INVESTIGATION OF THE SURFACE CHARACTERISTICS AND CATALYTIC ACTIVITY OF Sb_xO_y/SiO_2CATALYSTS FOR VAPOR-PHASE SYNTHESIS OF ISOPRENE FROM ISOBUTYLENE AND FORMALDEHYDE

The surface characteristics and catalytic activity of Sb_xO_Y/ SiO_2 catalysts forvapor-phasc synthesis of isoprene from isobutylene and formaldehyde have been investi-gated by TPR, XRD, XPS, IR and catalytic activity evaluation. The results show that whenthe Sb loadings are less than about 5 wt%,Sb_xO_Y is compIctely dispersed on the surface ofsilica to form a surface compound with Sb(V)=O group and the catalysts have relativelyhigh catalytic activity; when the Sb loadings are more than 5 wt%, in addition to this surfacccompound, the crystalline α-Sb_2O_4 is formed on the support surface and causes rapid de-crease of catalytic activity. It is suggcsted that the catalytic activity of Sb_xO_Y /siO_2 catalystsresults from synetgistic catalysis of the surface compound Sb(V)=O as the basic sites andthe surface silanol Si-OH as the acidie sites. The mechanism of this synergistic catalysis forisoprene production is discussed.     

Studies on Kinetic Properties of Active Oxygen on the Surfaces of V_2O_5/SiO_2, V_2O_5-MoO_3/SiO_2 and V_2O5-P_2O5/SiO_2 Catalysts

Applying the TPD-MS with a high sensitivity of determination, the TPD spectrum of surface oxygen of V2O5/SiO2, V2O5-MoO3/SiO2 and V2O6-P2O5/SiO2 catalysts was obtained. The surface oxygen of these catalysts can be divided into three groups according to the desorption temperature. O2- desorbs mainly from 373K. to 423K, O- from 673K to 873K and O2- at above 873K. The activation energy and frequency factor of all the three kinds of oxygen species were calculated. Based on these results, the mechanism of oxygen desorption and the influence of P2O5 and MoO3 on the properties of oxygen supply of V2O5/SiO2 catalst were investigated. MoO3 and a small amount of P2Os increase the number of supplying oxygen and increase the activity of O- species. A large amount of P2O5 increases the number of supplying oxygen and restrains the activity of O- species.     

Syngas production by combined carbon dioxide reforming and partial oxidation of methane over Ni/α-Al_2O_3 catalysts

Ni/α-Al2O3 catalysts were found to be active in the temperature range 600 ～ 900℃ for both CO2 reforming and partial oxidation of methane.The effects of Ni loading,reaction temperature and feed gas ratio for the combination of CO2 reforming and partial oxidation of CH4 over Ni/α-Al2O3 were investigated.Catalysts of xwt%Ni/α-Al2O3(x=2.5,5,8 and 12) were prepared by wet impregnating the calcined support with a solution of nickel nitrate.XRD patterns and activity tests have verified that the 5wt%Ni/α-Al2O3 was the most active catalyst,as compared with the other prepared catalyst samples.An increase of the Ni loading to more than 5wt% led to a reduction in the Ni dispersion.In addition,by combining the endothermic carbon dioxide reforming reaction with the exothermic partial oxidation reaction,the loss of catalyst activity with time on stream was reduced with the amount of oxygen added to the feed.     

Effect of Ni loadings on the activity and coke formation of MgO-modified Ni/Al_2O_3 nanocatalyst in dry reforming of methane

MgO-modified Ni/Al2O3 catalysts with different Ni loadings were prepared and employed in dry reforming of methane （DRM）. The effect of Ni loadings on the activity and coke formation of Ni/MgO-A1203 catalysts were investigated. The synthesized catalysts were characterized by XRD, N2 adsorption-desorption, SEM, TPO and TPR techniques. The obtained results showed that increasing nickel loading decreased the BET surface area and increased the catalytic activity and amount of deposited carbon. In addition, the effect of gas hourly space velocity （GHSV） and feed ratio were studied.     

