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931.
采用基于密度泛函理论的第一性原理赝势平面波方法,研究了Ti掺杂对Li2MgN2H2材料储氢性能的影响及作用机理,计算给出了杂质替换能、生成焓、能带结构、态密度、差分电荷密度及布居等。研究表明,Ti掺杂Li2MgN2H2体系时,其倾向于替换其中的Mg原子,且当替换8c位置的Mg时,杂质替换能最低,晶体结构最为稳定。生成焓计算结果表明,Ti掺杂能够有效降低Li2MgN2H2的结构稳定性,有利于其吸氢反应的进行。进一步结合电子结构分析发现,Ti掺杂使得Li2MgN2H2材料的晶胞体积增大,能隙降低,同时Ti与N原子之间较强的相互作用使得Li—N和N—H键的成键峰峰值降低,键强减弱,这些因素均有利于Li2MgN2H2材料吸氢动力学性能的提高。 相似文献
932.
近年来,二维材料MXene因其优异的电化学性能引起了人们的关注,被广泛应用于电化学储能领域。然而,在组装电极过程中,MXene纳米片往往会产生严重的自堆积效应从而大幅限制了其电化学性能。设计三维结构的气凝胶是解决MXene自堆积问题同时开发高性能MXene基超级电容器电极材料的关键。本文利用氧化石墨烯(GO)改善了Ti3C2Tx气凝胶的力学强度,并通过双向冷铸和冷冻干燥、温和还原的方法制备了具有双向有序结构的Ti3C2Tx/rGO复合气凝胶(A-TGA)。A-TGA具有较好的力学性能和导电性,因此可直接作为超级电容器的电极材料。同时,双向有序的独特结构为电解质离子提供了无阻碍的传输通道,大幅提升了气凝胶的电化学性能。A-TGA在电流密度为1 A·g-1时的比电容为370 F·g-1,在100 mV·s-1扫速下经过5 000次循环后,电容保持率高达94%,表现出优异的循环稳定性。 相似文献
933.
BixOyBrz光催化剂在有机药物废水处理领域有着非常广阔的潜在应用价值,但光生电子-空穴对的快速复合限制了其应用。本文选用具有优良电子传递性能的Ti3C2作为助催化剂,首先利用Ti3C2表面丰富的Ti空位缺陷和高还原能力,制备了Ti3C2-Ru助催化剂,接着利用Ti3C2表面官能团与Bi3+的离子键合力实现了Bi4O5Br2在Ti3C2-Ru表面的原位生长,得到Bi4O5Br2/Ti3C2-Ru复合光催化剂,从而实现了电子由Bi4O5Br2到Ti3C2再到反应活性位点Ru的定向传递,最终使催化剂具有较高的光生载流子分离率和较低的界面电荷转移阻力,有效抑制了光生电子-空穴对的复合。同时以磺胺甲噁唑(SMX)为模拟药物污染物进行了光催化性能测试,结果表明所制备的Bi4O5Br2/Ti3C2-Ru复合光催化剂展示出了优异的光催化降解SMX性能,在可见光下照射75 min,SMX的降解率达到95.1%,相较于纯的Bi4O5Br2和Bi4O5Br2/Ti3C2催化剂,其降解率分别提升了36.9个百分点和25.3个百分点。最后基于自由基捕获实验和催化剂能带结构分析提出了所制催化剂的降解机理。研究结果可为构建具有药物废水净化功能的光催化剂提供设计思路。 相似文献
934.
935.
936.
通过x射线衍射分析和磁性测量对(Nd1-xErx)3Fe273Ti17化合物的结构与磁性进行了研究.单相(Nd1-xErx)3Fe273Ti17化合物的成相范围为x=00—05之间,所有化合物均属于单斜晶系、Nd3(Fe,Ti)29型结构和A2/m空间群.着Er含量的增加,(Nd1-xErx)3Fe273Ti17化合物的晶胞体积、居里温度TC和5K下的饱和磁化强度Ms均单调减小,而5K下的饱和磁化强度Ms和Er含量的关系与稀释模型所描述的结果相一致.(Nd1-xErx)3Fe273Ti1
关键词:
(Nd1-xErx)3Fe273Ti17化合物
磁晶各向异性
自旋重取向
磁相图 相似文献
937.
