钙钛矿型催化剂La_（0.8）M_（0.2）CoO_3（M=Sr、Ce、Ba、Ca）催化燃烧VOCs的活性与抗硫性研究

用柠檬酸溶胶-凝胶法制备了La0.8M0.2CoO3（M=Sr、Ce、Ba、Ca）4种钙钛矿型复合氧化物催化剂.甲苯催化燃烧活性测试表明,4种催化剂均具有很好的催化活性,转化率达到90%时反应温度都在340℃以下,比LaCoO3下降20℃—70℃,催化性能依次为：La0.8Sr0.2CoO3〉La0.8Ce0.2CoO...     

催化燃烧用稀土催化剂CM系列的研究及应用 Ⅰ.燃烧催化剂性能研究

研究了含铜、锰、过渡金属、稀土混合氧化物燃烧催化剂。着重研究稀土的加入方法、浸渍次数对催化活性的影响。结果表明,稀土以分散在各次浸渍液中浸渍,以二次浸渍为宜;在第二载体中加入Y_2O_3能降低催化剂的起燃温度和提高催化剂的耐热性。     

助剂Fe添加对柱状MnO_x/PG-AC催化剂低温选择性催化还原(SCR)性能影响

采用等体积浸渍法制备Mn Ox/PG-AC、Mn Ox-Fe Oy/PG-AC催化剂,并通过X射线衍射(XRD)、X射线光电能谱(XPS)及场发射扫描(FESEM)等表征手段分析了Fe的掺杂对催化剂低温脱硝活性的影响.分析表明,助剂Fe的加入促进活性组分锰氧化物具有更好的分散性,为催化剂提供了更多的催化活性位点,同时助剂Fe的掺杂明显调控了活性组分Mn4+/Mn3+的价态比.一定量Fe的掺杂显著提高了催化剂的低温选择性催化还原(SCR)性能.当Fe/Mn的物质的量之比为0.8时,Mn Ox-Fe Oy/PG-AC/300℃催化剂表现出最佳的低温SCR脱硝活性     

掺杂方法对Cu-OMS-2催化氧化甲苯性能的影响

分别采用前掺杂法(PI)、离子交换法(IE)和浸渍法(IM)合成了过渡金属Cu掺杂的催化剂Cu-OMS-2,通过XRD、BET、XPS、H_2-TPR等手段对催化剂的结构进行表征,并测试催化剂对甲苯的催化燃烧性能.XRD结果显示,全部掺Cu样品与单纯OMS-2晶相峰相同;XPS结果表明,Cu掺杂有效调控了Mn~(3+)/Mn~(4+)的比例,催化剂表面形成不同数量氧空位,其中前掺杂法和离子交换法制备的催化剂表面生成了更多的氧空位;H_2-TPR结果显示Cu掺杂降低了催化剂还原温度,且前掺杂法和离子交换法制备的催化剂的还原温度低于浸渍法合成的样品.因此,前掺杂法和离子交换法合成的催化剂在甲苯催化氧化中显示出较高的催化活性.     

氟里昂12(CCl2F2)燃烧分解催化剂性能的研究

本文对贵金属、氧化物和复合氧化物体系催化剂上氟里昂_(12)(F_(12))燃烧分解反应进行了活性评价和稳定性研究.结果表明:TiO_2,ZrO_2/TiO_2催化剂对氟里昂_(12)燃烧分解反应具有良好的低温催化活性和较好的稳定性,ZrO_2/TiO_2催化剂具有一定的臭氧-催化氧化活性     

基于CeO_2/TiO_2催化H_2O_2氧化低温脱硝的实验研究

以H_2O_2为氧化剂对NO进行低温氧化脱硝,考察了非催化和纳米TiO_2催化作用下的H_2O_2氧化低温脱硝性能;并以纳米TiO_2为载体,采用等体积浸渍法掺杂过渡金属氧化物CeO_2进行改性,制备了一系列CeO_2/TiO_2催化剂,探究了其催化作用下H_2O_2的氧化脱硝性能,并筛选获得了催化剂的最佳CeO_2负载量;进一步针对最优催化剂,考察了不同烟气工况对催化剂活性的影响,并进行了XRD、H2-TPR以及XPS等表征分析.表征结果显示,CeO_2的负载量会影响催化剂中晶格氧的含量,晶格氧相对含量的增加有利于氧化还原反应中的电子传递,这是促进H_2O_2活化分解的关键.实验结果表明,CeO_2/TiO_2催化剂能有效促进H_2O_2的活化分解实现低温脱硝,且CeO_2负载量为3%wt时,催化活性最高;在烟温为160℃、[H_2O_2]/[NO]物质的量比为2以及空速为30000 h-1时,NO转化率最高可达76%.     