Complete Oxidation of Methane Alumina Modified with Calcium, over Palladium Supported on Lanthanum, and Cerium Ions

The activity and thermal stability of Pd/Al2O3 and Pd/（Al2O3＋MOx） （M=Ca, La, Ce） palladium catalysts in the reaction of complete oxidation of methane are presented in this study. The catalyst supports were prepared by sol-gel method and they were dried either conventionally or with supercritical carbon dioxide. Then they were impregnated with palladium nitrate solution. The catalysts with unmodified alumina had a high surface area. The activity and thermal stability of the aluminasupported catalyst was also very high. The introduction of calcium, lanthanum, or cerium oxide into alumina support caused a decrease of the surface area in the way dependent on the support precursor drying method. These modifiers decreased the activity of palladium catalysts, and they required higher temperatures for the complete oxidation of methane than unmodified Pd/Al2O3. The improvement of the palladium activity by lanthanum and cerium support modifier was observed only at low temperatures of the reaction.     

Influence of Pretreatment on the Interaction of Oxygen with Silver and the Catalytic Activity of Ag／SiO2 Catalysts for CO Selective Oxidation in H2

The interactions of oxygen with pre~reduced silver catalysts as well as their catalytic propertiesfor CO selective oxidation in H2 after oxygen pre-treatment are studied in this paper. It is found that the pretreatment exerts a strong influence on the activity and selectivity of the silver catalyst. A drop in activity and selectivity is observed after treating a pre-reduced catalyst with oxygen at low temperatures,whereas a converse result is obtained after an oxidizing treatment at high temperatures (T≥350℃). O2-TPD results show that surface oxygen species adsorbs on silver surface after the oxygen treatment at low temperatures. However, penetration of oxygen into the silver is enhanced by a high temperature treatment, meanwhile the surface oxygen species disappear. No other silver species except metallic silver are observed on all the catalysts by XRD, and the size of silver particle is not changed after the treatment with oxygen at low temperatures. The surface oxygen species formed by oxygen treatment can also be removed by hydrogen reduction. The strongly-adsorbed surface oxygen species prohibit the adsorption and diffusion of oxygen species in reaction gas on the surface of silver catalyst, causing the decrease in CO oxidation activity, in other words, it is important to obtain a clean silver surface for increasing the catalyst activity in CO removal from H2-rich feed gas. The differences in activity and selectivity due to the oxygen pretreatment at different temperatures axe discussed in terms of the changes in the surface/subsurface oxygen species of the silver particles.     

Investigation of Mechanisms About Effects of Promoters P_2O_5,K_2O and A1_2O_3 on Oxidation of o-Xylene to Phthalic Anhydride

We succeeded in designing an effective catalyst, V2O5-P2O5-K2O/Al2O3. SiO2, by which a high yield of PA,105wt% can be gained in middle-sized industrial fluidized bed apparatus without addition of any promoting gas.The mechanisms of effects of P2O5, K2O and Al2O3 on the surface properties of V2O5 were investigated by means of TPD and XRD. And the selectivity of oxidation are explained.Addition of a great deal of P2O5 restrains the activity of donating surface oxygen from V2O5, but increases the number of sites which donate surface oxygen. Addition of K2O promotes donation of surface oxygen from V2O6, and decreases the number of sites of donating oxygen, on the other hand, addition of K|O makes the surface structure of V2O5 catalysts more stable. Coating a small amount of Al2O2 onto support, SiO2, restrains the activity of donating oxygen and increases the number of sites of donating surface oxygen from V2O5.     

Simultaneous removal of ethanol, acetaldehyde and nitrogen oxides over V-Pd/γ-Al_2O_3-TiO_2 catalyst

V-Pd/γ-Al2O3-TiO2 catalysts with different vanadium contents were prepared by a combined sol-gel and impregnation method. X-ray diffraction (XRD), N2 adsorption-desorption (BET), X-ray photoelectron spectroscopy (XPS) and catalytic removal of ethanol, acetaldehyde and nitrogen oxides at low temperature (<300 ?C) were used to assess the properties of the catalysts. The results showed that the sample with 1wt% vanadium exhibited an excellent catalytic performance for simultaneous removal of ethanol, acetaldehyde and nitrogen oxides. The conversions of ethanol, acetaldehyde and nitrogen oxides at 250 ?C were 100%, 74.4% and 98.7%, respectively. V-Pd/γ-Al2O3-TiO2 catalyst with 1 wt% vanadium showed the largest surface area and higher dispersion of vanadium oxide on the catalyst surface, and possessed a larger mole fraction of V4+ species and unique PdO species on the surface, which can be attributed to the strong synergistic effect among palladium, vanadium and the carriers. The higher activity of V-Pd/γ-Al2O3-TiO2 catalyst is related to the V4+ and Pd2+ species on the surface, which might be favorable for the formation of active sites.     

