近年来,自旋电子学的发展与应用已经使科研工作者在计算机存储等领域的研究取得极大进展。采用基于密度泛函理论的第一性原理方法,运用美国Materials Studio 6.0 CASTEP软件计算金属化合物Mn4N的性质。首先,从量子力学的角度考虑电子的...近年来,自旋电子学的发展与应用已经使科研工作者在计算机存储等领域的研究取得极大进展。采用基于密度泛函理论的第一性原理方法,运用美国Materials Studio 6.0 CASTEP软件计算金属化合物Mn4N的性质。首先,从量子力学的角度考虑电子的电荷特性和自旋特性,建立Mn4N的结构模型,计算最优化晶格常数、能带结构和态密度,确定其体模量、剪切模量、杨氏模量和泊松比,计算得到最优化晶格常数为3.838。其次,在几何优化的基础上,计算Mn4N的磁性性质,总磁矩为-0.82μB,说明其为良好的亚铁磁性金属材料,磁性主要来源于Mn1原子和Mn2原子d电子的自旋及其在费米能级附近劈裂和相互杂化。展开更多
为抑制高能锂离子电池负极材料Bi2Mn4O10容量的快速衰减,通过简单球磨法制备新型高纯Bi2Mn4O10/ECP-N(ECP-N为氮掺杂科琴黑)负极复合材料。所合成的Bi2Mn4O10/ECP-N复合材料在0.2C倍率下循环100次后可保持576.2m A·h/g的比容量,容...为抑制高能锂离子电池负极材料Bi2Mn4O10容量的快速衰减,通过简单球磨法制备新型高纯Bi2Mn4O10/ECP-N(ECP-N为氮掺杂科琴黑)负极复合材料。所合成的Bi2Mn4O10/ECP-N复合材料在0.2C倍率下循环100次后可保持576.2m A·h/g的比容量,容量保持率为75%,而纯Bi2Mn4O10的容量保持率仅为27%。3C倍率下Bi2Mn4O10/ECP-N复合材料的放电容量仍保持在236.1 m A·h/g。引入氮掺杂的科琴黑ECP-N不仅可以有效地提高比表面积以缓冲体积膨胀,增强材料的电导率和可湿性,而且还可以促进离子传输和可逆转化反应。展开更多
采用基于密度泛函理论(DFT)的第一性原理计算方法,计算了Mn4Si7及Mo掺杂Mn4Si7的电子结构和光学性质。计算结果表明Mn4Si7的禁带宽度Eg=0.804 e V,Mo掺杂Mn4Si7的禁带宽度Eg=0.636 e V。掺杂使得Mn4Si7费米面附近的电子结构发生改变,导...采用基于密度泛函理论(DFT)的第一性原理计算方法,计算了Mn4Si7及Mo掺杂Mn4Si7的电子结构和光学性质。计算结果表明Mn4Si7的禁带宽度Eg=0.804 e V,Mo掺杂Mn4Si7的禁带宽度Eg=0.636 e V。掺杂使得Mn4Si7费米面附近的电子结构发生改变,导带底由Γ点转移为Y点向低能方向下偏移,价带顶向高能方向上偏移,带隙变窄。计算还表明Mo掺杂Mn4Si7使介电函数、折射率、吸收系数及光电导率等光学性质增加。展开更多
The understanding of the structure-function relationship of the oxygen-evolving center(OEC), a Mn_4 Cacluster, in photosystem II is impeded mainly due to the complexity of the protein environment and lack of rational ...The understanding of the structure-function relationship of the oxygen-evolving center(OEC), a Mn_4 Cacluster, in photosystem II is impeded mainly due to the complexity of the protein environment and lack of rational chemical models as a reference. In this study, two novel Mn_4-oxido complexes have been synthesized and characterized, in which the peripheral ligands of the [Mn_4~Ⅲ] core are provided by eight μ_2-carboxylate groups and two neutral terminal ligands(pyridine or isoquinoline). This type of peripheral ligation is very similar to the Mn_4Ca-oxide model complexes recently reported to mimic the OEC. The new Mn_4-oxide complex can catalyze the oxygen-evolving reaction in the presence of Bu^tOOH as an oxidant. The structure and redox properties comparison of the Mn_4-oxido and Mn_4Ca-oxido complexes provide important clues to understanding the functional role of Ca in the OEC in natural photosynthesis, and develop more efficient artificial catalysts for the water-splitting reaction in the future.展开更多
