以水热法合成的ZrO_2负载Au催化剂上的低温水煤气变换反应

采用一种简便的水热法合成了一系列ZrO2,并采用沉积-沉淀法制得相应1.0%Au/ZrO2催化剂,在模拟甲醇重整气气氛下评价了它们的低温水煤气变换(WGS)反应催化性能.结果发现,于150oC水热合成的ZrO2负载的Au催化剂活性最佳,240oC反应时CO转化率达87%,明显高于相同反应条件下Au负载量较高的Au/Fe2O3,Au/CeO2及Au/CeZrO4催化剂.采用X射线衍射、原子吸收光谱、N2物理吸脱附及扫描电子显微镜等手段对样品进行了表征.结果表明,Au/ZrO2催化剂的总孔体积及平均孔径越大、圆形片状形貌越规整,其低温WGS催化活性就越高.

Low-Temperature Water-Gas Shift Reaction over Au/ZrO2 Catalysts Using Hydrothermally Synthesized Zirconia as Supports

Au/ZrO2 catalysts with a nominal gold loading of 1.0% were prepared by a deposition-precipitation method employing a series of ZrO2 samples synthesized by a convenient hydrothermal route as supports.These catalysts were evaluated for low-temperature water-gas shift reaction under a model reformed methanol gas atmosphere.The effect of the hydrothermal synthesis temperature of zirconia on the catalytic activity of Au/ZrO2 was investigated.The optimal hydrothermal synthesis temperature of ZrO2 was 150 °C.The corresponding catalyst offers a CO conversion of 87% at a reaction temperature of 240 °C,which is significantly higher than that of the previously reported Au/Fe2O3,Au/CeO2,and Au/CeZrO4 catalysts.The Au/ZrO2 catalysts were characterized by X-ray diffraction,atomic absorption spectrometry,N2-physisorption,and scanning electron microscopy.The results indicate that the catalytic performance of the Au/ZrO2 catalysts is mainly influenced by the morphology and pore structure of the ZrO2 that was hydrothermally synthesized at different temperatures.A uniform nanodisk morphology and increase in the pore volume and pore diameter of the ZrO2 particles lead to a higher catalytic activity of the Au/ZrO2 catalyst.