Selective Oxidation of Toluene with Hydrogen Peroxide Catalyzed by V-Mo-based Catalyst

The selective catalytic oxidation of toluene with hydrogen peroxide over V-Mo-based catalysts under mild conditions was studied.The promotion effect of Mo on the catalysts was studied with V/Al2O3 and Mo/Al2O3 as reference samples.The catalysts were characterized by XRD,TPR,and XPS techniques.The results show that the addition of Mo to V/Al2O3 may change the distribution of V species on Al2O3 surface.Over V-Mo/Al2O3 catalyst,highly dispersed amorphous V species facilitates benzaldehyde formation,and crystalline V2O5 species increases the conversion of toluene but decreases the selectivity to benzaldehyde,while AlVMoO7 species favors both the conversion of toluene and the formation of cresols.The yield of benzaldehyde depends remarkably on the surface O/Al and Mo/V atomic ratios,and gets to a maximum value of 13.2% with a selectivity of 79.5% at an O/Al atomic ratio of 3.0 and Mo/V atomic ratio of 0.7.     

CO2 reforming of methane over nickel catalysts supported on nanocrystalline MgAl2O4 with high surface area

In this paper dry reforming of methane (DRM) was carried out over nanocrystalline MgAl2O4-supported Ni catalysts with various Ni loadings. Nanocrystalline MgAl2O4 spinel with high specific surface area was synthesized by a co-precipitation method with the addition of pluronic P123 triblock copolymer as surfactant, and employed as catalyst support. The prepared samples were characterized by X-ray diffraction (XRD), N2 adsorption, H2 chemisorption, temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), temperature- programmed desorption (TPD) and transmission and scanning electron microscopies (TEM, SEM) techniques. The obtained results showed that the catalyst support has a nanocrystalline structure (crystal size: about 5 nm) with a high specific surface area (175 m2 g-1) and a mesoporous structure. Increasing in nickel content decreased the specific surface area and nickel dispersion. The prepared catalysts showed high catalytic activity and stability during the reaction. SEM analysis revealed that whisker type carbon deposited over the spent catalysts and increasing in nickel loading increased the amount of deposited carbon. The nickel catalyst with 7 wt% of nickel showed the highest catalytic activity.     

NO-NH3-O2 reaction catalyzed by V2O5/AC at low temperatures

The effects of SO₂, V₂O₅ loading and reaction temperature on the activity of activated carbon supported vanadium oxide catalyst have been studied for the reduction of NO with NH₃ at low temperatures (150—250°C). It is found that SO₂ significantly promotes the catalyst activity. Both V₂O₅ loading and reaction temperature are vital to the promoting effect of SO₂. The catalysts with V₂O₅ loadings of 1—5 weight percent have a positive effect on the promotion of SO₂, while the catalysts with V₂O₅ loadings of above 7 weight percent have not such an effect or show a negative effect. At lower temperatures (<180°C) SO₂ poisons the catalyst but at higher temperatures promotes it. The reason of the SO₂ promotion was also discussed; it may results from the formation of SO₄ ^2? on the catalyst surface, which increases the surface acidity and hence the catalytic activity.     

同时脱除烟气中硫和硝的V2O5/AC催化剂研究

通过在固定床微反应器上对同时脱硫脱硝催化剂的研究,发现将V2O5担载在活性焦(AC)上制得的V2O5/AC催化剂可在200 ℃同时脱除烟气中的SO2和NO,其活性明显高于纯AC。V2O5/AC催化剂的脱硫脱硝活性与催化剂中钒的质量分数有关,随着V2O5质量分数从0.5%增至9%,硫容从3%增加到12%,脱硝率在V2O5质量分数为0.5%到3%时脱硝率稳定在60%左右,继续增加V2O5质量分数,脱硝率降低。程序升温脱附 (TPD) 和红外光谱 (FTIR) 表征结果显示在脱硫脱硝过程中,催化剂表面有H2SO4, 铵盐和VOSO4生成, VOSO4的质量分数随催化剂中V2O5质量分数的提高而升高。使用后的催化剂可通过5%NH3在300 ℃再生,再生后催化剂的脱硝活性明显增加,NO转化率从新鲜样的67%提高到接近100%,对SO2的吸附也比新鲜样有所增加。     

