The action of VOx doping on Au/CeO2 catalysts for CO oxidation and water–gas shift reaction
The action of VOx doping on Au/CeO2 catalysts for CO oxidation and water–gas shift reaction
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DOI：
10.1007/s11144-015-0921-5
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发表时间：
2015-08
期刊：
影响因子：
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通讯作者：
Wei-ping Liao;Hongying Lv;Zhang Suo
中科院分区：
文献类型：
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作者：
Wei-ping Liao;Hongying Lv;Zhang Suo
采用溶液燃烧合成法制备了不同Ce/V摩尔比的VOx-CeO2氧化物。采用浸渍法制备了用于CO氧化和水煤气变换反应的Au/VOx-CeO2催化剂。采用氮气物理吸附、X射线衍射、紫外-可见光谱、程序升温还原和X射线光电子能谱等技术对材料的织构性质和结构进行了研究。得到如下活性顺序：Au/CeO2~Ce9V1；Au/Ce7V3；Au/Ce7V3；Au/Ce5V5；Au/Ce9V1；Cau/Ce7V3；Cat；Au/Ce9V1；Cat；Au/Ce7V3；Cat；Au/Ce7V3；&Gt；Au/Ce7V3；Au/Ce5V5；WGSR在350℃时比WGSR更容易氧化。Vox值较低的催化剂表现出较好的活性。在CeO2中加入高含量的VOxor会导致聚合VOxor聚钒物种的团聚。这些物种使CeO2的还原变得更加困难，金与CeO2之间的相互作用较弱。Au的存在有效地促进了CeO2向较低温度的还原。金、VOx和CeO2之间的相互作用有利于提高Au/VOx-CeO2催化剂的活性。
VOx–CeO2oxides with different Ce/V molar ratios were prepared via solution combustion synthesis method. Au/VOx–CeO2catalysts were obtained by the impregnation method for CO oxidation and water–gas shift reaction (WGSR). The textural properties and structures of these materials were investigated by the techniques such as nitrogen physical adsorption, X-ray diffraction, UV–Visible spectroscopy, temperature-programmed reduction, and X-ray photoelectron spectroscopy. The following activity orders are obtained: Au/CeO2~ Au/Ce9V1 > Au/Ce7V3 > Au/Ce5V5 for CO oxidation at 20 °C and Au/Ce9V1 > Au/CeO2> Au/Ce7V3 > Au/Ce5V5 for WGSR at 350 °C. CO oxidation proceeds more easily than WGSR at the same catalyst. The catalysts with low VOxcontent show better activities. The addition of high VOxcontent to CeO2leads to the agglomeration of polymeric VOxor polyvanadate species. These species make the reduction of CeO2more difficult and the interaction between gold and CeO2weak. The presence of Au effectively enhances the reduction of CeO2to lower temperatures. The interaction between gold, VOx, and CeO2is favorable to improving the activity of Au/VOx–CeO2catalyst.