文摘近年来,自旋电子学的发展与应用已经使科研工作者在计算机存储等领域的研究取得极大进展。采用基于密度泛函理论的第一性原理方法,运用美国Materials Studio 6.0 CASTEP软件计算金属化合物Mn4N的性质。首先,从量子力学的角度考虑电子的电荷特性和自旋特性,建立Mn4N的结构模型,计算最优化晶格常数、能带结构和态密度,确定其体模量、剪切模量、杨氏模量和泊松比,计算得到最优化晶格常数为3.838。其次,在几何优化的基础上,计算Mn4N的磁性性质,总磁矩为-0.82μB,说明其为良好的亚铁磁性金属材料,磁性主要来源于Mn1原子和Mn2原子d电子的自旋及其在费米能级附近劈裂和相互杂化。
基金Project(2019zzts502)supported by the Fundamental Research Funds for the Central Universities of Central South University,ChinaProject(2018GK4001)supported by the Scientific and Technological Breakthrough and Major Achievements Transformation of Strategic Emerging Industries of Hunan Province,China。
文摘为抑制高能锂离子电池负极材料Bi2Mn4O10容量的快速衰减,通过简单球磨法制备新型高纯Bi2Mn4O10/ECP-N(ECP-N为氮掺杂科琴黑)负极复合材料。所合成的Bi2Mn4O10/ECP-N复合材料在0.2C倍率下循环100次后可保持576.2m A·h/g的比容量,容量保持率为75%,而纯Bi2Mn4O10的容量保持率仅为27%。3C倍率下Bi2Mn4O10/ECP-N复合材料的放电容量仍保持在236.1 m A·h/g。引入氮掺杂的科琴黑ECP-N不仅可以有效地提高比表面积以缓冲体积膨胀,增强材料的电导率和可湿性,而且还可以促进离子传输和可逆转化反应。
文摘采用基于密度泛函理论(DFT)的第一性原理计算方法,计算了Mn4Si7及Mo掺杂Mn4Si7的电子结构和光学性质。计算结果表明Mn4Si7的禁带宽度Eg=0.804 e V,Mo掺杂Mn4Si7的禁带宽度Eg=0.636 e V。掺杂使得Mn4Si7费米面附近的电子结构发生改变,导带底由Γ点转移为Y点向低能方向下偏移,价带顶向高能方向上偏移,带隙变窄。计算还表明Mo掺杂Mn4Si7使介电函数、折射率、吸收系数及光电导率等光学性质增加。
基金supported by the National Natural Science Foundation of China (20973186,31070216,21076049,and 91427303)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB17030600)
文摘The understanding of the structure-function relationship of the oxygen-evolving center(OEC), a Mn_4 Cacluster, in photosystem II is impeded mainly due to the complexity of the protein environment and lack of rational chemical models as a reference. In this study, two novel Mn_4-oxido complexes have been synthesized and characterized, in which the peripheral ligands of the [Mn_4~Ⅲ] core are provided by eight μ_2-carboxylate groups and two neutral terminal ligands(pyridine or isoquinoline). This type of peripheral ligation is very similar to the Mn_4Ca-oxide model complexes recently reported to mimic the OEC. The new Mn_4-oxide complex can catalyze the oxygen-evolving reaction in the presence of Bu^tOOH as an oxidant. The structure and redox properties comparison of the Mn_4-oxido and Mn_4Ca-oxido complexes provide important clues to understanding the functional role of Ca in the OEC in natural photosynthesis, and develop more efficient artificial catalysts for the water-splitting reaction in the future.
