高度有序的混合价值的半孔性氧化物的形态发生
Jinglu Chen1, Christian Burger, Chirakkal V Krishnan
1Chemistry Department, Stony Brook University, Stony Brook, NY 11794-3400, USA.
Journal of the American Chemical Society
|October 13, 2005
概括
研究人员合成了具有可控制形状和结构的半孔氧化物. 修改聚合物添加剂精确调节粒子形态,用于定制的光电子和光催化应用.
科学领域:
- 材料科学 材料科学 材料科学
- 纳米技术 纳米技术
- 固态化学 固态化学
背景情况:
- 半孔过渡金属氧化物对于光电子和光催化应用至关重要.
- 控制材料的大小,形状和结构是优化其性能的关键.
研究的目的:
- 为了合成具有可控形态的混合价值介质氧化物.
- 研究聚合物添加剂对材料结构和性能的影响.
主要方法:
- 使用超声波照射来减少和分解前体溶液.
- 使用具有不同分子链长度的聚乙烯氧化物作为结构指导剂.
- 以其形态学和晶体结构来表征由此产生的氧化颗粒.
主要成果:
- 成功合成了大规模的,均的氧化颗粒,具有多种类似晶体的形态 (球形,形十二面体,立方体).
- 证明可以通过调整聚乙烯氧化物添加剂的分子链长度来控制粒子形状和结构.
- 在氧化物中证实了具有开放性半孔结构的高度有序立方相的形成 (平均氧化状态为4.8).
结论:
- 这项研究建立了一个简单的方法来控制半孔氧化物的形态.
- 定制粒子形状为调整光电子和光催化性能提供了一条途径.
- 这些发现有助于合理设计先进的功能纳米材料.
相关概念视频
Covalent Bonds
When two atoms share electrons to complete their valence shells they create a covalent bond. An atom’s electronegativity—the force with which shared electrons are pulled towards an atom—determines how the electrons are shared. Molecules formed with covalent bonds can be either polar or nonpolar. Atoms with similar electronegativities form nonpolar covalent bonds; the electrons are shared equally. Atoms with different electronegativities share electrons unequally, creating polar bonds.A Covalent...
Molecular Orbital Theory II
Molecular Orbital Energy Diagrams
Properties of Transition Metals
Transition metals are defined as those elements that have partially filled d orbitals. As shown in Figure 1, the d-block elements in groups 3–12 are transition elements. The f-block elements, also called inner transition metals (the lanthanides and actinides), also meet this criterion because the d orbital is partially occupied before the f orbitals.
Preparation of Diols and Pinacol Rearrangement
Compounds bearing two hydroxyl groups are known as diols. When the hydroxyl groups are located on adjacent carbon atoms, the diols are called vicinal diols or glycols. Under acidic conditions, vicinal diols undergo a specific reaction called pinacol rearrangement.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
Covalent Bonds
Overview
When two atoms share electrons to complete their valence shells, they create a covalent bond. An atom's electronegativity—the force with which shared electrons are pulled towards an atom—determines how the electrons are shared. Molecules formed with covalent bonds can be either polar or nonpolar. Atoms with similar electronegativities form nonpolar covalent bonds; the electrons are shared equally. Atoms with different electronegativities share electrons unequally, creating polar bonds.
When two atoms share electrons to complete their valence shells, they create a covalent bond. An atom's electronegativity—the force with which shared electrons are pulled towards an atom—determines how the electrons are shared. Molecules formed with covalent bonds can be either polar or nonpolar. Atoms with similar electronegativities form nonpolar covalent bonds; the electrons are shared equally. Atoms with different electronegativities share electrons unequally, creating polar bonds.
Heterogeneous Catalysis
Heterogeneous catalysis involves a catalyst in a different phase from the reactants. It is a process where the catalyst and the reactants are in distinct phases, typically solid and gas or liquid.Most heterogeneous catalysts are metals, metal oxides, or acids. The list includes transition metals like iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), manganese (Mn), tungsten (W), silver (Ag), and copper (Cu). These metals possess partially vacant d orbitals that...


