V2O5-MoO3/TiO2 催化剂的NOx选择性催化还原及SO2氧化活性

采用浸渍法以TiO₂为载体制备V₂O₅-MoO₃/TiO₂ 选择性催化还原催化剂,研究V₂O₅和MoO₃负载量对于催化剂选择性催化还原反应及SO₂氧化活性的影响,并考察氧含量、氨氮物质的量比和反应空速对3%V₂O₅-6%MoO₃/TiO₂催化剂选择性催化还原脱硝活性的影响。结果表明,随着催化剂中V₂O₅负载质量分数增加,V₂O₅-MoO₃/TiO₂ 催化剂的选择性催化还原活性和SO₂氧化活性均呈上升趋势。MoO₃的负载对催化剂的SO₂氧化活性有明显抑制作用。MoO₃负载质量分数超过9%,制备的催化剂既保持较高的低温选择性催化还原活性,又使选择性催化还原反应中的SO₂转化率小于1%。     

不同载体对Pt-Sn催化剂丙烷催化脱氢性能影响

分别以Hβ分子筛和γ-Al₂O₃为载体,采用浸渍法制备不同Sn含量的负载型Pt-Sn双组分丙烷催化脱氢催化剂。在固定床微反装置上对制备的催化剂进行活性评价,并采用NH₃-TPD方法测定催化剂表面酸量和酸强度分布。结果表明,负载型Pt-Sn/Hβ和Pt-Sn/γ-Al₂O₃催化剂对丙烷催化脱氢反应性能与Sn含量密切相关,弱酸中心的存在对丙烷催化脱氢反应有利,对于特定的Pt-Sn体系,γ-Al₂O₃为载体的催化剂性能优于Hβ分子筛为载体的催化剂,当负载Sn质量分数为0.9时,Pt-Sn/γ-Al₂O₃催化剂性能最好。     

煤化工废水用改性分子筛催化剂的研制与表征

采用等体积浸渍法以ZSM-5分子筛为载体，制备负载分子筛催化剂。分别研究了不同活性物质、前驱体盐、焙烧温度和活性物质载量对催化剂性能的影响。通过BET检测、N₂吸附-脱附等温线、催化剂孔径分布、CWOO评价(包括催化剂抗硅性、间甲酚转化率和TOC去除率)方法对催化剂性能进行表征。研究表明：采用前驱盐Fe(NO₃)₃·9H₂O和活性组分Fe对载体ZSM-5分子筛进行负载，且活性组分负载量达到4%(质量分数)，并用500℃进行焙烧，制备出的负载分子筛催化剂具有较好的抗硅性、较高的间甲酚转化率与TOC去除率，综合性能最好。     

B2O3负载量对MoO3/CeO2-Al2O3耐硫甲烷化性能的影响

考察B₂O₃负载量对于MoO₃/CeO₂-Al₂O₃催化剂对耐硫甲烷化活性的影响,利用BET、XRD、TEM、NH₃-TPD等手段对催化剂进行了表征。结果表明,催化剂的耐硫甲烷化活性随B₂O₃负载量增加呈现先升高后降低的变化规律;当B₂O₃负载量为0.5%时,催化剂的耐硫甲烷化活性最高,CO转化率达到55%。结合表征分析,发现添加B₂O₃会影响催化剂载体的结构和表面酸度,从而影响活性组分的分散程度,进而影响MoO₃/CeO₂-Al₂O₃催化剂的耐硫甲烷化性能。催化剂的晶化程度太高或单位面积上的强酸量太多均不利于甲烷化反应;较好的活性组分分散度有利于催化剂甲烷化活性的提高。     

用于HC-SCR还原NOx的Cu基分子筛催化剂研究进展

烃类化合物选择性催化还原(HC-SCR)是一种有效的脱硝技术，但是在较低温度下Cu基分子筛催化剂用于HC-SCR催化还原NO_x存在催化活性较低、活性温度窗口较窄的问题。本文针对铜/分子筛催化剂选择催化还原NO_x的研究进展，系统介绍了负载型Cu基分子筛催化剂在HC-SCR应用中的反应机理以及载体、负载Cu含量、制备工艺、还原剂、H₂O和SO₂对催化活性的影响。发现掺杂与铜产生协同作用的金属助剂有助于提高低温催化活性。最后提出了制备具有优异低温催化活性的HC-SCR铜基分子筛催化剂的策略和今后开发高效性能催化剂的研究方向，例如适当增加Cu负载量、控制Si/Al比以及进一步提高金属活性组分的分散性。     

