本文選題：水滑石　切入點：復(fù)合氧化物　出處：《中國科學(xué)院大學(xué)(中國科學(xué)院過程工程研究所)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：全國環(huán)境污染形勢越來越嚴重,解決環(huán)境問題迫在眉睫。揮發(fā)性有機化合物(Volatile organic compounds,VOCs)作為大氣污染物之一,不僅破壞生態(tài)環(huán)境,而且影響了人們的健康。催化氧化技術(shù)是解決空氣VOCs污染問題最有效途徑之一,且不會產(chǎn)生二次污染物,其關(guān)鍵問題是研制低成本、高效、穩(wěn)定性好的催化劑。水滑石(Layered Double Hydroxides,LDHs)衍生得到的復(fù)合氧化物具有多孔性、高比表面積、協(xié)同效應(yīng)、酸堿雙功能性及晶粒高度分散等特性,在環(huán)境催化領(lǐng)域表現(xiàn)出良好的應(yīng)用潛力,是制備催化反應(yīng)器的主要功能組件,尤其是整體式薄膜材料。本論文旨在通過制備含Co/Mn的LDHs衍生得到多元復(fù)合氧化物催化劑,詳細研究了其形貌、表面結(jié)構(gòu)和化學(xué)性質(zhì),揭示了催化劑結(jié)構(gòu)與催化氧化性能之間的關(guān)系;最終通過原位生長法制備ab面垂直于基底整體式薄膜催化劑。具體研究內(nèi)容和結(jié)果如下:(1)Co-Al復(fù)合氧化物的結(jié)構(gòu)調(diào)控及其催化氧化VOCs性能通過簡單地控制反應(yīng)溶劑(水、甲醇和乙醇)和氨釋放劑(氨水、六次甲基四胺和尿素)合成了不同形貌的Co-Al LDHs,包括彎曲片、不完整六邊形片和絨球狀,比較了其氧化物對典型VOCs(苯)催化氧化性能。結(jié)果表明,采用乙醇和尿素的條件所得的絨球狀的CoAl氧化物催化性能最好,在230℃下苯的轉(zhuǎn)化率為99%。(2)氧化物結(jié)構(gòu)缺陷及其催化氧化VOCs性能在純氧氣氣氛下,將Co2+(3d7)氧化為Co3+(3d6)成功制備了CoⅡCoⅢLDHs,煅燒后得到缺陷結(jié)構(gòu)氧化物。通過激光拉曼光譜、H2-TPR、TPD和XPS表征氧化物結(jié)構(gòu)缺陷(酸性位點、氧缺陷和表面價態(tài)分布),并與Co-Al氧化物比較對苯和甲苯的催化性能。原位氧化法制備的氧化物催化氧化苯、甲苯完全轉(zhuǎn)化的溫度分別為210℃和220℃,具有豐富的結(jié)構(gòu)缺陷,誘導(dǎo)產(chǎn)生良好的低溫還原性、表面路易斯酸性位點和活性氧(Oads)。(3)復(fù)合組分協(xié)同效應(yīng)與催化氧化性能關(guān)系通過分別引入Co、Ce摻雜Mn-Al LDHs成功制備了三元的LDHs,經(jīng)煅燒形成一系列層狀復(fù)合氧化物。研究表明,LDHs主層板的金屬元素種類和比例影響了復(fù)合氧化物晶型結(jié)構(gòu)、比表面積、還原能力和表面物種分布,并進一步探討鍛燒溫度對結(jié)構(gòu)的影響。在Co-Mn-Al催化劑體系中,當Co:Mn=1:2時,比表面積最大為128.04m2 g-1,孔徑分布更集中,晶粒最小,催化氧化苯轉(zhuǎn)化90%的溫度(T90)為238℃;在低溫條件下(350℃)鍛燒得到的氧化物結(jié)構(gòu)更完整、比表面積高,但在高溫條件下(550℃)得到的氧化物催化性能最好(T90=208℃),組分協(xié)同效應(yīng)增強。在Ce-Mn-Al氧化物催化劑體系中,Ce元素摻雜Mn-Al形成固溶體促進了 CeO2和MnOx的協(xié)同效應(yīng)、增大Mn4+/Mn3+和晶格氧(Olatt)比例,進一步促進催化氧化苯性能。(4)整體式薄膜催化劑催化氧化VOCs性能研究基于上述研究結(jié)果,采用原位生長技術(shù)在鋁箔上制備出一系列垂直生長的Co-Mn-Al LDHs,并以此為前驅(qū)體制備了整體式Co-Mn-Al氧化物薄膜催化劑,考察了對苯的催化氧化性能。研究結(jié)果表明,整體式Co-Mn-Al薄膜催化劑的最優(yōu)樣品催化氧化苯的T90為240℃,比二元的Mn-Al和Co-Al薄膜催化劑的T90分別降低了 25℃和60℃。整體式薄膜的結(jié)構(gòu)比粉體更復(fù)雜,單位質(zhì)量的反應(yīng)速率明顯優(yōu)于最優(yōu)的粉體催化劑,整體式薄膜的Oads/Olatt約為0.916,而粉體的Oads/Olatt約為0.55。金屬基整體式催化劑成功應(yīng)用于催化VOCs,為催化反應(yīng)器的制備奠定了一定實踐基礎(chǔ)。
[Abstract]:The situation in the country is more and more serious environmental pollution, to solve environmental problems imminent. Volatile organic compounds (Volatile organic, compounds, VOCs) as one of the air pollutants, not only damage the ecological environment, but also affect people's health. Catalytic oxidation technology is to solve the air pollution problem is one of the most effective ways to VOCs, and will not have two key pollutants. The problem is the development of low cost, high efficiency, good stability of catalyst. Hydrotalcite (Layered Double Hydroxides, LDHs) derived composite oxides obtained with porous, high surface area, synergistic effect, acid base bifunctionalized and highly dispersed grain characteristics, showed good application potential in the field of environmental catalysis, is the main function of system preparation of catalytic reactor components, especially monolithic thin film materials. The purpose of this paper is derived from multiple complex oxides were prepared by Co/Mn containing LDHs The catalyst on the surface morphology, structure and chemical properties, reveals the relationship between catalyst structure and catalytic oxidation performance; finally through the preparation of AB in situ growth perpendicular to the substrate surface integral film catalyst. The specific research contents and results are as follows: (1) the performance of the structure and regulation of catalytic oxidation of VOCs composite oxide by Co-Al a simple control of the reaction solvent (water, methanol and ethanol) and ammonia release agent (ammonia, six methyl four amine and urea) with different morphologies Co-Al LDHs were synthesized, including bending sheet, incomplete