NO-NH3-O2 reaction catalyzed by V2O5/AC at low temperatures —Effects of SO2, V2O5 loading and reaction temperature

The effects of SO₂, V₂O₅ loading and reaction temperature on the activity of activated carbon supported vanadium oxide catalyst have been studied for the reduction of NO with NH₃ at low temperatures (150—250°C). It is found that SO₂ significantly promotes the catalyst activity. Both V₂O₅ loading and reaction temperature are vital to the promoting effect of SO₂. The catalysts with V₂O₅ loadings of 1—5 weight percent have a positive effect on the promotion of SO₂, while the catalysts with V₂O₅ loadings of above 7 weight percent have not such an effect or show a negative effect. At lower temperatures (<180°C) SO₂ poisons the catalyst but at higher temperatures promotes it. The reason of the SO₂ promotion was also discussed; it may results from the formation of SO₄ ²⁻ on the catalyst surface, which increases the surface acidity and hence the catalytic activity.     

V2O5-CeO2/TiO2催化剂上低温氨选择性催化还原NO的性能

考察了V2O5-CeO2/TiO2催化剂中V、Ce活性组分的担载量和焙烧温度对催化剂低温催化还原NO活性的影响及其在单独SO2、H2O和两者共存气氛下的抗毒化性能。结果表明,焙烧温度400℃下制备的5V30Ce/TiO2催化剂具有良好的低温催化还原NO活性,空速为10000h-1,165℃时NO转化率达99.2%;500℃以下低焙烧温度时,添加的Ce不与V相互作用,在催化剂表面主要以CeO2形式存在,有利于增大催化剂比表面积,增强V2O5在催化剂上的分散度,提高催化活性。而在500℃以上较高焙烧温度下,Ce与V会形成CeVO4,对活性提高不利。催化剂具有良好的低温抗水中毒性能,但受SO2毒化作用明显,其在SO2、H2O共存气氛下中毒程度较单独SO2下浅。     

