Zhang Pengfei, Lu Hanfeng, Zhou Ying, Zhang Li, Wu Zili, Yang Shize, Shi Hongliang, Zhu Qiulian, Chen Yinfei, Dai Sheng
Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Institute of Catalytic Reaction Engineering, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
Nat Commun. 2015 Oct 15;6:8446. doi: 10.1038/ncomms9446.
The development of noble-metal-free heterogeneous catalysts that can realize the aerobic oxidation of C-H bonds at low temperature is a profound challenge in the catalysis community. Here we report the synthesis of a mesoporous Mn0.5Ce0.5Ox solid solution that is highly active for the selective oxidation of hydrocarbons under mild conditions (100-120 °C). Notably, the catalytic performance achieved in the oxidation of cyclohexane to cyclohexanone/cyclohexanol (100 °C, conversion: 17.7%) is superior to those by the state-of-art commercial catalysts (140-160 °C, conversion: 3-5%). The high activity can be attributed to the formation of a Mn0.5Ce0.5Ox solid solution with an ultrahigh manganese doping concentration in the CeO2 cubic fluorite lattice, leading to maximum active surface oxygens for the activation of C-H bonds and highly reducible Mn(4+) ions for the rapid migration of oxygen vacancies from the bulk to the surface.
开发能够在低温下实现C-H键有氧氧化的无贵金属多相催化剂是催化领域面临的一项重大挑战。在此，我们报道了一种介孔Mn0.5Ce0.5Ox固溶体的合成，该固溶体在温和条件（100-120°C）下对烃类的选择性氧化具有高活性。值得注意的是，在将环己烷氧化为环己酮/环己醇的反应中（100°C，转化率：17.7%）所实现的催化性能优于目前最先进的商业催化剂（140-160°C，转化率：3-5%）。这种高活性可归因于在CeO2立方萤石晶格中形成了具有超高锰掺杂浓度的Mn0.5Ce0.5Ox固溶体，从而产生了用于活化C-H键的最大活性表面氧以及用于使氧空位从体相快速迁移到表面的高还原性Mn(4+)离子。
