过渡金属对MXenes的插入:对电子和伪电容性质的影响
Shianlin Wee1, Xiliang Lian2,3, Dario Gomez Vazquez1
1Electrochemical Energy Systems Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland.
将过渡金属插入到Ti3C2Tx MXenes中改变了它们的电子特性,增加了电阻. 选择的特定金属影响氧化还原活性和Ti参与,指导未来的二维材料设计.
科学领域:
- 材料科学
- 电化学
- 表面科学
背景情况:
- 像Ti3C2Tx一样,MXenes是具有可调节电子和电化学特性的二维材料.
- 过渡金属的合提供了一个修改MXene特性的途径.
研究的目的:
- 探究与Ti3C2Tx MXene主体间的氧化还原活性过渡金属 (Ni,Co,Mn,Zn) 的电子相互作用.
- 了解介质如何影响MXenes的电子结构和电阻.
- 与电化学性能相关联的介质性质.
主要方法:
- 用X射线吸收光谱 (XAS) 和巴德电荷分析来确定氧化状态.
- 从初始分子动力学 (AIMD) 和密度功能理论 (DFT) 进行结构和电子分析.
- 伪电容度测量以评估电化学行为.
主要成果:
- 间隔离子氧化状态保持不变,但MXene层中的Ti原子随着间隔剂度的增加而氧化.
- 间隔MXenes的电阻增加.
- DFT和AIMD发现了影响电子属性的不同的阴子安排.
- (Co) 显示显著的氧化还原活性与最小的Ti参与,而 (Ni) 显示微不足道的氧化状态变化与实质性的Ti氧化还原活性.
结论:
- 过渡金属入Ti3C2Tx MXenes导致复杂的电子和氧化还原相互作用.
- 选择的间隔剂显著影响了改造的MXenes的电子结构和电化学反应.
- 通过选择合适的介质物种,这些发现为设计定制的二维材料提供了指导.
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