Kim Byung-Hyun, Kullgren Jolla, Wolf Matthew J, Hermansson Kersti, Broqvist Peter
Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden.
Platform Technology Laboratory, Korea Institute of Energy Research, Daejeon, South Korea.
Front Chem. 2019 May 22;7:203. doi: 10.3389/fchem.2019.00203. eCollection 2019.
The interface formation and its effect on redox processes in agglomerated ceria nanoparticles (NPs) have been investigated using a multiscale simulation approach with standard density functional theory (DFT), the self-consistent-charge density functional tight binding (SCC-DFTB) method, and a DFT-parameterized reactive force-field (ReaxFF). In particular, we have modeled CeO NP pairs, using SCC-DFTB and DFT, and longer chains and networks formed by CeO or CeO NPs, using ReaxFF molecular dynamics simulations. We find that the most stable {111}/{111} interface structure is coherent whereas the stable {100}/{100} structures can be either coherent or incoherent. The formation of {111}/{111} interfaces is found to have only a very small effect on the oxygen vacancy formation energy, . The opposite holds true for {100}/{100} interfaces, which exhibit significantly lower values than the bare surfaces, despite the fact that the interface formation eliminates reactive {100} facets. Our results pave the way for an increased understanding of ceria NP agglomeration.
采用标准密度泛函理论（DFT）、自洽电荷密度泛函紧束缚（SCC-DFTB）方法和DFT参数化反应力场（ReaxFF）的多尺度模拟方法，研究了团聚氧化铈纳米颗粒（NPs）中的界面形成及其对氧化还原过程的影响。特别是，我们使用SCC-DFTB和DFT对CeO NP对进行了建模，并使用ReaxFF分子动力学模拟对由CeO或CeO NPs形成的更长链和网络进行了建模。我们发现，最稳定的{111}/{111}界面结构是相干的，而稳定的{100}/{100}结构可以是相干的或不相干的。发现{111}/{111}界面的形成对氧空位形成能仅有非常小的影响。{100}/{100}界面则相反，尽管界面形成消除了活性{100}面，但它们的 值明显低于裸露表面。我们的结果为深入理解氧化铈NP团聚铺平了道路。
