Synthesis and Characterization of Ce_(0.5)Zr_(0.5)O_2 Nanocomposite and Its Supported Pd-Only Catalysis Activity

摘要

The Ce_(0.5)Zr_(0.5)O_2 nanocomposites (CZ) were prepared by co-precipitation(CP), fractional precipitation (FP) and fractional precipitation with hydrothermal treatment (FP-HT). The samples were characterized by X-ray diffraction (XRD), Brunauer-Emmet Teller method (BET), H_2-temperature programmed reduction (H_2-TPR), and thermogravimetric analysis (TG) under H_2-N_2. XRD results displayed that all samples formed a single solid solution-like ceria-zirconia phase. BET results revealed CZ prepared by FP-HT (CZ-FP-HT) had the highest surface area. H_2-TPR and TG analysis under H_2-N_2 showed CZ-FP-HT exhibited the strongest redox ability and oxygen storage capacity. Moreover, the catalytic activity of Pd supported on CZs for CH compounds were studied. The fresh and aged Pd/CZ-FP-HT catalyst all showed a lower light-off temperature and full-conversion temperture than Pd /CZ-CP and Pd/CZ-FP catalysts.