铁源对Fe/ZSM-5催化剂氨选择性催化还原NO的影响

采用浸渍法,在相同的铁含量条件下,以硝酸铁、氯化亚铁、硫酸亚铁为前驱体制备了3种不同铁源Fe/ZSM-5分子筛催化剂.研究了铁源对Fe/ZSM-5催化剂NH_3-SCR活性的影响,并采用X射线衍射(XRD)、比表面积和孔结构(BET)、X射线光电子能谱(XPS)、氢气程序升温还原(H_2-TPR)及氨程序升温脱附(NH_3-TPD)等表征手段对催化剂的结构和理化性质进行测定.结果表明,不同的铁源对Fe/ZSM-5催化剂低温段(低于350℃)的NH_3-SCR催化性能影响较大,其低温活性顺序为:Fe(Cl)/ZSM-5 Fe(S)/ZSM-5 Fe(N)/ZSM-5.以氯化亚铁为铁源的Fe(Cl)/ZSM-5催化剂取得最佳的NH_3-SCR催化活性,在233℃时NO转化率达到90%.表征结果表明,样品Fe(Cl)/ZSM-5中形成了最多的孤立Fe~(3+)物种及中酸位数量.孤立Fe~(3+)物种有利于增强Fe/ZSM-5催化剂的低温还原性能,改性过程中形成的中等强度酸性位有利于提高催化剂低温NH_3-SCR催化性能.     

Cr/γ-Al_2O_3对乙酸乙酯的催化燃烧

使用浸渍法制备不同负载量的Cr/γ-Al_2O_3催化剂,研究乙酸乙酯的催化燃烧.BET,XRD结果表明,Cr在γ-Al_2O_3上负载存在分散阈值效应,负载量在阈值以下时呈单层分散形式,在超过阈值时Cr形成结晶,实验测得单层分散阈值与理论计算一致.Raman结果表明Cr在单层分散时为Cr~(6+),而在非单层分散时为Cr_2O_3.催化乙酸乙酯燃烧的活性研究显示,阈值效应对催化活性有显著影响:催化活性在单层分散阈值时最好,此时活化能最高,指前因子最大.     

LaMnO3纳米空心球的制备及其催化性能研究

采用碳微球模板法制备了LaMnO3纳米空心球催化剂,采用热重分析、X射线衍射、扫描电子显微镜、透射电子显微镜和比表面积分析仪(BET)对催化剂进行了表征,利用程序升温反应评价了催化剂用于消除汽车尾气中CO和碳氢化合物的催化活性.通过系统的研究发现,采用煅烧温度600℃制备的LaMnO3纳米空心球具有最高的催化活性.     

整体式Mn基复合金属氧化物催化燃烧VOCs性能研究

以堇青石为载体,采用浸渍法制备Mn-M/Cordierite(cord)(M=Co、Ce、La、Cu、Ni)复合金属氧化物催化剂,考察其催化燃烧甲苯的性能,并通过SEM、XRD和H_2-TPR对催化剂进行表征,结果表明,MnO_x和CoO_x之间具有相互作用,MnCo催化剂具有最高的甲苯催化活性,T_(50)和T_(90)分别为243℃和259℃.改变Mn和Co的比例,发现当Mn∶Co=2∶3时,Mn_2Co_3催化剂具有最高的甲苯和乙酸乙酯的催化性能,T_(90)分别为252℃和238℃.     

