State Key Laboratory of Heavy Oil Processing, College of Science , China University of Petroleum , Beijing 102249 , People's Republic of China.
Environ Sci Technol. 2020 Feb 4;54(3):2002-2011. doi: 10.1021/acs.est.9b07013. Epub 2020 Jan 10.
Optimized surface facet of the catalysts is an efficient strategy to boost catalytic purification of diesel soot as important components of atmospheric fine particles. Herein, we have elaborately constructed the nanocatalysts of Au nanoparticles supported on the well-defined CeO (rod, cube, and polyhedron) with predominantly exposed facets of {110}, {100}, and {111}, respectively. The strong interaction between Au and CeO with the optimal crystal facet is crucial to adjust the active site density for activated O, and the synergy effect of Au and the CeO{110} facet possesses the largest density of active sites compared with other crystal facets of {100} and {111}. The catalytic activity for soot combustion was tuned by exposed crystal facets of CeO. The Au/CeO-rod catalyst exhibits the highest catalytic activity ( = 350 °C, TOF = 0.18 h) and the lowest apparent activation energy (72 kJ mol) during soot combustion. Based on the results of in situ Raman spectra, the formation and stability of oxygen vacancy located at the interface of the Au-O-Ce bond, boosting the key step of NO oxidation to NO, are dependent on the exposed crystal facets of CeO. It highlights a new strategy for the fabrication of high-efficient CeO-based catalysts for the removal of soot particles or other pollution.
优化催化剂的表面晶面是提高柴油烟尘催化净化效率的有效策略，烟尘是大气细颗粒物的重要组成部分。在此，我们精心构建了负载在具有明确{110}、{100}和{111}面优势暴露晶面的棒状、立方体和多面体 CeO 上的 Au 纳米颗粒纳米催化剂。Au 与 CeO 之间的强相互作用和最佳晶体面对于调节活性 O 的活性位点密度至关重要，与{100}和{111}等其他晶面相比，Au 和 CeO{110}面的协同效应具有最大的活性位点密度。CeO 的暴露晶面对烟尘燃烧的催化活性进行了调谐。在烟尘燃烧过程中，Au/CeO-rod 催化剂表现出最高的催化活性（T10 = 350°C，TOF = 0.18 h）和最低的表观活化能（72 kJ mol）。根据原位拉曼光谱的结果，位于 Au-O-Ce 键界面处的氧空位的形成和稳定性，促进了 NO 氧化为 NO 的关键步骤，这取决于 CeO 的暴露晶面。这为制备高效 CeO 基催化剂以去除烟尘颗粒或其他污染物提供了一种新策略。
