Seo Jihoon, Lee Jung Woo, Moon Jinok, Sigmund Wolfgang, Paik Ungyu
Department of Energy Engineering, Hanyang University , Seoul 133-791, South Korea.
ACS Appl Mater Interfaces. 2014 May 28;6(10):7388-94. doi: 10.1021/am500816y. Epub 2014 Apr 25.
Ceria nanoparticles (NPs) have been widely explored as a promising material in various fields. As synthesized under various physicochemical conditions, it exhibits the different surface chemistry. Here, the role of hydroxyl and nitrate group on ceria surface, formed under various physicochemical conditions, for the silicate adsorption was experimentally and theoretically investigated based on the adsorption isotherms and theoretical analyses using density functional theory (DFT) calculation. Experimental results acquired from adsorption isotherms with Freundlich model indicated that the nitrate group shows a much higher affinity with silicate than the hydroxyl groups. These phenomena were demonstrated through the theoretical approaches that exhibit the binding energy of the NO3-ceria (-4.383 eV) on the SiO2 surface being much higher than that of the OH-ceria (-3.813 eV). In good agreement with the experimental and the theoretical results based on adsorption properties, the results of chemical mechanical planarization (CMP) also show that the nitrate groups significantly enhance the removal of SiO2 than the hydroxyl groups. The results investigated in this study will provide researchers, studying the ceria NPs, with guidelines on the importance of exploring the surface chemistry of ceria.
二氧化铈纳米颗粒（NPs）作为一种有前景的材料已在各个领域得到广泛研究。在不同的物理化学条件下合成时，它呈现出不同的表面化学性质。在此，基于吸附等温线以及使用密度泛函理论（DFT）计算的理论分析，通过实验和理论研究了在不同物理化学条件下形成的二氧化铈表面的羟基和硝酸根对硅酸盐吸附的作用。从采用弗伦德利希模型的吸附等温线获得的实验结果表明，硝酸根对硅酸盐的亲和力远高于羟基。这些现象通过理论方法得到了证实，该方法表明NO3 - 二氧化铈在SiO2表面的结合能（-4.383 eV）远高于OH - 二氧化铈的结合能（-3.813 eV）。与基于吸附性质的实验和理论结果高度一致，化学机械平面化（CMP）的结果也表明，硝酸根比羟基能显著增强对SiO2的去除。本研究所得结果将为研究二氧化铈纳米颗粒的研究人员提供有关探索二氧化铈表面化学重要性的指导。
