DFT研究通过溢出在有氧表面群的石墨上储存的研究
George M Psofogiannakis1, George E Froudakis
1Department of Chemistry, University of Crete, P.O. Box 2208, Voutes, Heraklion Crete, 710 03, Greece.
Journal of the American Chemical Society
|November 19, 2009
概括
密度功能理论 (DFT) 建模揭示了氧功能组增强了储存在碳的溢出. 然而,由基组形成的水可能会对储存能力产生负面影响.
科学领域:
- 材料科学 材料科学 材料科学
- 物理化学 物理化学
- 计算化学计算化学
背景情况:
- 在碳中储存气对于清洁能源至关重要.
- 碳材料上的氧功能组可以影响吸附和储存机制.
- 了解溢出机制是优化储能容量的关键.
研究的目的:
- 用DFT阐明环氧和基函数组在石墨氧化物和氧化碳的溢出机制中的作用.
- 为了研究这些功能化碳表面上气溢出所涉及的基本步骤和能源障碍.
主要方法:
- 使用密度函数理论 (DFT) 建模.
- 构建了一个主要溢出模型,包括一个Pt(4) 集群,一个石墨基板模型,以及被吸附的O和OH函数组.
- 计算的重点是原子迁移路径和能量障碍.
主要成果:
- 溢出通过从Pt集群迁移到环氧群,形成基群.
- 随后的气迁移发生在吸附的氧原子上跳跃.
- 这些步骤的低能耗障碍表明容易溢出氧功能化碳,增强的吸收和动力学.
- 确定了一个竞争的反应路径,从表面基组形成水,可能会阻碍储存.
结论:
- 氧的功能性,特别是环氧和基,大大促进了在碳材料上的溢出.
- 已确定的溢出途径表明增强了储存和充/放电率.
- 对于使用这种方法的长期储应用来说,水形成的潜力是一个挑战.
相关概念视频
00:26Hydrogen Bonds
Hydrogen BondsHydrogen bonds are weak attractions between atoms that have formed other chemical bonds. One of these atoms is electronegative, like oxygen, and has a partial negative charge. The other is a hydrogen atom that has bonded with another electronegative atom and has a partial positive charge.Hydrogen Bonds Control the World!Because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom, such as oxygen or nitrogen, electrons in the bond are...
01:04Hydrogen Bonds
A hydrogen bond is formed when a weakly positive hydrogen atom already bonded to one electronegative atom (for example, the oxygen in the water molecule) is attracted to another electronegative atom from another polar molecule, such as water (H2O), hydrogen fluoride (HF), or ammonia (NH3). The huge electronegativity difference between the H atom (2.1) and the atom to which it is bonded (4.0 for an F atom, 3.5 for an O atom, or 3.0 for an N atom), combined with the very small size of an H atom...
03:35Hybridization of Atomic Orbitals II
sp3d and sp3d 2 Hybridization
03:24Hybridization of Atomic Orbitals I
The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals. The new orbitals that...
01:28Adsorption of Gases on Solids
Adsorption is a process where molecules, known as the adsorbates, accumulate on a surface, which is referred to as the adsorbent or substrate. Occurring at the solid-gas interface, this phenomenon is crucial in various scientific and industrial contexts. The reverse of adsorption is desorption.Two types of adsorptions exist: physical (physisorption) and chemical (chemisorption). Physisorption involves gas molecules held to the solid's surface by relatively weak intermolecular van der Waals...