MoO2/g-C3N4催化剂的制备及其氧化脱除模拟油中的硫化物

采用高温煅烧MoO₂和g-C₃N₄混合物制备了不同MoO₂含量的MoO₂/g-C₃N₄催化剂。采用X射线粉末衍射（XRD）、傅里叶红外光谱（FTIR）、扫描电镜（SEM）和N₂吸附脱附对催化剂的结构和性能进行了表征。以MoO₂/g-C₃N₄作为催化剂,H₂O₂为氧化剂,离子液体为萃取剂研究了反应体系的氧化脱硫性能。这项研究中考察了不同煅烧温度下制得的催化剂、负载量、氧化剂使用量、催化剂加入量、反应温度、萃取剂使用量、反应时间、硫化物类型等不同反应参数对脱硫率的影响。结果表明,在H₂O₂的使用量为0.2mL,MoO₂/g-C₃N₄加入量为0.03g,1-乙基-3-甲基咪唑硫酸乙酯离子液体1.0mL,反应温度为70℃,反应时间60min的最佳工艺条件下,24%-MoO₂/g-C₃N₄催化剂脱硫率可以达到94.8%,催化剂循环使用5次后活性没有明显下降。此外,研究了MoO₂/g-C₃N₄在离子液体中的催化氧化反应机理。     

还原温度对Mo基催化剂物相及其加氢脱氧性能的影响

以碳纳米管(CNTs)为载体,通过控制催化剂合成的还原温度制备了一系列负载型Mo基催化剂。采用XRD、TEM、N₂物理吸附、XPS以及NH₃/H₂-TPD等技术对催化剂进行了表征,并研究了Mo基催化剂对硬脂酸催化加氢脱氧性能的影响。结果表明:随着还原温度的升高,催化剂表面的Mo物种逐渐被还原,还原过程为:MoO₃→MoO₂→Mo→Mo₂C。还原温度为450℃和550℃时,催化剂的活性相为MoO₂;还原温度为600℃时,催化剂的活性相为MoO₂/Mo/β-Mo₂C的混合相;还原温度为650℃和700℃时,催化剂的活性相全部转化为β-Mo₂C。与活性相MoO₂催化剂相比,β-Mo₂C催化剂具有更高的加氢脱氧活性。此外,还原温度为600℃的MoO₂/Mo/β-Mo₂C混合相催化剂因具有较大的比表面积、较多的酸中心数量和较强的H₂吸附能力,使得该催化剂在硬脂酸加氢脱氧反应中表现出最优越的催化活性。     

负载型杂多酸制备及对苯羟基化反应的活性研究

采用浸渍法和回流吸附法在γ-Al₂O₃、NaX型分子筛、TiO₂、SiO₂和椰壳活性炭载体上制备7种负载型杂多酸催化剂,并对催化苯羟基化制苯酚的反应活性进行研究。结果表明,制备的负载型杂多酸催化剂具有催化活性,且催化活性与负载方式和载体的种类有关,椰壳活性炭是硅钼钒杂多酸最好的载体,负载率达16.3%,苯酚收率7.4%,苯酚选择性97.1%。     

ZrO2添加对MoO3/Al2O3催化剂耐硫甲烷化性能的影响

采用共沉淀法制备了ZrO₂-Al₂O₃复合载体,并进一步制备了MoO₃/ZrO₂-Al₂O₃催化剂,考察了不同ZrO₂质量分数对催化剂结构及其耐硫甲烷化性能的影响。利用N₂物理吸附、X射线衍射、H₂程序升温还原和透射电子显微镜等手段对催化剂的结构进行了表征。结果表明,MoO₃/ZrO₂-Al₂O₃中ZrO₂的添加可以明显削弱MoO₃与载体间的相互作用,促进Mo物种的还原,适量ZrO₂的存在还有助于提高催化剂的比表面积,改善Mo活性相的分散性,使催化剂表现出优异的耐硫甲烷化活性。     