氧化铈在非贵金属燃烧催化剂中热稳定性的研究

本文考察了Ｃｅ含量对提高催化剂的热稳定性的作用，并采用Ｘ－射线衍射分析Ｃｅ含量对催化剂活性组成的影响。结果表明，合适的Ｃｅ含量能够提高催化剂的热稳定性，这主要是氧化铈能够阻止ＮｉＣｏ２Ｏ４相的生成，而ＮｉＣｏ２Ｏ４的生成对本系列催化剂的燃烧活性是不利的。实验还表明，在空气气氛下有利于形成ＮｉＣｏ２Ｏ４相，在Ｎ２／Ｈ２Ｏ气氛中不利于ＮｉＣｏ２Ｏ４相的生成。     

Removal of toluene from air streams by cobalt-copper bimetallic catalysts supported on sepiolite

Abstract

Oxidative removal of toluene using copper and cobalt bimetallic catalysts with varying molar ratios supported on sepiolite was investigated. The catalysts prepared by a deposition precipitation method and were characterized using X-ray diffraction, nitrogen adsorption-desorption, field emission scanning electron microscopy, H₂-temperature-programmed reduction, transmission electron microscope, and inductive coupled plasma atomic emission spectroscopy. The species supported on sepiolite are Co₃O₄, CuO, and CuCo₂O₄. The activities of the tested catalysts increased in the order 0Co-4Cu/Sep <1Co-3Cu/Sep <4Co-0Cu/Sep <1Co-1Cu/Sep <3Co-1Cu/Sep. The latter exhibiting 90% toluene oxidative degradation at 288?°C within 15?h, having high selectivity towards CO₂, and being stable at 300?°C up to 15?h. In conclusion, this study showed that sepiolite has excellent properties as a support.     

Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst for selective catalytic reduction of NOx

• Activated carbon was proposed to be an efficient accelerant for molded red mud catalyst. • The surface acidity and reducibility were highly improved, as well as the pore structure. • The enrichment of the surface Fe²⁺ and the adsorbed oxygen account for the improvement. Our previous study proved that the acid-pretreatment process could efficiently activate red mud (RM) for the selective catalytic reduction (SCR) of NO_x. However, in terms of the molding process, which is the key step determining whether it can be applied in large-scale industrial, the surface acidity and reducibility of catalyst always decreased dramatically, and part of surface area and pore structure were lost. In this study, we prepared monolithic honeycomb red mud (MHRM) catalysts with activated carbon (AC) as an accelerant and investigated the effect of AC on the MHRM. The results showed that the MHRM with 3 wt.% of AC (MHRM-AC3) exhibited the best SCR performance, and kept more than 80% NO_x conversion in the range of 325°C–400°C. Compared with the MHRM, MHRM-AC1, and HMRM-AC5, the MHRM-AC3 has more mesoporous and macroporous structures, which can provide more adsorption active sites. The AC significantly improved NH₃ adsorption and surface reducibility, which was mainly due to the increase of the surface acid sites (especially the Brönsted acid sites), the concentration of Fe(II), and the surface adsorbed oxygen. The presence of more Fe(II) enriched the surface oxygen vacancies, as well as the surface adsorbed oxygen, due to the charge imbalance and unsaturated chemical bond. And surface adsorbed oxygen exhibited more active than lattice oxygen owing to its higher mobility, which was conducive to NO_x reduction in the SCR reaction.     

聚乙烯及其废料油化技术中催化剂的研制与性能研究

本文研究了几种自制催化剂对聚乙烯热解产物的催化改质作用,催化反应温度与催化剂性质对催化改质所得气体收率及组成、汽油收率及辛烷值、柴油收率以及催化剂积碳的影响,探讨了适合聚乙烯及其废料热解产物催化改质的催化剂应具备的特性及热解产物在催化剂上反应的类型,同时探讨了本研究对废塑料油化技术的指导作用。应用此催化剂液体收率可达８０％以上,汽油辛烷值为８２（ＲＯＮ）。     

过渡金属对Pt Rh Pd/Al2O3催化剂性能的影响

研究了过渡金属(重点考察了铜)对Pt Rh Pd／Al2O3催化剂尾气净化效能的影响,并应用XRD,TPD,TPR等手段对过渡金属在Pt Rh Pd／Al2O3催化剂中的作用机制进行了探讨．结果表明,过渡金属对Pt Rh Pd／Al2O3催化剂具有较大的改性作用,过渡金属与混合贵金属产生的协同效应有利于催化剂活性的提高．     

