摘要
Pd-only three-way catalyst （TWC）, Pd supported on washcoating （the mixture of alumina and Ce-Zr solid solution）/cordierite, was prepared and its catalytic performance and the operation window （2-value） at 450 ℃ were evaluated with the simulated automotive exhaust feed gas. Surfactants such as Tween-80 and Span-20 were added in the process of preparing the catalyst in order to improve the thermal stability and catalytic performance of Pd-only TWC. The fresh and aged catalysts at 1000 ℃ for 4 h were characterized by low-temperature N2 adsorption, XRD, XPS, and H2-TPR techniques. The results show that the presence of surfactants in the synthesis slurry could influence the physicochemical properties of the final Pd-only TWC. The FTS catalyst prepared with the mixed surfactant of Tween-80 and Span-20 exhibited excellent three-way catalytic performance. After being aged at 1000℃ for 4 h, the catalytic performances of Pd-only TWCs slightly decreased, but the FTS catalyst still demonstrated higher catalytic performance and better thermal stability compared with the Pd-only catalysts prepared with single surfactant or without any surfactant. And the FTS catalyst has a wider 2 value （operation window） than other catalysts, even after being aged at 1000℃.
Pd-only three-way catalyst(TWC),Pd supported on washcoating(the mixture of alumina and Ce-Zr solid solution)/cordierite,was prepared and its catalytic performance and the operation window(λ-value)at 450°C were evaluated with the simulated automotive exhaust feed gas.Surfactants such as Tween-80 and Span-20 were added in the process of preparing the catalyst in order to improve the thermal stability and catalytic performance of Pd-only TWC.The fresh and aged catalysts at 1000°C for4 h were characterized by low-temperature N2 adsorption,XRD,XPS,and H2-TPR techniques.The results show that the presence of surfactants in the synthesis slurry could influence the physicochemical properties of the final Pd-only TWC.The FTS catalyst prepared with the mixed surfactant of Tween-80 and Span-20 exhibited excellent three-way catalytic performance.After being aged at 1000°C for 4 h,the catalytic performances of Pd-only TWCs slightly decreased,but the FTS catalyst still demonstrated higher catalytic performance and better thermal stability compared with the Pd-only catalysts prepared with single surfactant or without any surfactant.And the FTS catalyst has a widerλvalue(operation window)than other catalysts,even after being aged at 1000°C.
基金
financially supported by the National Basic Research Program of China(2010CB732300)
the National Natural Science Foundation of China(21273150)
the National High Technology Research and Development Program of China(2011AA03A406)