过渡金属改性Ce-M-Ox(M=Cu,Co, Mn和Fe)催化剂在NH3-SCR反应研究

采用共沉淀法制备了CeO₂上负载不同过渡金属元素Ce-M(M=Fe、Mn、Cu、Co)催化剂,研究了不同金属负载对CeO₂基催化剂脱硝活性影响。CeO₂催化剂中加入适量的过渡金属可降低催化剂结晶度,提高催化剂的氧化还原性和表面酸性,从而影响催化剂在NH₃-SCR中的催化性能。Ce-Fe、Ce-Mn催化剂中Fe³⁺和Mn³⁺的大量存在可提高催化剂的Lewis和Br?nsted酸性位点,提升催化剂对NH₃的吸附与活化性能,从而提升其催化性能。Ce-Mn催化剂具有优越的低温活性,Ce-Fe展现了较好的中高温活性,这与其催化剂的表面酸性密切相关。     

Selective catalytic reduction of NO with propene over CuMFI zeolites: dependence on Si/Al ratio and copper loading

Selective catalytic reduction of nitrogen oxide by propene in an oxidising atmosphere was studied on several CuMFI catalysts with different Si/Al ratios (11 Si/Al 100) and different copper loadings (between 0 and 5.5 wt.-%). From the results it was observed that the influence of zeolite Si/Al ratio on CuMFI catalytic activity for NO SCR by propene is dependent on the catalyst copper loading. Furthermore, the effect of catalyst copper loading on catalytic performance depended on the catalyst Si/Al ratio. The results also demonstrated that CuMFI catalysts with different Si/Al ratios and copper loadings, but with the same Cu/Al ratio and, therefore, the same copper exchange level have similar catalytic activity profiles for NO SCR.

It was further observed that not all Cu cations exchanged into MFI catalysts have equivalent catalytic activity for NO SCR, which made the existence of different copper environments on CuMFI catalysts evident, isolated Cu²⁺ ions being the most active species for NO SCR by propene.

Moreover, the results showed an improvement of the CuMFI catalytic activity at low temperatures by increasing the catalyst copper exchange level and, consequently, decreasing the number of Brönsted acid sites, which can be performed either by increasing the zeolite Si/Al ratio or copper loading.     

MoOx/SBA-15丙烷选择氧化催化剂的研究

采用浸渍法制备了一系列不同Mo含量的MoOx/SBA-15催化剂,并考察了丙烷选择氧化生成醛类含氧化合物（甲醛、乙醛和丙烯醛）的催化剂性能,利用FT-IR和XRD等技术对催化剂及载体的物化性能进行了表征。结果表明,催化剂的活性主要取决于Mo的负载量,当x(Mo)=1.75%［n(Mo)∶n(Si)=1.75∶100］时,醛类选择性约30%,总醛收率为10.4%,高分散催化剂尤其有利于醛类含氧化合物的定向生成。     

Ni/ZrO2催化剂的制备及甲烷分步水蒸气重整反应性能

采用沉淀法制备了ZrO₂载体,进一步采用浸渍法制备了不同Ni负载量的Ni/ZrO₂催化剂。通过XRD、N₂物理吸附、H₂-TPR和H₂-TPD等表征手段对Ni/ZrO₂催化剂的物理结构和化学特性进行了研究,探讨了活性金属Ni物种的状态,并计算了Ni粒子的大小。随着Ni负载量的增加,Ni/ZrO₂催化剂的比表面积逐渐减小,金属Ni的分散度逐渐减小,Ni粒子尺寸逐渐增大,低温H₂脱附峰所占比例逐渐增大。当Ni负载量为10.2%（质量分数）时,Ni/ZrO₂催化剂上ZrO₂晶粒的平均尺寸和Ni粒子的尺寸大小均接近30nm。进一步考察了Ni/ZrO₂催化剂在甲烷分步水蒸气重整反应中的催化性能。结果表明,Ni负载量在一定范围内的Ni/ZrO₂催化剂对于甲烷分步水蒸气重整反应具有良好的催化性能,Ni负载量过高或过低均不利于甲烷的转化。当Ni负载量为10.2%时,载体ZrO₂粒子和金属Ni粒子尺寸匹配,Ni/ZrO₂催化剂表现出最佳的甲烷转化活性和稳定性。     

