High Temperature Interaction of Rhodium with Oxygen Storage Component in Three-Way Catalysts

摘要

A series of three-way catalysts with Rh loading in the range of 0.01-1 wt% was prepared by incipient wetness impregnation. CeO2, CeZrO2 and ZrCeYLaO2 were used as a support. All samples were tested for catalytic activity and oxygen storage capacity function, and characterized by X-ray diffraction, surface area measurements, scanning and transmission electron microscopy, and ethane hydrogenolysis testing reaction. Rhodium was found to be in a strong interaction with ceria resulting in accelerated structure collapse at high temperatures. Ceria doped with Zr or Zr, Y and La has a minimal effect of Rh on textural changes. In all cases, surface concentration of Rh decreases in more than one order of magnitude. No phase transformation of oxygen storage component was detected by X-ray diffraction. The Rh-ceria particles with increased density were found regardless of type of the support. Coefficient of compaction for the Rh-containing catalysts diminishes in the following order: CeO2 > CeZrO2 > ZrCeYLaO2.