Department of Materials Science and Engineering, Chungnam National University , 99-Daehakro, Daejeon 34134, Republic of Korea.
Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States.
Nano Lett. 2017 Jan 11;17(1):348-354. doi: 10.1021/acs.nanolett.6b04218. Epub 2016 Dec 8.
The leading edge of catalysis research motivates physical understanding of the growth of nanoscale oxide structures on different supporting oxide materials that are themselves also nanostructured. This research opens up for consideration a diverse range of facets on the support material, versus the single facet typically involved in wide-area growth of thin films. Here, we study the growth of ceria nanoarchitectures on practical anatase titania powders as a showcase inspired by recent experiments. Density functional theory (DFT)-based methods are employed to characterize and rationalize the broad array of low energy nanostructures that emerge. Using a bottom-up approach, we are able to identify and characterize the underlying mechanisms for the facet-dependent growth of various ceria motifs on anatase titania based on formation energy. These motifs include 0D clusters, 1D chains, 2D plates, and 3D nanoparticles. The ceria growth mode and morphology are determined by the interplay of several factors including the role of the common cation valence, the interface template effect for different facets of the anatase support, enhanced ionic binding for more compact ceria motifs, and the local structural flexibility of oxygen ions in bridging the interface between anatase and ceria structures.
催化研究的前沿激励着人们在不同的支撑氧化物材料上对纳米级氧化物结构的生长进行物理理解，而这些支撑氧化物材料本身也是纳米结构的。这项研究为支撑材料的各个方面打开了考虑的空间，而不是通常涉及的在大面积生长薄膜时的单一方面。在这里，我们以最近的实验为灵感，研究了在实用的锐钛矿二氧化钛粉末上氧化铈纳米结构的生长。基于密度泛函理论（DFT）的方法被用来对出现的广泛的低能量纳米结构进行表征和合理化。通过自下而上的方法，我们能够根据形成能来识别和描述基于锐钛矿二氧化钛的各种氧化铈图案在不同晶面上的面依赖性生长的潜在机制。这些图案包括 0D 团簇、1D 链、2D 板和 3D 纳米颗粒。氧化铈的生长模式和形态由多种因素决定，包括常见阳离子价态的作用、锐钛矿支撑体不同晶面的界面模板效应、更紧凑的氧化铈图案的增强离子键合以及在锐钛矿和氧化铈结构之间的界面上的氧离子的局部结构灵活性。
