Crystal-Plane-Controlled Surface Chemistry and Catalytic Performance of Surfactant-Free Cu2O Nanocrystals
Crystal-Plane-Controlled Surface Chemistry and Catalytic Performance of Surfactant-Free Cu2O Nanocrystals
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无表面活性剂 Cu2O 纳米晶体的晶面控制表面化学和催化性能。
DOI：
10.1002/cssc.201300376
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发表时间：
2013-10-01
期刊：
影响因子：
8.4
通讯作者：
Huang, Weixin
中科院分区：
文献类型：
--
作者：
Hua, Qing;Cao, Tian;Huang, Weixin
以无表面活性剂的Cu 2 O纳米晶（包括暴露{100}晶面的立方体、暴露{111}晶面的八面体和暴露{110}晶面的菱形十二面体）为模型催化剂，研究了晶面对Cu 2 O纳米晶表面化学和CO氧化催化性能的影响.催化性能的顺序为八面体菱形十二面体>立方体，这表明在Cu 2 O（111），（110）和（100）表面中，Cu 2 O（111）表面对CO氧化的催化活性最高. CO程序升温还原结果表明，Cu 2 O八面体是Cu 2 O立方体、八面体和菱形十二面体中最容易还原的。漫反射红外光谱表明CO在Cu 2 O纳米晶上的化学吸附取决于其形状和化学吸附温度。在30°C下，CO在菱形十二面体上的化学吸附最强，但在150°C下在八面体上最强。各种Cu 2 O纳米晶对CO的还原和化学吸附能力与其催化CO氧化的性能一致。所观察到的表面化学和各种Cu 2 O纳米晶体在CO氧化中的催化性能可以很好地与它们暴露的晶面和表面组成/结构相关。Cu 2 O八面体暴露出具有配位的不饱和Cu（I）位点的{111}晶面，因此在化学吸附CO和催化CO氧化中最活跃。这些结果很好地证明了氧化物催化剂的晶面控制的表面化学和催化性能。
Surfactant-free Cu2 O nanocrystals, including cubes exposing {100} crystal planes, octahedra exposing {111} crystal planes, and rhombic dodecahedra exposing {110} crystal planes, were used as model catalysts to study the effect of the crystal plane on the surface chemistry and catalytic performance for CO oxidation of Cu2 O nanocrystals. The catalytic performance follows the order of octahedra rhombic dodecahedra>cubes; this suggests that Cu2 O(111) is most active in catalyzing CO oxidation among Cu2 O (111), (110), and (100) surfaces. CO temperature-programmed reduction results demonstrate that Cu2 O octahedra are the most easily reduced of the Cu2 O cubes, octahedra, and rhombic dodecahedra. Diffuse reflectance FTIR spectra show that CO chemisorption on Cu2 O nanocrystals depends on their shape and the chemisorption temperature. CO chemisorption is strongest on rhombic dodecahedra at 30°C, but at 150°C on octahedra. Both the reducibility and chemisorption ability of various Cu2 O nanocrystals toward CO are consistent with their catalytic performance in CO oxidation. The observed surface chemistry and catalytic performance in CO oxidation of various Cu2 O nanocrystals can be well correlated with their exposed crystal plane and surface composition/structure. Cu2 O octahedra expose the {111} crystal plane with coordinated, unsaturated Cu(I) sites, and thus, are most active in chemisorbing CO and catalyzing CO oxidation. These results nicely demonstrate the crystal-plane-controlled surface chemistry and catalytic performance of oxide catalysts.