Tyndall National Institute, University College Cork, Lee Maltings, Dyke Parade, Cork, Ireland.
J Chem Phys. 2013 Nov 14;139(18):184710. doi: 10.1063/1.4829758.
Modification of ceria catalysts is of great interest for oxidation reactions such as oxidative dehydrogenation of alcohols. Improving the reactivity of ceria based catalysts for these reactions means that they can be run at lower temperatures and density functional theory (DFT) simulations of new structures and compositions are proving valuable in the development of these catalysts. In this paper, we have used DFT+U (DFT corrected for on-site Coulomb interactions) to examine the reactivity of a novel modification of ceria, namely, modifying with TiO2, using the example of a Ti2O4 species adsorbed on the ceria (111) surface. The oxygen vacancy formation energy in the Ti2O4-CeO2 system is significantly reduced over the bare ceria surfaces, which together with previous work on ceria-titania indicates that the presence of the interface favours oxygen vacancy formation. The energy gain upon hydrogenation of the catalyst, which is the rate determining step in oxidative dehydrogenation, further points to the improved oxidation power of this catalyst structure.
铈基催化剂的修饰对于氧化反应（如醇的氧化脱氢）具有重要意义。提高基于铈的催化剂在这些反应中的反应性意味着它们可以在更低的温度下运行，并且新结构和组成的密度泛函理论（DFT）模拟在这些催化剂的开发中被证明是有价值的。在本文中，我们使用 DFT+U（用于校正局域库仑相互作用的 DFT）来研究铈的一种新型修饰，即用 TiO2 修饰，以 Ti2O4 物种吸附在 CeO2（111）表面为例。Ti2O4-CeO2 体系中的氧空位形成能明显低于裸铈表面，这与之前关于铈-二氧化钛的研究表明，界面的存在有利于氧空位的形成。催化剂加氢的能量增益，这是氧化脱氢的速率决定步骤，进一步表明了这种催化剂结构的氧化能力得到了提高。