938.
Effect of Ti substitution on hydrogen storage properties of Zr1−xTixCo (x = 0, 0.1, 0.2, 0.3) alloys
《Journal of Energy Chemistry》2014,23(1):9-14
Zr1−xTixCo (x = 0, 0.1, 0.2, 0.3) alloys were prepared by arc-melting method and the effect of Ti substitution on hydrogen storage properties was studied systematically. Hydrogen desorption pressure-composition-temperature (PCT) measurements were carried out using Sievert's type volumetric apparatus for ZrCo (at 473 K, 573 K and 673 K) and Zr1−xTixCo alloys (at 673 K), respectively. Products after dehydrogenation were characterized by X-ray diffraction (XRD). In addition, the kinetics of Zr1−xTixCo hydride was investigated at 473 K and 673 K, respectively, under hydrogen pressure of 5 MPa. Results showed that Ti substitution for Zr did not change the crystal structure of ZrCo phase. With the increase of temperature from 473 K to 673 K, the extent of disproportionation for ZrCo alloy increased. With Ti content increasing at 673 K, the desorption equilibrium pressure of Zr1−xTixCo-H2 systems elevated and the disproportionation reaction of Zr1−xTixCo alloys was inhibited effectively. Ti substitution decreased the kinetics rate and the effective hydrogen storage capacity of Zr1−xTixCo alloys slightly. Generally speaking, it was found that Zr0.8Ti0.2Co alloy had better anti-disproportionation property with less decrease of effective hydrogen storage capacity which was beneficial to tritium application in the International Thermonuclear Experimental Reactor (ITER). 相似文献
939.
Mikhail F. Butman Nataliya E. Kochkina Nikolay L. Ovchinnikov Karl W. Krmer 《Molecules (Basel, Switzerland)》2021,26(11)
Fibrous Ti/Ce oxide photocatalysts were prepared for the first time by a biomimetic solution process using short flax fibers (flax straw processing waste) as a biotemplate. Titanium polyhydroxy complex solutions with 3% and 5% cerium were used as precursors. Flax fibers were impregnated in an autoclave under hydrothermal conditions. Ti/Ce oxides were obtained from the biotemplate by annealing at 600 °C. The photocatalytic activity of the Ti/Ce oxides was studied by the adsorption and decomposition of the dye rhodamine B under UV irradiation. The photocatalytic decomposition of the dye was 50% and 75% faster for Ti/Ce oxides with 3% and 5% Ce, respectively, than for the analogous undoped fibrous TiO2. The morphologies, textures, and structures of the photocatalysts were studied by scanning electron microscopy, low temperature N2 adsorption/desorption, UV-Vis spectroscopy, and X-ray and XPS analytical methods. It was shown that the introduction of Ce into the precursor solution increased the surface irregularity of the Ti/Ce oxide crystallites compared to pure TiO2. This effect scaled with the Ce concentration. Ce improved the UV light absorption of the material. The Ti/Ce oxides contained Ce4+/Ce3+ pairs that played an important role in redox processes and intensified the photocatalytic activity. 相似文献
940.
Chiara Ferrara Antonio Gentile Stefano Marchionna Riccardo Ruffo 《Current Opinion in Electrochemistry》2021
Since their discovery in 2011, MXene compounds, and in particular the Ti3C2-based phases, have gained increasing interest from researchers leading to over 2000 scientific works in 2020. The peculiar morphological, charge transport, and surface properties make the MXenes ideal materials for energy storage applications such as active material in alkaline ion batteries and supercapacitors, as conductive or buffer agent in composite electrodes for high energy applications, and as electrocatalytic materials for oxygen evolution or redox flow batteries. Among this almost endless literature, this work focuses on 5 recent articles (2019/2020) that summarize the potential of MXenes in different energy storage applications, also resuming the most promising preparatory routes regarding industrial scalability. 相似文献