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在亚纳米-Au集群上对CO氧化产生尺寸依赖的催化活性

Yuqi Wang¹, Haoxiang Xu¹, Jiqin Zhu²

¹State Key Laboratory of Organic-Inorganic Composites, Beijing Key Laboratory of Energy Environmental Catalysis, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China. xuhx@buct.edu.cn.

|September 18, 2024

概括

在CO氧化中黄金 (Au) 亚纳米集群的催化活性取决于大小,0.75nm集群显示峰值质量活性. 特定的位置,如边缘和扭曲,由于最佳吸附能量,比面部更活跃.

科学领域:

* 纳米催化剂的使用
* 表面科学表面科学
* 计算化学计算机化学

背景情况:

*金 (Au) 纳米催化剂表现出高活性,但它们在亚纳米尺寸对催化作用的影响尚不清楚.
*了解这些尺寸效应对于设计高效纳米催化剂至关重要.

研究的目的:

* 系统地研究亚纳米金的尺寸依赖的催化活性.
*阐明几何结构,吸附性质和CO氧化中的催化性能之间的关系.

主要方法:

*采用修订的粒子群优化 (RPSO) 和密度函数理论 (DFT) 来确定Au星团的全球最小结构 (N=2-300,<2.5 nm).
*利用几何结构描述符将集群特征与吸附能量和CO氧化率联系起来.
*在各个集群站点进行了吸附能量和催化活性的高通量评估.

主要成果:

* 在亚纳米 Au 星团的质量活动和星团大小之间观察到火山形的关系,峰值在 0.75 nm 直径.
* 边缘和曲站点与面部站点 (~10^2) 相比,显示出明显更高的周转频率 (~10^6).
* 面部部位上CO和O2的微弱吸附使吸附成为决定速度的步骤,降低了整体活性.

结论:

* 亚纳米金大小极大地影响催化活性,最佳性能在0.75nm.
* 位点特异性活动 (边缘/扭曲与面部) 受到吸附能量的控制,影响速度决定的步骤.
* 这项研究为金子纳米集群的尺寸依赖性催化提供了基本的机械洞察力.

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