hexagonal tablets and compared their floccular, typical VOCs (benzene) oxide on the catalytic performance. The results show that the catalytic performance of CoAl oxide by ethanol and urea. The ball shape is better, the transformation rate of benzene at 230 DEG C for 99%. (2) structure defects and properties of oxide catalytic oxidation of VOCs in pure oxygen gas Under the condition, the Co2+ (3D7) Co3+ (3d6) oxidation of Co II Co III LDHs was successfully prepared, obtained after calcination. The oxide structure defects by laser Raman spectroscopy, H2-TPR, TPD and XPS characterization of oxide structure defects (acidic sites, oxygen defects and surface valence distribution), and compared with Co-Al oxide on benzene and toluene catalytic performance. The catalytic oxidation of benzene oxide prepared by in situ oxidation of toluene, complete the transformation temperature were 210 degrees and 220 degrees, with abundant structural defects, induced by good low-temperature reducibility, Lewis surface acidic sites and active oxygen (Oads). (3) composite component collaborative relationship effect and catalytic oxidation performance through the introduction of Co, three yuan LDHs the preparation of Ce doped Mn-Al LDHs were successfully calcined to form a series of layered composite oxides. The research results show that the LDHs main board metal elements influence the type and proportion of composite oxide crystal structure, The specific surface area, reducing power and surface species distribution, and to further explore the effect of calcination temperature on the structure. The Co-Mn-Al catalyst system, when Co:Mn=1:2, the maximum specific surface area is 128.04m2 g-1, the pore size distribution is more concentrated, the smallest grain size, the catalytic oxidation of benzene into 90% temperature (T90) at low temperature is 238 DEG C; under the condition of (350 C) get more complete calcined oxide structure, high specific surface area, but under the condition of high temperature (550 DEG C) oxide catalytic performance to get the best (T90=208 C), group synergy is enhanced. In the Ce-Mn-Al oxide catalyst system, Ce doped Mn-Al solid solution formed to promote synergy effect of CeO2 and MnOx, increased Mn4+/Mn3+ and lattice oxygen (Olatt) ratio, to further promote the performance of the catalytic oxidation of benzene. (4) the performance of VOCs thin film monolithic catalyst for catalytic oxidation based on the above research results, by in situ growth in aluminum foil The preparation of a series of vertical growth of Co-Mn-Al LDHs, and as a whole Co-Mn-Al oxide film prepared precursor, catalytic oxidation of benzene was studied. The results show that the optimal sample by catalytic oxidation of benzene with integral Co-Mn-Al thin film catalyst T90 240 C, two yuan more than the Mn-Al and Co-Al film catalyst the T90 were reduced by 25 degrees and 60 degrees. The monolithic structure of thin film is more complex than the powder, powder catalyst reaction rate was significantly better than the optimal unit quality, the whole film Oads/Olatt is about 0.916, while the Oads/ Olatt powder is about 0.55. metallic monolithic catalyst was successfully applied in the catalytic VOCs. As a catalytic reactor for the preparation of some practical basis.

【學(xué)位授予單位】：中國科學(xué)院大學(xué)(中國科學(xué)院過程工程研究所)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O643.36

【參考文獻】

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1 Gang Liu;Jiaqi Li;Kun Yang;Wenxiang Tang;Haidi Liu;Jun Yang;Renliang Yue;Yunfa Chen;;Effects of cerium incorporation on the catalytic oxidation of benzene over flame-made perovskite La_(1-x)Ce_xMnO_3 catalysts[J];Particuology;2015年02期

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本文編號：1590245