、结合能、晶格常数和体积弹性模量，并讨论了晶体中的短程相互作用．结果显示，短程相互作用对晶体结构和八面体空隙碱金属的稳定性具有极大的影响．ＣｓＫ２Ｃ６０、ＲｂＫ２Ｃ６０和Ｋ３Ｃ６０的晶格常数计算结果与实验测量值非常符合．

基于Fe_3O_4纳米粒子的磁性荧光复合材料研究进展

以磁性Fe3O4纳米粒子为切入点,综述了Fe3O4纳米粒子与发光量子点、镧系稀土离子掺杂化合物以及有机荧光材料复合而得到的纳米复合微粒的制备方法、复合方式、性能特点等;总结了基于Fe3O4纳米粒子的磁光双功能复合材料在材料科学与生物医学等方面的应用,并展望了磁光纳米复合材料的应用前景。

Synthesis of K-doped three-dimensionally ordered macroporous Mn_(0.5)Ce_(0.5)O_δ catalysts and their catalytic performance for soot oxidation

A series of K-doped Mn0.5Ce0.5Oδ （K-MCO） catalysts with three-dimensionally ordered macroporous （3DOM） structure and different K loadings were successfully synthesized using simple methods. These catalysts exhibited well-defined 3DOM nanostructure, which consisted of extensive interconnecting networks of spherical voids. The effects of the calcination temperature and calcination time on the morphological characteristics and crystalline forms of the catalysts were systematically studied. The catalysts showed high catalytic activity for the combustion of soot. 3DOM 20% K-MCO-4h catalyst, in particular, showed the highest catalytic activity of all of the catalysts studied （e.g., Ts0 = 331 ~C and Smco2 = 95.3%）. The occurrence of structural and synergistic effects among the K, Mn, and Ce atoms in the catalysts was favorable for enhancing their catalytic activity towards the combustion of diesel soot. Furthermore, the temperatures required for the complete combustion of the soot （〈400 ℃） were well within the exhaust temperature range （175-400 ℃）, which means that the accumulated soot can be removed under the conditions of the diesel exhaust gas. These catalysts could therefore be used in numerous practical applications because they are easy to synthesize, exhibit high catalytic activity, and can be made from low cost materials.

Preparation, Characterization and Photocatalytic Activity of Fe, La Co-doped Nanometer Titanium Dioxide Photocatalysts

A series of photocatalysts of un-doped, single-doped and co-doped nanometer titanium diox- ide （TiO2） have been successfully prepared by template method using Fe（NO3）3.9H2O, La（NO3）3.6H2O, and tetrabutyl titanate as precursors and glucan as template. Scanning electron microscopy, X-ray diffraction, and N2 adsorption-desorption measurement were employed to characterize the morphology, crystal structure and surface structure of the samples. The photo-absorbance of the obtained catalysts was measured by UV-Vis absorption spectroscopy, and the photocatalytic activities of the prepared samples under UV and visible light were estimated by measuring the degradation rate of methyl orange in an aqueous solution. The characterizations indicated that the prepared photocatalysts consisted of anatase phase and possessed high surface area of ca. 163-176 m2/g. It was shown that the Fe and La co-doped nano-TiO2 could be activated by visible light and could thus be used as an effective catalyst in photo-oxidation reactions. The synergistic effect of Fe and La co-doping played an important role in improving the photocatalytic activity. In addition, the possibility of cyclic usage of co-doped nano-TiO2 was also confirmed, the photocatalytic activity of codoped nano-TiO2 remained above 89.6% of the fresh sample after being used four times.

Effect of carbon on microstructures of Ti-45Al-3Fe-2Mo-xC alloy

The effect of carbon addition on the microstructures of TiAl-based alloy（Ti-45Al-3Fe-2Mo） was studied.The proportion of β/B2 phase reduces with the content of carbon increasing,while the colony size increases.With increasing the carbon content,the lamellar spacing first decreases from 267 nm（Ti-45Al-3Fe-2Mo） to 237 nm（Ti-45Al-3Fe-2Mo-0.3C） and 155 nm（Ti-45Al-3Fe-2Mo-0.5C）,but then increases to 230 nm（Ti-45Al-3Fe-2Mo-1.0C） with further increase in C level,which is affected by the inhibition of carbon atom and precipitation of carbides at the lamellar interface.Precipitation of carbides shows a response to aging time at 800 ℃.P-type carbides grow up at the boundaries and near the dislocation areas with the prolonging of aging time.And these carbides are projected different morphology in different beam directions（BD）.The effects of these microstructural modifications were examined and the observations were discussed.