V2O5-CeO2/TiO2-ZrO2催化剂表征及NH3还原NOx性能

商业选择性催化还原(SCR)催化剂V2O5-WO3(MoO3)/TiO2存在反应温度窗口窄(300–400 oC)和SO3转化率高等缺点,同时占催化剂总质量80%以上的载体TiO2比表面积小,热稳定性差.已有研究发现TiO2-ZrO2固溶体具有较大的比表面积和较强的表面酸性, TiO2与ZrO2的摩尔比为1：1时其比表面积达到最大. CeO2作为SCR催化剂的组成部分,由于其优良的储氧和放氧能力受到广泛关注.研究表明, CeO2-CuO, Ce/Ti-Si-Al和Mo2O3(Co2O3)/Ce-Zr等催化剂具有优良的SCR脱硝活性,同时对V2O5-WO3/TiO2催化剂进行CeO2改性,可提高催化剂的抗SO2中毒能力.实际烟气组分中同时存在SO2和H2O,必定会导致催化剂硫酸盐中毒,而目前对含Ce催化剂的硫酸盐中毒情况研究较少,因此开发新型高效脱硝催化剂十分必要.前期我们研究了xCeO2-3%V2O5/TiO2-ZrO2催化剂,发现CeO2可以显著拓宽脱硝温度窗口,同时增强催化剂酸性位点,但是V2O5含量较高时对环境及人体健康均有较大危害.本文采用共沉淀法制备摩尔比为1：1的TiO2-ZrO2固溶体,用浸渍法负载不同摩尔比的CeO2和1%的V2O5,得到一系列V-xCe/Ti-Zr催化剂,结合X射线衍射(XRD)、比表面积测试(BET)、高分辨透射电镜(HRTEM)、程序升温还原(H2-TPR)、原位漫反射红外光谱(in situ DRIFTS)和程序升温脱附(NH3-TPD)等手段分析催化剂的晶相、活性物质分散程度、氧化还原性质及表面酸性,在200–450 oC范围内考察Ce掺杂催化剂选择性催化还原NOx的脱硝活性,并在250 oC测试催化剂在NH3+NO+O2+SO2+H2O气氛中的脱硝活性,研究催化剂抗硫酸盐中毒能力.研究发现,CeO2掺杂可以拓宽脱硝反应活性窗口, V-0.2Ce/Ti-Zr (摩尔比Ce：Ti =0.2)表现出最优的脱硝性能,在250–350oC范围内脱硝效率均在92%以上,同时与前期研究结果对比发现CeO2含量较高时会导致高温段NOx转化率下降. XRD和HRTEM结果表明,ZrO2的添加可以显著降低载体TiO2的结晶度,复合氧化物TiO2-ZrO2呈无定形态, CeO2高度分散于载体之上,并且催化剂以单晶形式存在. H2-TPR结果表明,CeO2能显著提高催化剂的还原能力,主要的还原反应发生在CeO2的α(200–430oC)和β(430–600 oC)还原峰上,总体而言, V-0.2Ce/Ti-Zr表现出最大的氢气消耗量,即其还原性最强.低V2O5负载有利于较低温度SCR反应, V-0.3Ce/Ti-Zr的钒氧化物还原峰强度最大,其次是V-0.2Ce/Ti-Zr. NH3-TPD测试发现V2O5/TiO2主要存在中强酸及强酸,而V2O5/TiO2-ZrO2主要是弱酸, CeO2负载后随着其含量提高,弱酸强度增加.结合氨气原位漫反射红外光谱发现, CeO2可以增加催化剂Br?nsted和Lewis酸位数量,同时出现反应中间物–NH2, V2O5的负载量较高会抑制1660 cm–1处Br?nsted酸吸收峰的出现. BET结果发现, TiO2-ZrO2和V2O5/Ti-ZrO2比表面积分别可达255.73和143.77 m2/g, V2O5/TiO2仅为66.1 m2/g,表明ZrO2的添加可以显著增大催化剂比表面积,进而有利于SCR反应进行,沉积的氧化物进入载体孔道导致催化剂比表面积降低. V2O5-xCeO2/TiO2-ZrO2表现出较强的抗SO2中毒能力,但是在H2O存在条件下脱硝活性较差,可能是生成的硫酸铵盐及亚硫酸盐阻塞催化剂孔道所致. SO2和H2O停止通入后, V2O5-0.3CeO2/TiO2-ZrO2活性恢复至原有水平, V2O5-0.2CeO2/TiO2-ZrO2恢复至最初的84%.对中毒催化剂进行不同反应温度下的活性测试,发现V2O5-0.2CeO2/TiO2-ZrO2在中温段反应活性显著降低,可能是由于Ce(SO4)2的形成所致,由于V2O5-0.3CeO2/TiO2-ZrO2的Ce含量较高,其在此温度范围内活性依旧较高.两者在高温段NOx转化率均较高,推测是V2O5开始发挥活性组分作用的缘故.     

V2O5-Sb2O3-TiO2催化剂 低温NH3还原NO及其抗H2O和SO2毒化性能

浸渍法制备了催化剂V₂O₅-Sb₂O₃-TiO₂,考察了V₂O₅、Sb₂O₃负载量、pH值和焙烧温度对催化剂V₂O₅- Sb₂O₃-TiO₂低温氨选择性催化还原(SCR)NO活性的影响;同时,考察了催化剂V₂O₅-Sb₂O₃-TiO₂抗H₂O和SO₂毒化性能。结果表明,V₂O₅和Sb₂O₃负载量分别为5%和2%、焙烧温度为400℃、pH值为4时,催化剂SCR活性最好,反应温度220℃时,可达97%。Sb₂O₃的加入不仅能增强V₂O₅/TiO₂的催化活性,而且能明显提高催化剂的抗H₂O和SO₂毒化性能。SO₂、NO吸附暂态反应和TG-DTG测试表明,Sb₂O₃的促进机制主要是促进了催化剂在SO₂存在条件下对NO的吸附,同时,减弱了硫酸铵盐与催化剂之间的相互作用,硫酸铵盐更容易分解。     

V2O5/TiO2-ZrO2催化剂上甲醇选择氧化制甲缩醛

采用共沉淀法制备TiO2-ZrO2复合氧化物载体、等体积浸渍法制备V2O5/TiO2-ZrO2催化剂,对催化剂在温和条件下甲醇选择氧化生成甲缩醛(DMM)反应进行研究.结果表明,与单一氧化物载体TiO2或ZrO2负载的钒基催化剂相比,V2O5/TiO2-ZrO2对甲醇选择氧化具有较好的催化性能.XRD、NH3-TPD和...     

