Catalytic combustion of toluene over Pd-based monolithic catalysts with a novel washcoat Ce_(0.8)Zr_(0.15)La_(0.05)O_δ
来源期刊：JOURNAL OF RARE EARTHS2009年第5期
论文作者：ZHANG Qingbao YUE Lei LUO Mengfei ZHANG Tian ZHAO Leihong
Key words：toluene combustion; monolithic catalyst; volatile organic compounds; CeO2-ZrO2; La3+; rare earths;
Abstract: Two novel washcoats Ce_(0.8)Zr_(0.15)La_(0.05)O_δ and Ce_(0.5)Zr_(0.2)O_2 was prepared by an impregnation method, which acted as a host for the active Pd component to prepare Pd/Ce_(0.8)Zr_(0.15)La_(0.05)O_δ/substrate and Pd/Ce_(0.5)Zr_(0.2)O_2/substrate monolithic catalysts for toluene combustion.The washcoats was characterized by X-ray diffraction (XRD), Raman spectroscopy, Brunauner-Emmett-Teller (BET), and H_2-temperature-programmed reduction (H2-TPR). The result indicated that both the washcoats had strong vibration-shock resistance accord-hag to ultrasonic test. Doping La3+ into CeO_2-ZrO_2 solid solution could generate more oxygen vacancies, and could inhibit the sinter of CeO_2-ZrO_2 solid solution when calcined at high temperatures (800, 900 and 1000 ℃). The washcoat Ce_(0.8)Zr_(0.15)La_(0.05)O_δ had much better re-dox properties. The reductive temperature of Ce~(4+) species shifted to low temperature by 60℃ when the washcoats calcined at high tempera-tures (800, 900 and 1000 ℃). The Pd/Ce_(0.8)Zr_(0.15)La_(0.05)O_δ/substrate monolithic catalyst calcination at 500℃ had the best catalytic activity and the 95% toluene conversion at a temperature as low as 190℃. When calcined at low temperature (500 and 700 ℃), the catalytic activity has little improvement, however, when calcined at high temperature, the catalytic activity of Pd/Ce_(0.8)Zr_(0.15)La_(0.05)O_δ/substrate monolithic catalysts had significant improvement. As catalyst washcoat, the Ce_(0.5)Zr_(0.15)La_(0.05)O_δ had better thermal stability than the washcoat Ce_(0.8)Zr_(0.2)O_2 the de-veloped Pd/Ce_(0.8)Zr_(0.15)La_(0.05)O_δ/substrate monolithic catalyst in this work was promising for eliminating Volatile organic compounds.
ZHANG Qingbao1，YUE Lei1，LUO Mengfei1，ZHANG Tian1，ZHAO Leihong1
(1.Zhejiang Key Laboratory for Reactive Chemistry on Solid Surface, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004, China)
Abstract:Two novel washcoats Ce_(0.8)Zr_(0.15)La_(0.05)O_δ and Ce_(0.5)Zr_(0.2)O_2 was prepared by an impregnation method, which acted as a host for the active Pd component to prepare Pd/Ce_(0.8)Zr_(0.15)La_(0.05)O_δ/substrate and Pd/Ce_(0.5)Zr_(0.2)O_2/substrate monolithic catalysts for toluene combustion.The washcoats was characterized by X-ray diffraction (XRD), Raman spectroscopy, Brunauner-Emmett-Teller (BET), and H_2-temperature-programmed reduction (H2-TPR). The result indicated that both the washcoats had strong vibration-shock resistance accord-hag to ultrasonic test. Doping La3+ into CeO_2-ZrO_2 solid solution could generate more oxygen vacancies, and could inhibit the sinter of CeO_2-ZrO_2 solid solution when calcined at high temperatures (800, 900 and 1000 ℃). The washcoat Ce_(0.8)Zr_(0.15)La_(0.05)O_δ had much better re-dox properties. The reductive temperature of Ce~(4+) species shifted to low temperature by 60℃ when the washcoats calcined at high tempera-tures (800, 900 and 1000 ℃). The Pd/Ce_(0.8)Zr_(0.15)La_(0.05)O_δ/substrate monolithic catalyst calcination at 500℃ had the best catalytic activity and the 95% toluene conversion at a temperature as low as 190℃. When calcined at low temperature (500 and 700 ℃), the catalytic activity has little improvement, however, when calcined at high temperature, the catalytic activity of Pd/Ce_(0.8)Zr_(0.15)La_(0.05)O_δ/substrate monolithic catalysts had significant improvement. As catalyst washcoat, the Ce_(0.5)Zr_(0.15)La_(0.05)O_δ had better thermal stability than the washcoat Ce_(0.8)Zr_(0.2)O_2 the de-veloped Pd/Ce_(0.8)Zr_(0.15)La_(0.05)O_δ/substrate monolithic catalyst in this work was promising for eliminating Volatile organic compounds.
Key words:toluene combustion; monolithic catalyst; volatile organic compounds; CeO2-ZrO2; La3+; rare earths;
【全文内容正在添加中】