Co/RPSA系列催化剂在N2O分解中的应用

采用正交试验设计方法设计和浸渍法制备分子筛RPSA负载Co、K、Ba和Sr催化剂,使用微型反应器评价催化剂用于直接分解N₂O的催化活性,考察活性组分对催化剂活性的影响。采用XRD、H₂-TPR和NH₃-TPD等方法对催化剂进行表征。结果表明,金属Co和K对催化剂活性影响显著,Co对提高催化剂活性有促进作用,Co含量增加,催化剂活性提高,而K对催化剂活性有抑制作用。催化剂表征结果显示,Co物种主要以Co₃O₄形式存在于载体表面,催化剂的组成和配比影响催化剂活性、氧化还原性能和酸性,催化剂强酸的存在有利于催化剂活性的提高。
     

复合氧化物催化剂催化氧化甲苯性能

以γ-Al2O3为催化剂载体,铜、锰为活性组分,稀土元素铈为助催化剂,采用浸渍法制备复合氧化物催化剂5%Cu/γ-Al2O3、5%Mn/γ-Al2O3、5%Cu-5%Mn/γ-Al2O3和5%Cu-5%Mn-1.6%Ce/γ-Al2O3,并考察其催化氧化甲苯性能。研究表明,复合氧化物催化剂催化氧化甲苯具有显著的效果,5%Cu-5%Mn/γ-Al2O3催化剂和5%Cu-5%Mn-1.6%Ce/γ-Al2O3催化剂表现出良好的低温活性和催化性能,对甲苯的完全燃烧温度分别为340℃和285℃。采用SEM和BET对催化剂进行表征,结果表明,催化剂的催化活性与活性组分在催化剂表面的分散度和催化剂的孔结构相关。     

NO decomposition and reduction by C3H6 over transition metal oxides supported on MgF2

The monooxides copper, manganese, molybdenum and chromium catalysts supported on MgF₂ were tested in NO decomposition and reduction by propene. The effect of the oxides content, time on stream and O₂ concentration in reaction mixture during NO reduction on their catalytic activity was investigated. All the catalysts showed the optimum active phase concentration corresponding to 2–4 wt.% of the metal. For the best copper catalyst an effect of introduction of another oxide (manganese or chromium oxide) on the catalytic performance was studied. The double copper-manganese oxide sample containing 2 wt.% Cu and 4 wt.% Mn was proved to ensure the best catalytic performance.     

Ti-modified alumina supports prepared by sol–gel method used for deep HDS catalysts

The typical physico-chemical properties and their hydrodesulfurization activities of NiMo/TiO₂-Al₂O₃ series catalysts with different TiO₂ loadings were studied. The catalysts were evaluated with a blend of two kinds of commercially available diesels in a micro-reactor unit. Many techniques including N₂-adsorption, UV–vis DRS, XRD, FT-Raman, TPR, pyridine FT-IR and DRIFT were used to characterize the surface and structural properties of TiO₂-Al₂O₃ binary oxide supports and the NiMo/TiO₂-Al₂O₃ catalysts. The samples prepared by sol–gel method possessed large specific surface areas, pore volumes and large average pore sizes that were suitable for the high dispersion of nickel and molybdenum active components. UV–vis DRS, XRD and FT-Raman results indicated that the presence of anatase TiO₂ species facilitated the formation of coordinatively unsaturated sites (CUS) or sulfur vacancies, and also promoted high dispersion of Mo active phase on the catalyst surfaces. DRIFT spectra of NO adsorbed on the pure MoS₂ and the catalysts with TiO₂ loadings of 15 and 30% showed that NiMo/TiO₂-Al₂O₃ catalysts possessed more CUS than that of pure MoS₂. HDS efficiencies and the above characterization results confirmed that the incorporation of TiO₂ into Al₂O₃ could adjust the interaction between support and active metals, enhanced the reducibility of molybdenum and thus resulted in the high activity of HDS reaction.     

