在解剖酶TiO2(101) 表面的小Au和Pt集群:在露台,台阶和表面氧气空缺处的行为
Xue-Qing Gong1, Annabella Selloni, Olga Dulub
1Department of Chemistry, Princeton University, Princeton, New Jersey 08544, and Department of Physics, Tulane University, New Orleans, Louisiana 70118, USA. xgong@ecust.edu.cn
Journal of the American Chemical Society
|December 12, 2007
概括
研究了对二氧化 (TiO2) 表面的金 (Au) 和 (Pt) 纳米集群吸附. Au集群喜欢步骤边缘,而Pt在露台上形成较小的集群,氧气空缺显著影响了Au的生长.
科学领域:
- 材料科学 材料科学 材料科学
- 表面科学是一门学科.
- 计算化学计算化学
背景情况:
- 了解氧化物支上的金属纳米粒子相互作用对于催化和电子学至关重要.
- 二氧化 (TiO2) 解酶 (101) 是一个广泛研究的半导体,在光催化和太阳能电池中具有应用.
- 黄金 (Au) 和 (Pt) 纳米集群在TiO2表面的行为,由于它们的催化性质,具有显著的兴趣.
研究的目的:
- 通过计算来研究Au和Pt纳米集群在TiO2解剖酶上的吸附特性 (101).
- 确定Au和Pt单体,二元和三元体的结构和能量在露台,台阶边缘和氧气空隙上.
- 用扫描道显微镜 (STM) 来实验验证理论预测.
主要方法:
- 密度函数理论 (DFT) 的计算被用来建模吸附结构和能量.
- 系统地确定吸附点,包括干净的露台,台阶边缘 (D-(112) 和氧气空隙.
- 通过蒸汽沉积Au和Pt在TiO2 (101) 上进行实验验证,然后进行STM分析.
主要成果:
- 纳米集群表现出形成大集群的强烈倾向,在干净的TiO2表面上首选在D-(112) 阶段边缘形成核心,这可能是由于动力效应.
- 在露台上观察到包括单体在内的Pt纳米集群,与预测的高结合能为2.2 eV.一致.
- 氧气空缺显著改变了Au集群的增长,而Pt核化行为受到的影响较小.
结论:
- 在TiO2解剖酶 (101) 上,Au和Pt纳米团的吸附行为显著不同,受表面特征和缺陷的影响.
- 阶梯边缘是Au的关键核化地点,而Pt则倾向于露台吸附.
- 氧气空缺在修改TiO2上的Au纳米集群的增长动态方面发挥着至关重要的作用.
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