Influence of ZnO Facets on Pd/ZnO Catalysts for Methanol Steam Reforming
Influence of ZnO Facets on Pd/ZnO Catalysts for Methanol Steam Reforming
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DOI：
10.1021/cs500590t
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发表时间：
2014-06
期刊：
影响因子：
12.9
通讯作者：
He Zhang;Junming Sun;V. Dagle;B. Halevi;A. Datye;Yong Wang
中科院分区：
文献类型：
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作者：
He Zhang;Junming Sun;V. Dagle;B. Halevi;A. Datye;Yong Wang
采用具有（10-10）个非极性晶面的针状ZnO微晶（ZnO-N）和没有任何主晶面的商品ZnO（ZnO-P）制备了一系列Pd/ZnO催化剂。Pd/ZnO催化剂的特征在于使用互补的技术，如氮气物理吸附，X射线衍射（XRD），高分辨率透射电子显微镜（HRTEM），和吸附CO的傅里叶变换红外光谱分析（CO-FTIR）。研究了ZnO微晶的小面化对Pd/ZnO催化剂甲醇水蒸气重整反应活性和选择性的影响。发现富Pd相（PdxZny，x > y）主要在两种ZnO载体（ZnO-N和ZnO-P）上在低Pd负载下形成，导致高CO选择性。随着Pd负载量的增加，PdxZny相中的x/y比降低，导致CO选择性降低。结果表明，Pd/ZnO-P催化剂具有更高的选择性，这是由于Pd/ZnO-N催化剂更容易形成活性中心，而Pd/ZnO-P催化剂具有更高的选择性。
A series of Pd/ZnO catalysts with different Pd loadings were prepared using needlelike ZnO crystallites (ZnO-N) with predominant (10–10) nonpolar facets exposed and commercial ZnO (ZnO-P) without any dominant facets. The Pd/ZnO catalysts were characterized using complementary techniques, such as nitrogen physisorption, X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and Fourier transform infrared spectroscopy analysis of adsorbed CO (CO-FTIR). The effect of ZnO crystallite faceting on the activity and selectivity of the Pd/ZnO catalysts was studied in methanol steam reforming (MSR). It was found that the Pd-rich phases (PdxZny, x > y) are predominantly formed at low Pd loadings on both ZnO supports (ZnO-N and ZnO-P), resulting in high CO selectivity. As Pd loading increases, the x/y ratio in the PdxZny phases decreases, leading to decreased CO selectivity. At similar Pd loadings, Pd/ZnO-P catalysts are more selective in MSR than Pd/ZnO-N, which is due to more facile form...