Influence of Al2O3/CeZrAl composition on the catalytic behavior of Pd/Rh catalyst

Al2O3 and Ce-Zr mixed oxides are important components of the automobile three-way catalyst.Various contents modifying A12O3(GAL) was physically introduced into Ce-Zr-Al mixed oxides(CZA) to form series of GAL/CZA composition.The Pd/Rh catalyst samples were prepared by different GAL/CZA support loading Pd/Rh,then aged at 950 oC for 6 h.The catalytic behavior of different Pd/Rh catalyst samples was studied.Surface area,oxygen storage capacity(OSC) and H2 adsorption capacity(TPR) of fresh and aged samples were examined by means of BET and H2-TPR.The analysis results of surface area and chemical absorption reduction showed that GAL content in GAL/CZA composition was the main effect on surface area stability of Pd/Rh catalyst.Compared with pure CZA,CZA by mixing physically with GAL could promote the surface area and stability of Pd/Rh catalyst.On the other hand,higher OSC and OSC stability should depend on CZA content in GAL/CZA composition.Compared with pure GAL,higher CZA content in GAL/CZA can promote the OSC and OSC stability of Pd/Rh catalyst.TPR showed that the optimal range of composition(CZA>60%) could obtain high reduction activity.GAL and CZA had a synergistic effect on the surface area and OSC of catalyst.The suitable mixing ratio of GAL and CZA in GAL/CZA could simultaneously get more surface area and OSC to make better catalytic activity of Pd/Rh catalyst.