铜含量对Cu/CeO2水煤气变换催化剂性能的影响

采用共沉淀法制备了不同铜含量的Cu/CeO₂水煤气变换催化剂，考察了铜含量对催化活性的影响。结果表明，Cu/CeO₂催化剂呈现出良好的水煤气变换活性。铜含量对催化活性有显著影响，铜摩尔分数为50%时，催化剂的低温活性最高，在200 ℃时CO转化率达到66.1%。Cu/CeO₂与FBD型铁基高温变换催化剂相比，具有低温活性好、活性温区宽的特点。用XRD、N2吸附法、H₂-TPR和CO-TPD对催化剂进行了表征，结果表明,无定形CuO、纳米颗粒CuO等可能是催化反应的活性物种，晶粒CuO对催化活性影响不大。铜含量的催化剂在不同温度下呈现出不同的活性。     

A comparative study of supported MoO3 catalysts prepared by the new “slurry” impregnation method and by the conventional method: their activity in transesterification of dimethyl oxalate and phenol

A new preparation method for supported MoO₃ catalyst, slurry impregnation, has been described and compared with the conventional impregnation method. Slurry MoO₃/water is used instead of the solution ammonium heptamolybdate, AHM [(NH₄)₆Mo₇O₂₄]. The MoO₃/γ-alumina, MoO₃/active carbon, and MoO₃/silica catalysts with different Mo loadings were prepared by slurry and by conventional method. The low solubility of MoO₃ was sufficient to transport molybdenum species from solid MoO₃ to the adsorbed phase. The equilibrium was achieved after several hours at 95 °C based on the loading amount of molybdenum. Only the process of drying was needed; calcination was not necessary and was left out. This is an important advantage for active carbon support because oxidative degradation of active carbon impregnated by molybdena starts at a relatively low temperature of about 250 °C during calcination on air. The activity was tested in the transesterification of dimethyl oxalate (DMO) and phenol at 180 °C. The dependences of catalytic activity on Mo loadings for the slurry prepared catalysts were similar to the dependences for the samples prepared by the conventional impregnation method with AHM. The activities of the slurry impregnation MoO₃/γ-Al₂O₃ catalysts were almost the same as those of catalysts prepared conventionally. Although the performances of slurry impregnation MoO₃/SiO₂ catalysts for transesterification of DMO were slightly better than those of the corresponding catalysts prepared by conventional impregnation, no waste solution and no calcining nitrogenous gases were produced. Therefore, we conclude that the new slurry impregnation method for preparation of supported molybdenum catalysts is an environmentally friendly process and a simple, clean alternative to the conventional preparation using solutions of (NH₄)₆Mo₇O₂₄. The present work will lead to a remarkable improvement in the catalyst preparation for the transesterification reaction.     

高硅铝比小晶粒NaY分子筛/高岭土复合物的合成及其催化裂化性能

以两种不同粒径的高岭土为原料,采用水热法合成了高硅铝比小晶粒NaY分子筛/高岭土复合物,通过XRD、SEM、晶粒度分析和N₂物理吸附等表征手段对复合物进行了结构和形貌表征。结果表明,与商品NaY相比,高岭土合成样品的结构稳定性和水热稳定性显著提高,以细化高岭土为原料合成样品的晶粒尺寸达310 nm,比表面积达807 m²·g^-1。以改性NaY分子筛/高岭土复合物为活性组分制备了催化裂化催化剂,采用NH₃程序升温脱附(NH₃-TPD)技术对其酸性特征进行了分析,并在小型微反装置上对其重油催化裂化性能进行了评价。研究结果发现,随着骨架硅铝比增大,催化剂表面酸中心强度增加,而酸量下降。采用细化高岭土合成的NaY分子筛/高岭土复合物的分子筛晶粒更小,催化剂酸中心数量以及催化裂化性能均大幅度提升。随着高温焙烧高岭土/偏高岭土质量比的增加,合成产物中的高岭土基质含量增加,催化剂表面酸中心强度下降。以原料高温焙烧高岭土/偏高岭土质量比为0.5,骨架硅铝比为6.1(摩尔比)的样品制备的催化剂,去柴重油转化率高达85.4%,同时有高达64.2%的汽油收率,表现出优异的重油催化裂化性能。