V2O5／TiO2催化剂的表面结构和酸碱性及氧化还原性

 研究了一系列锐钛矿担载的钒氧化物催化剂的表面性质．X射线衍射和Raman光谱表明，8％V2O5／TiO2催化剂上的V2O5处于单层分散状态．程序升温还原研究表明，单层分散的钒物种较易被还原，而形成多聚态和晶态后钒物种的还原温度升高．NH3吸附量热结果表明，在钒物种达到单层分散前，催化剂的表面酸性随钒担载量的增加而减弱，超过单层分散后，表面酸位的数目和强度基本不变．异丙醇脱氢／脱水反应结果表明，有O2时V2O5／TiO2催化剂显示出很强的氧化还原性，无O2时催化剂的脱水选择性较高．通过异丙醇的脱氢／脱水反应，将V2O5／TiO2催化剂的表面结构与其酸碱性和氧化还原性进行了初步的关联．     

氨再生条件对V2O5/AC同时脱硫脱硝活性的影响

对烟气同时脱硫脱硝过程中吸附SO2后的活性炭载V2O5（V2O5/AC）催化 吸附剂在含NH3气氛下的再生条件进行了考察，发现3%～5%NH3/Ar气氛、300℃、60min再生可有效恢复V2O5/AC的脱硫活性，并明显提高其脱硝活性。基于对SO2和NO的脱除率、再生后V2O5/AC的硫质量分数以及FT IR谱图分析发现，NH3的存在对V2O5/AC所吸附硫的脱附行为没有明显影响，但可显著改变V2O5/AC的表面化学性质，有利于烟气脱硫；NH3还可在V2O5/AC表面储存，显著促进脱硝。     

氨法选择性还原氮氧化物 V2O5/TiO2-PILC催化剂的抗硫性能

选择性催化还原(SCR)是目前去除氮氧化物最有效的方法之一. V2O5/TiO2催化剂被广泛应用于氨法选择性还原氮氧化物(NH3-SCR)反应,但该催化剂存在工作温度高(300–400oC)及 SO2氧化率高引起设备腐蚀和管路堵塞等问题,开发低温 SCR催化剂具有重要意义.过渡金属氧化物(如 Fe2O3, MnOx和 CuO等)催化剂用于低温SCR先后见诸文献报道,但这些催化剂在 SO2和 H2O存在下易失活.近年来柱撑黏土(PILC)引起科学家广泛关注, Yang等首次将 V2O5/TiO2-PILC催化剂应用于 NH3-SCR反应,发现其催化活性高于传统 V2O5/TiO2催化剂.柱撑黏土基催化剂在 NH3-SCR反应中也显示出良好抗硫性能,但 V2O5/TiO2-PILC催化剂的抗硫机理至今尚未见深入研究.因此我们制备了一系列 V2O5/TiO2-PILC催化剂,采用原位漫反射红外等方法详细研究了其抗硫性能较好的原因.
　　首先采用离子交换法制备出 TiO2-PILC载体,之后采用浸渍法制备了不同钒含量(质量分数x/%=0,3,4,5)的xV2O5/TiO2-PILC催化剂.同时,制备了传统 V2O5/TiO2和 V2O5-MoO3/TiO2催化剂作为对比.活性评价结果显示,4V/TiO2-PILC催化剂具有最高的催化活性,其催化性能与传统钒钛催化剂相当.在160oC时, NO转化率可达80%以上.同时,4V/TiO2-PILC催化剂还具有较宽的反应温度窗口,在260–500oC范围内, NO转化率保持在90%以上.向反应体系中加入0.05% SO2和10% H2O后,在低温(160oC以下)时所有催化剂的反应活性都有一定提高,可能是由于 SO2的加入提高了催化剂的表面酸性.继续升高温度,4V/TiO2和4V6Mo/TiO2催化剂活性均明显下降,而4V/TiO2-PILC催化剂的活性则未出现明显下降.原位漫反射红外光谱结果显示, SO2在三种催化剂表面的吸附以表面硫酸盐或亚硫酸盐物种以及离子态 SO42–物种形式存在,而在4V/TiO2-PILC催化剂表面离子态 SO42–物种的量最少. X射线光电子能谱及 O2程序升温脱附结果显示,在4V/TiO2-PILC催化剂上,表面吸附氧(Oads)的量最少.综合上述分析可以得出,在 SO2气氛下,离子态 SO42–物种在 SCR催化剂表面的累积可能是导致其失活的主要原因,而离子态 SO42–物种的形成可能与催化剂表面吸附氧的量有关.