Pd掺杂对Fe,Co系钙钛矿型三效催化剂性能的影响

用共沉淀法制备了LaFeO3，LaFe0.96Pd0.04O3，LaCoO3，LaCo0.96Pd0.04O3四种催化剂，用X－射线衍射仪（XRD）对催化剂进行了结构分析。程序升温还原（TPR）实验揭示催化剂中存在两种类型的氧种：α氧和β氧。活性评价和TPR实验表明，α氧是CO和C3H6氧化反应的活性氧种，而C3H8的氧化则由α氧和β氧共同来完成。Pd的掺杂可使ABO3中β氧的活性增强，从而使三效活性得以明显提高。     

CuO-ZnO催化剂的XRD和EXAFS研究

用XRD和EXAFS方法研究了CuO-ZnO(50:50)CO_2加氢合成甲醇催化剂的结构.XRD研究发现,在催化剂还原前后,分别存在CuO,ZnO和Cu-ZnO晶相.EXAFS研究发现,在CuO-ZnO中,Cu—O,Cu—Cu键长及Cu的氧配位数、Cu的Cu配位数与纯CuO的十分接近,在Cu-ZnO中,Cu—Wu键长、Cu的Cu配位数与纯Cu的十分接近,说明催化剂在还原前后,CU的近邻结构分别与CuO与Cu的十分接近.纯Cu的活性、选择性很低,而Cu-ZnO的活性、选择性较纯Cu的有很大提高,说明催化剂的性能与催化剂中Cu的近邻结构无关.     

水中直接染料的多相催化脱色的试验条件研究

实验结果表明，金属氧化物催化剂与活性炭和过氧化氢配合使用，对直接染料有很高的催化脱色率。反应进行迅速，以直接耐酸大红4BS和直接红棕RN为代表的正交实验表明影响催化脱色作用的主要因素为催化剂，其次是活性炭和过氧化氢。直接深蓝L－3RB，直接铜蓝2R，直接黑L－3BQ，直接耐晒黄RS，直接青莲RB等的最大脱色率为92.9%-99.5%。     

Promotional effect of ion-exchanged K on the low-temperature hydrothermal stability of Cu/SAPO-34 and its synergic application with Fe/Beta catalysts

• K⁺ hinder the structural degradation of Cu/SAPO-34 under humid condition<100°C. • K⁺ on Cu/SAPO-34 brings lower acidity and inferior SCR activity at high temperature. • Fe/Beta was used to compensate the low activity of Cu/SAPO-34 at high temperature. • The hybrid catalysts with KCu/SAPO-34 and Fe/Beta show a great potential for using. K ions were introduced onto Cu/SAPO-34 catalysts via the ion-exchange process in order to improve their stability under low-temperature hydrothermal aging. The changes in structure and copper-species contents of these catalysts upon hydrothermal aging were probed in order to investigate their effects on selective catalytic reduction (SCR) activity. For the fresh Cu/SAPO-34 catalysts, K ions had little influence on the chabazite framework but effected their acidities by exchanging with acid sites. After hydrothermal aging, the structural integrity and amount of active sites decreased on pure Cu/SAPO-34. While the K-loaded catalysts showed improved chabazite structure, acidity, and active site conservation with increasing K loading. However, although the 0.7 wt% K catalyst maintained the same crystallinity, active site abundance, and low-temperature SCR activity as the fresh catalyst upon aging, an apparent decrease in SCR activity at high temperature was observed because of the inevitable decrease in the number of Brönsted acid sites. To compensate for the activity disadvantage of K-loaded Cu/SAPO-34 at high temperature, Fe/Beta catalysts were co-employed with K-loaded Cu/SAPO-34, and a wide active temperature window of SCR activity was obtained. Thus, our study reveals that a combined system comprising Fe/Beta and K-loaded Cu/SAPO-34 catalysts shows promise for the elimination of NO_x in real-world applications.     

苯胺的超临界水氧化研究1

苯胺的超临界水氧化表明,氧化剂Ｈ２Ｏ２、试验温度、压力和停留时间以及水样的起始ＴＯＣ值对ＴＯＣ的去除率有显著影响．在本试验中,选取了硫酸铜、硫酸铁、硫酸锰等金属盐进行苯胺的均相催化氧化试验研究,结果表明,这些金属盐对苯胺的氧化有不同的催化活性,筛选出硫酸锰和和硫酸亚铁进行了进一步的研究．以硫酸锰作催化剂为例,在４５０℃,２８ＭＰａ,Ｋ＝１．１,ｐＨ＝４．０的条件下,当停留时间为４６ｓ时,ＴＯＣ去除率达到１００%．