(TiO_2)_(12)量子环及过渡金属化合物掺杂对其电子性质影响的密度泛函理论研究

本文采用第一性原理中基于密度泛函理论(DFT)的广义梯度近似(GGA)方法,设计了一种新的(TiO2)12量子环结构,研究了它的几何结构、平均结合能及电子云分布等属性.在此新型结构的基础上,分别采用过渡金属化合物MoS2,Mo Se2,Mo Te2,WS2,WSe2和WTe2进行掺杂,并分析了掺杂后体系的几何结构及电子属性(如平均结合能、能级结构、HOMO-LUMO轨道电子云密度分布和电子态密度等).计算结果表明:(TiO2)12量子环直径为1.059 nm,呈中心对称分布,且所有原子组成一个二维平面结构,使其几何结构比较稳定,另外该量子环HOMO-LUMO轨道电子云分布均匀,且能隙为3.17eV,与半导体材料TiO2晶体的能隙的实验值(3.2 eV)非常接近.掺杂后量子环的能隙均大幅减小,其中WTe2的掺杂结果能隙最小,仅为0.61eV,Mo Te2的掺杂结果能隙最大,为1.16 eV,也比掺杂前减小约2.0 eV.其他掺杂结果的能隙都在1eV左右,变化不大.这个能隙的TiO2可以利用大部分的太阳光能,使TiO2具有更为广泛的应用.

Hydrogen storage behaviors and microstructure of MF_3(M=Ti,Fe)-doped magnesium hydride

MgH2+10%MF3(M=Ti,Fe)(mass fraction) composites were prepared by ball-milling in hydrogen atmosphere,and their hydrogen storage behaviors and microstructure were investigated systematically.The results show that the hydriding and dehydriding kinetics of MgH2 are markedly improved by doping TiF3 and FeF3 fluorides.At 573 K,the two composites can absorb 5.67%-6.07%(mass fraction) hydrogen within 5 min under an initial hydrogen pressure of 3.5 MPa,and desorb 5.34%-6.02% hydrogen within 6 min.Furthermore,the composites can absorb hydrogen rapidly in moderate temperature range of 313-473 K.In comparison,TiF3-doped sample has a better hydriding-dehydriding kinetics than FeF3-doped sample.The microstructure analysis shows that some active particles including MgF2,TiH2 and Fe could be formed in the hydriding-dehydriding processes of the MF3-doped composites.From the Kissinger's plot,the apparent activation energies for the hydrogen desorption of the composites are estimated to be 74.1 kJ/mol for TiF3-doped composite and 77.6 kJ/mol for FeF3-doped composite,indicating MgH2 is significantly activated due to the catalytic effect of the doping of MF3.

The photocatalytic performance and active sites of g-C3N4 effected by the coordination doping of Fe(Ⅲ)

Element doping is a simple and effective method to improve photocatalytic activity of g-C3N4. However, the doping model and mechanism of metal elements are still uncharacterized. In this study, we found that Fe(Ⅲ) can be doped into g-C3N4 through the coordination between amidogen and Fe(Ⅲ). After activity tests, it was found that this coordination doping of Fe(Ⅲ) could enhance the Rh B oxidation and Cr(Ⅵ) reduction activities of g-C3N4 in interesting ways, but it is not helpful for the NO-removal performance of g-C3N4. Characterization and calculation results show that the coordination of Fe(Ⅲ) can not only improve the transfer of photogenerated electrons, but it also can passivate the carbon site of triazine rings, which is the active site of NO-removal. This study revealed some doping mechanisms and effect mechanisms of elemental metal in photocatalysis.

Using HF rather than NH_4F as doping source for spray-deposited SnO_2:F thin films

Fluorine doped tin oxide SnO2：F thin films were prepared by the spray pyrolysis （SP） technique on glass substrates by using SnC12.2H2O as a precursor and NH4F and HF as doping compounds. A comparison between the properties of the films obtained by using the two doping compounds was performed by using I-V characteristics in the dark at room temperature, AC measurements, and transmittance. It is found that the films prepared by using HF have smaller resistivity, lower impedance and they are less capacitive than films prepared by using NH4F. In addition, these films have higher transmittance, higher optical bandgap energy and narrower Urbach tail width. These results are interesting for the use of SnO2：F as forecontact in CdS/CdTe solar cells.

A Novel Mo-Doped Compound with Graphite-Like Structure: [H_3O]_2V_3O_8

The hydrothermal reaction of Na2MoO4 . 2H(2)O, V2O5 and en in water gave rise to a graphite-shaped vanadate [H3O](2)V3O8 1, which is doped with molybdenum. Compound 1 crystallizes in tetragonal system, space group P4bm, H6O10V2.9Mo0.1, M-r = 323.37, a = 8.904(1), c = 5.573(1)Angstrom, V = 441.8(1)Angstrom (3), Z = 2, D-c = 2.431 g.cm(-3), mu = 3.137 mm(-1), F(000) = 314, the final R = 0.0477, wR = 0.0993 for 260 observed reflections. Its two-dimensional framework is built up by corner-shared ((VO4)-O-V) tetrahedra and ((VO5)-O-IV) square pyramids with all of the terminal oxygen atoms toward the same orientation and further connected inta three-dimensional framework through hydrogen bonding between the protoned water molecules.