本文選題：Cu-Ce-Zr催化劑 + 催化氧化��； 參考：《天津科技大學》2017年碩士論文

【摘要】：揮發(fā)性有機物(VOCs)是造成嚴重灰霾天氣的先導因子,給人體健康和環(huán)境帶來巨大的危害。催化氧化法是有效降解揮發(fā)性有機物的方法之一,而催化劑性能的優(yōu)劣直接決定著催化降解的效率和運行成本的高低。本文采用不同方法制備了復合氧化物催化劑CuCe0.75Zr0.25Oy和負載型催化劑CuCe0.75Zr0.25Oy/H-ZSM-5,通過 N2低溫物理吸脫附、XRD、H2-TPR、NH3-TPD、02-TPD和Raman等手段對催化劑的物理化學等性質進行了表征,以甲苯和/或乙酸乙酯為VOCs目標污染物,在固定床反應器上評價了催化劑的性能,實驗結果如下:(1)制備方法對催化劑性能的影響:采用溶膠-凝膠法、熱分解法和固相反應法以及浸漬法分別制備了CuCe0.75Zr0.25Oy和CuCe0.75Zr0.25Oy/H-ZSM-5催化劑。結果表明,比表面積是影響負載型催化劑降解VOCs性能的重要因素之一,而比表面積對復合氧化物催化劑活性的影響并不明顯。催化劑中體相CuO的存在,減弱了 CuO與Ce02之間的相互作用,降低了催化劑的反應活性。溶膠-凝膠法制備的CuCe0.75Zr0.25Oy催化劑的活性明顯高于其它方法制備的催化劑,該催化劑較好的低溫還原性和豐富的晶格氧促進了甲苯的催化降解反應,而大的孔徑又有利于反應物和產(chǎn)物遷移和擴散,使其T1o (137℃)、T50 (183℃)和T90 (260℃)明顯低于其它催化劑;在高溫(300℃)72 h的穩(wěn)定性實驗中,未發(fā)現(xiàn)失活現(xiàn)象。(2)造孔劑對溶膠-凝膠法制備催化劑性能的影響:通過考察生物基造孔劑細菌纖維素(BC)和化學造孔劑草酸、檸檬酸以及草酸與乙二醇和環(huán)己烷混合液對溶膠-凝膠法制備催化劑性能的影響,得到采用生物基造孔劑BC制備的CuCe0.75Zr0.25Oy催化劑呈現(xiàn)出了最好的催化劑活性,甲苯轉化率達到100%時的轉化溫度僅為220℃,明顯低于其它催化劑,多級孔結構和高的相對氧空位濃度是催化劑具有高活性的主要原因。(3)細菌纖維素類型對CuCe0.75Zr0.25Oy催化劑性質的影響:以商品BC為造孔劑制備的催化劑(Com-BC)的活性明顯高于以培養(yǎng)BC為造孔劑制備的催化劑(Cul-BC),Com-BC催化降解甲苯和乙酸乙酯的完全轉化溫度分別為220℃和170℃,分別比Cul-BC的低20℃和30℃,在甲苯和乙酸乙酯完全轉化溫度下對Com-BC進行的100h穩(wěn)定性實驗過程中,未發(fā)現(xiàn)失活現(xiàn)象。這主要是由于Com-BC催化劑具有微孔、介孔和大孔的多級孔結構,以及CuO在催化劑表面較好的分散性和較小的晶粒尺寸造成的。
[Abstract]:Volatile organic compounds (VOCs) are the leading factors causing severe haze weather, which bring great harm to human health and environment. Catalytic oxidation is one of the effective methods for the degradation of volatile organic compounds (VOCs), and the performance of the catalysts directly determines the efficiency and operation cost of catalytic degradation. In this paper, composite oxide catalyst CuCe0.75Zr0.25Oy and supported catalyst CuCe0.75Zr0.25Oy / H-ZSM-5 were prepared by different methods. The physicochemical properties of the catalysts were characterized by physical desorption and desorption of XRDX H2-TPRN NH3-TPD02-TPD and Raman at low temperature. Using toluene and / or ethyl acetate as the target pollutants of VOCs, the performance of the catalyst was evaluated in a fixed-bed reactor. The experimental results are as follows: the effect of preparation method on the performance of the catalyst is as follows: Sol-gel method is used. CuCe0.75Zr0.25Oy and CuCe0.75Zr0.25Oy / H-ZSM-5 catalysts were prepared by thermal decomposition, solid state reaction and impregnation, respectively. The results show that the specific surface area is one of the important factors affecting the catalytic performance of the supported catalysts for VOCs degradation, but the specific surface area has no obvious effect on the activity of the composite oxide catalysts. The presence of CuO in the catalyst weakens the interaction between CuO and Ce02 and decreases the catalytic activity of the catalyst. The activity of CuCe0.75Zr0.25Oy catalyst prepared by sol-gel method was obviously higher than that prepared by other methods. The catalytic degradation of toluene was promoted by the catalyst with good low temperature reductivity and abundant lattice oxygen. However, the large pore size is beneficial to the migration and diffusion of reactants and products, which makes the T1O ~ (137 鈩，

本文編號：2000504