| Abstract: | A Pt-Rh three-way catalyst(M-DS) supported on CeO_2-ZrO_2-La_2O_3-Nd_2O_3 and its analogous supported catalyst(DS) were developed via a modified double-solvent method and conventional double-solvent method, respectively. The as-prepared catalysts were characterized by N_2 adsorption-desorption, X-ray diffraction(XRD), CO-chemisorption, X-ray photoelectron spectroscopy(XPS) and hydrogen temperature-programmed reduction(H_2-TPR). The preformed Pt nanoparticles generated using ethanol as a reducing agent on M-DS presented enhanced Pt dispersion regardless of aging treatment as confirmed by XRD and CO-chemisorption measurements. The textural properties and reduction ability of M-DS were maintained to a large extent after aging treatment. This result was consistent with those of the N_2 adsorption-desorption and H_2-TPR, respectively. Meanwhile, the XPS analysis demonstrated that higher Pt~0 species and larger Ce~(3+) concentration could be obtained for M-DS. In the conversion of a simulated compressed natural gas(CNG) vehicle exhaust, both fresh and aged M-DS showed a significant enhancement in the activity and N_2-selectivity. Particularly, the complete conversion temperature(T_(90)) of CH_4 over the aged M-DS catalyst was 65 oC lower than that over the aged catalyst by conventional double-solvent method. |
