【摘要】 以Y(NO3)3为前驱体制备了Y2O3涂层的堇青石蜂窝陶瓷载体.扫描电子显微镜、X射线能谱和超声波振荡等表征结果表明,Y2O3涂层不但具有良好的抗振荡性和粘结强度,而且具有很强的吸附催化剂活性组分(H2PdCl4)的能力,适合制备负载型Pd催化剂.以甲苯和乙酸乙酯完全燃烧为模型反应考察了催化剂的活性,发现以Y2O3涂层堇青石蜂窝陶瓷为载体的整体式Pd/Y2O3催化剂具有良好的催化活性和热稳定性,甲苯和乙酸乙酯催化燃烧的T99分别为210和300℃;催化剂经900℃焙烧4 h后,T99仅提高20℃,表明催化剂具有很高的热稳定性.催化剂的X射线衍射、拉曼光谱和程序升温还原结果表明,Pd/Y2O3催化剂经低温焙烧时,Y2O3和PdO均高度分散在堇青石蜂窝陶瓷的表面,而高温焙烧使催化剂活性组分PdO晶粒增大,从而导致催化剂活性下降.更多还原

【Abstract】 A novel Y2O3 washcoat adhered to the cordierite honeycomb was prepared using Y(NO3)3 as the precursor.The Y2O3 washcoat is suitable for supported Pd catalysts.Catalytic combustion of toluene and ethyl acetate was conducted as model reactions to evaluate the performance of Pd/Y2O3 catalysts.The catalysts exhibit fairly good catalytic activity and thermal stability.For the catalysts calcined at 500 ℃,the T99 of toluene is 210 ℃.The Y2O3 washcoat and the Pd/Y2O3 catalysts were characterized by scanning electron microscopy,energy dispersive X-ray spectroscopy,X-ray diffraction,Raman spectroscopy,and H2-temperature-programmed reduction.The results show that the washcoat has sufficient adhesion and high adsorption efficiency for active species.For the catalysts calcined at higher temperatures(700 ℃ and 900 ℃),the crystallite size of the active species(PdO) increases,which possibly results in a decline in the catalytic activity.更多还原