Pd-Cu/carbon doped attapulgite catalyst and preparation method thereof

Abstract

The invention provides a Pd-Cu / carbon doped attapulgite catalyst and a preparation method thereof, wherein the preparation method comprises the preparation steps: weighing an appropriate amount of attapulgite, carbohydrates and ammonium chloride, mixing with distilled water at room temperature, stirring to form a suspension, and then carrying out heat treatment to prepare a carbon doped attapulgite carrier; and preparing an aqueous solution of palladium salt and copper salt, adding the carbon doped attapulgite carrier, adjusting the pH value of the system to be alkaline, and directly baking to obtain the catalyst finished product. The catalyst prepared by the method has wide applicable condition range, can efficiently catalyze oxidation of CO under reaction conditions of the reaction temperature of -70 to 150 DEG C, the air speed of 2000-20000 h<-1>, the CO content of 10-15000 ppm and the raw material gas relative humidity of 20%-100%, and allows a deactivated catalyst to be easy to regenerate. The catalyst preparation method has the advantages of simple process, easy operation, low cost and good application prospect.

Description

technical field [0001] The invention relates to a catalyst for low-temperature oxidation of carbon monoxide, in particular to a Pd-Cu / carbon-doped attapulgite catalyst and a preparation method thereof which can be used under the condition of high-concentration water vapor. Background technique [0002] Low-temperature catalytic oxidation of CO is widely used in environmental protection, industry, military and human life, such as filter self-rescuer and fire self-rescue respirator, CO gas sensor, motor vehicle cold start exhaust control, fuel cell, closed internal circulation CO 2 Lasers, tobacco damage reduction, and trace CO elimination in closed systems (such as: submarines, spacecraft, etc.). However, under the conditions of low temperature and high concentration of water vapor, many catalysts have the problems of low activity and poor stability. Therefore, the study of catalysts with high activity and high stability under low temperature and high concentration of water ...

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Problems solved by technology

But since Al 2 o 3 The carrier has strong hydrophilicity, and the water vapor molecules in the raw material gas are continuously adsorbed and condensed on the surface of the catalyst during the long-term reaction process under the condition of water vapor, and the water molecules covering the active center are difficult to desorb, and can further induce Cu Species active phase Cu 2 (OH) 3 Cl grains aggregate and grow or phase transform into CuCl, which weakens the interaction between Pd and Cu, inhibits the reoxidation ability of low-valence Pd species on the catalyst surface, hinders the redox cycle, and leads to irreversible deactivation of the catalyst (Feng Yafen, Wang Li, Zhang Yanhui, Guo Yun, Guo Yanglong, Lu Guanzhong, Chinese Journal of Catalysis, 2013, 34:923-931)

Using natural attapulgite clay (APT) as a carrier, our research group has successively studied the design and preparation of Pd-Cu bimetallic catalysts with low noble metal content (Wang Yongzhao, Zhang Zhuo, Zhao Yongxiang, Li Fengmei. Industrial Catalysis, 2011,19:74- 79), the effect of calcination treatment, preparation method and carrier modification on the catalytic CO oxidation performance of Pd-Cu / APT (Wang Yongzhao, Cheng Huimin, Fan Liyuan, Shi Jing, Zhao Yongxiang. Journal of Fuel Chemistry, 2014,42(5):597~602 ; Yongzhao Wang, Jing Shi, Ruifang Wu, Xiao Li, Yongxiang Zhao, Applied ClayScience, 2016, 119:126-131; Yongzhao Wang, Liyuan Fan, Jing Shi, Xiao Li, Yongxiang Zhao, Catal Lett, 2015, 145: 1429- 1435; WANG Yong-zhao, FAN Li-yuan, WU Rui-fang, SHIJing, LI Xiao, ZHAO Yong-xiang, Journal of Fuel Chemistry and Technology, 2015,43(9):1076-1082; Chinese invention patent CN 103464170B ), it was found that the Pd-Cu / APT catalyst supported by attapulgite clay had high CO catalytic oxidation performance under normal temperature and humidity conditions, but there were problems such as low activity and poor stability under high concentration water vapor conditions