Abstract：To investigate the influence of defect structures in CeZrOx catalysts, which induced by rare earth metal doping, on the control of automotive exhaust pollution, series of Ni~(Ce6Zr4-xPrx)O2/Al2O3 catalysts with varied Pr doping content were synthesized, and their TWC activities and SO2 resistance performance were tested. The prepared catalysts were also systematically characterized. The collected results suggested that two kinds of defects in Ni~(Ce-Zr)O2/Al2O3 were generated after Pr doping, including oxygen vacancies (Ov) and lattice distortion, whose types and concentrations depended on the Pr doping content. The results also indicated that Ov play a vital role on the catalytic performance, whereas lattice distortion play a small effect on it. In addition, it is found that the concentrations of Ov in as-prepared catalysts determined their TWC catalytic performance, the Ni~(Ce6Zr3Pr1)O2/Al2O3 catalyst with most Ov concentrations performed superior three-way catalytic performance at 200~600℃ and also exhibited excellent anti-sulfur poisoning performance after introducing 100ppm SO2 at 600℃. This is because Ov not only promoted the dispersion of NiO, accelerating the migration and diffusion of bulk oxygen to form active oxygen species, thus promoting the adsorption and oxidation of CO and HC species on the catalyst, but also the Ov can weaken the N-O bonds boosting the dissociative adsorption and reduction of NO species.
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