Formation and Characterization of PdZn Alloy: A Very Selective Catalyst for Alkyne Semihydrogenation
Formation and Characterization of PdZn Alloy: A Very Selective Catalyst for Alkyne Semihydrogenation
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DOI：
10.1021/jp1103164
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发表时间：
2011-05-05
影响因子：
3.7
通讯作者：
van Bokhoven, Jeroen A.
中科院分区：
文献类型：
--
作者：
Tew, Min Wei;Emerich, Herman;van Bokhoven, Jeroen A.
采用原位高分辨X射线衍射（HRXRD）和X射线吸收光谱（XAS）相结合的方法，对4.3%Pd/ZnO催化剂上PdZn合金的形成过程进行了表征。合金形成已经在大约100 ℃开始，可能在表面，并随着温度的升高而达到本体。在300 ℃及以上还原后，催化剂的结构接近于具有L1（o）结构的1：1 PdZn合金的体相值（R（Pd-Pd）= 2.9埃，R（Pd-zn）= 2.6埃，CN（Pd-zn）= 8，CN（Pd-Pd）=4）。PdZn合金的形成降低了1-戊炔气相加氢的活性。与Pd/SiO（2）相比，Pd/ZnO催化剂上没有发生完全氢化。随着时间的推移，在反应条件下仅发生合金的轻微分解。
The formation of a PdZn alloy from a 4.3% Pd/ZnO catalyst was characterized by combined in situ high-resolution X-ray diffraction (HRXRD) and X-ray absorption spectroscopy (XAS). Alloy formation started already at around 100 C, likely at the surface, and reached the bulk with increasing temperature. The structure of the catalyst was close to the bulk value of a 1:1 PdZn alloy with a L1(o) structure (R(Pd-Pd) = 2.9 angstrom, R(Pd-zn) = 2.6 angstrom, CN(Pd-zn)= 8, CN(Pd-Pd) =4) after reduction at 300 degrees C and above. The activity of the gas-phase hydrogenation of 1-pentyne decreased with the formation of the PdZn alloy. In contrast to Pd/SiO(2), no full hydrogenation occurred over Pd/ZnO. Over time, only slight decomposition of the alloy occurred under reaction conditions.