The 0.7 wt% Pt ＋ 0.3 wt% Rh/Ce0.6Zr0.4O2 catalysts were fabricated via different methods, including ultrasonic-assisted membrane reduction （UAMR） co-precipitation, UAMR separation precipitation, co-impregnation, an...The 0.7 wt% Pt ＋ 0.3 wt% Rh/Ce0.6Zr0.4O2 catalysts were fabricated via different methods, including ultrasonic-assisted membrane reduction （UAMR） co-precipitation, UAMR separation precipitation, co-impregnation, and sequential impregnation. The catalysts were physico-chemically characterized by N2 adsorption, XRD, TEM, and Hz-TPR techniques, and evaluated for three-way catalytic activities with simulated automobile exhaust. UAMR co-precipitation- and UAMR separation precipitation- prepared catalysts exhibited a high surface area and metal dispersion, wide λ window and excellent conversion for NOx reduction under lean conditions. Both fresh and aged catalysts from UAMR- precipitation showed the high surface areas of ca. 60-67 m^2/g and 18-22 m^2/g, respectively, high metal dispersion of 41%-55%, and small active particle diameters of 2.1-2.7 nm. When these catalysts were aged, the catalysts prepared by the UAMR method exhibited a wider working window （△λ = 0.284--0.287） than impregnated ones （△λ = 0.065-0.115） as well as excellent three-way catalytic performance, and showed lower/so （169℃） and T90 （195℃） for NO reduction than the aged catalysts from impregnation processes, which were at 265 and 309℃, respectively. This implied that the UAMR-separation precipitation has important potential for industrial applications to improve catalytic performance and thermal stability. The fresh and aged 0.7 wt% Pt ＋ 0.3 wt% Rh/Ce0.6Zr0.4O2 catalysts prepared by the UAMR-separation precipitation method exhibited better catalytic performance than the corresponding catalysts prepared by conventional impregnation routes.展开更多
基金supported by the National Nature Foundation of China(No.21277009)the Beijing National Nature Foundation(No.2101002)+2 种基金the Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality(No.PHR201107104,PHR200907105)the National Research and Development Program(863)of China(No.2011AA03A406)the National Industrial Project of New Rare Earth Materials
文摘The 0.7 wt% Pt ＋ 0.3 wt% Rh/Ce0.6Zr0.4O2 catalysts were fabricated via different methods, including ultrasonic-assisted membrane reduction （UAMR） co-precipitation, UAMR separation precipitation, co-impregnation, and sequential impregnation. The catalysts were physico-chemically characterized by N2 adsorption, XRD, TEM, and Hz-TPR techniques, and evaluated for three-way catalytic activities with simulated automobile exhaust. UAMR co-precipitation- and UAMR separation precipitation- prepared catalysts exhibited a high surface area and metal dispersion, wide λ window and excellent conversion for NOx reduction under lean conditions. Both fresh and aged catalysts from UAMR- precipitation showed the high surface areas of ca. 60-67 m^2/g and 18-22 m^2/g, respectively, high metal dispersion of 41%-55%, and small active particle diameters of 2.1-2.7 nm. When these catalysts were aged, the catalysts prepared by the UAMR method exhibited a wider working window （△λ = 0.284--0.287） than impregnated ones （△λ = 0.065-0.115） as well as excellent three-way catalytic performance, and showed lower/so （169℃） and T90 （195℃） for NO reduction than the aged catalysts from impregnation processes, which were at 265 and 309℃, respectively. This implied that the UAMR-separation precipitation has important potential for industrial applications to improve catalytic performance and thermal stability. The fresh and aged 0.7 wt% Pt ＋ 0.3 wt% Rh/Ce0.6Zr0.4O2 catalysts prepared by the UAMR-separation precipitation method exhibited better catalytic performance than the corresponding catalysts prepared by conventional impregnation routes.
