等离子体协同CuO/TiO2-γ-Al2O3催化CH4脱除NO

对合成的12%CuO/15%TiO2/γ-Al2O3催化剂进行了BET和XRD表征, 并结合等离子体与催化协同脱除NO的反应装置, 考察了单一等离子体、单一催化剂以及等离子体与催化协同脱除NO+CH4+O2的反应结果, 研究了上述三种条件下NO和CH4的转化率. BET表征结果表明, 15%TiO2/γ-Al2O3的孔径分布在微孔和介孔之间; XRD结果表明, 催化剂表面有CuO晶相; 反应活性数据表明, 单一等离子体存在时, NO和CH4的转化率随着等离子体的输入功率增大而逐渐增加, 反应体系引入体积分数为2.5%的O2气促进了NO和CH4的转化; 使用单一催化剂时, NO和CH4的转化率随温度升高而分别增大至30%和20%. 同时NO转化率随O2气浓度的增加先增加后降低, CH4随O2气浓度的增加转化率逐渐增大; 等离子体与催化剂协同作用NO+CH4+O2反应中, NO和CH4的转化率随O2气浓度的增加与只有催化剂存在条件下的变化趋势一致, 但是增大了NO的低温转化率, 同时CH4的转化率提高到了90%.     

镍钼杂多酸制备NiMo/γ-Al2O3催化剂及硼、钴或镍改性氧化铝的影响（英文）

A hydrotreating NiMo/γ-Al2O3 catalyst(12 wt% Mo and 1.1 wt% Ni) was prepared by impregnation of the support with the Anderson-type heteropolyoxomolybdate(NH4)4Ni(OH)6Mo6O18.Before impregnation of the support,it was modified with an aqueous solution of H3BO3,Co(NO3)2,or Ni(NO3)2.The catalysts were investigated using N2 adsorption,O2 chemisorption,X-ray diffraction,UV-Vis spectroscopy,Fourier transform infrared spectroscopy,temperature-programmed reduction,temperature-programmed desorption,and X-ray photoelectron spectroscopy.The addition of Co,Ni,or B influenced the Al2O3 phase composition and gave increased catalytic activity for 1-benzothiophene hydrodesulfurization(HDS).X-ray photoelectron spectroscopy confirmed that the prior loading of Ni,Co or B increased the degree of sulfidation of the NiMo/γ-Al2O3 catalysts.The highest HDS activity was observed with the NiMo/γ-Al2O3 catalyst with prior loaded Ni.     

Comparing the deactivation behaviour of Co/CNT and Co/γ-Al2O3 nano catalysts in Fischer-Tropsch synthesis

An extensive study of Fischer-Tropsch (FT) synthesis on cobalt nano particles supported on γ-alumina and carbon nanotubes (CNTs) catalysts is reported.20 wt% of cobalt is loaded on the supports by impregnation method.The deactivation of the two catalysts was studied at 220 C,2 MPa and 2.7 L/h feed flow rate using a fixed bed micro-reactor.The calcined fresh and used catalysts were characterized extensively and different sources of catalyst deactivation were identified.Formation of cobalt-support mixed oxides in the form of xCoO yAl2O3 and cobalt aluminates formation were the main sources of the Co/γ-Al2O3 catalyst deactivation.However sintering and cluster growth of cobalt nano particles are the main sources of the Co/CNTs catalyst deactivation.In the case of the Co/γ-Al2O3 catalyst,after 720 h on stream of continuous FT synthesis the average cobalt nano particles diameter increased from 15.9 to 18.4 nm,whereas,under the same reaction conditions the average cobalt nano particles diameter of the Co/CNTs increased from 11.2 to 17.8 nm.Although,the initial FT activity of the Co/CNTs was 26% higher than that of the Co/γ-Al2O3,the FT activity over the Co/CNTs after 720 h on stream decreased by 49% and that over the Co/γ-Al2O3 by 32%.For the Co/γ-Al2O3 catalyst 6.7% of total activity loss and for the Co/CNTs catalyst 11.6% of total activity loss cannot be recovered after regeneration of the catalyst at the same conditions of the first regeneration step.It is concluded that using CNTs as cobalt catalyst support is beneficial in carbon utilization as compared to γ-Al2O3 support,but the Co/CNTs catalyst is more susceptible for deactivation.     

不同助剂掺杂的铬基催化剂的制备及其对乙烷氧化脱氢的催化性能

以硝酸盐作为前驱体,Al₂O₃为载体,采用等体积浸渍法制备了系列不同助剂（Mn, Co, Ce）及不同助剂含量（1%, 3%, 5%, 7%, 10%）掺杂的铬基催化剂,其结构经X-射线粉末衍射(XRD)、 H₂程序升温还原(H₂-TPR)和CO₂程序升温脱附（CO₂-TPD）表征。并考察了催化剂对乙烷氧化脱氢反应的催化性能。结果表明：添加Co助剂有利于活性组分铬的分散,10Cr₃Co/γ-Al₂O₃催化剂表现出最佳催化性能,在反应温度为650 ℃, V(CO₂) ：V(C₂H₆)=3 ：1,空速(GHSV)为3 600 mL·（g·h）^-1条件下,在该催化剂上乙烯产率为36.5%。     

Ag/La0.6Sr0.4MnO3基催化剂上CH3OH和CO的完全氧化

合成了Ａｇ／Ｌａ０．６Ｓｒ０．４ＭｎＯ３、Ａｇ／Ｌａ０．６Ｓｒ０．４ＭｎＯ３／γ－ＡＩ２Ｏ３两毓催化剂,发现钙钛矿型Ｌａ０．６Ｓｒ０．４ＭｎＯ３对低浓度ＣＨ３ＯＨ或ＣＯ的完全氧化显示出相当高的催化活性,适量Ａｇ对钙钛矿型Ｌａ０．６Ｓ５０．４ＭｎＯ３基质的修使其对ＣＨ３ＯＨ或ＣＯ完全氧化催化活性获明显提高;在６％Ａｇ／２０％Ｌａ０．６Ｓｒ０．４ＭｎＯ３／γ－ＡＩ２Ｏ３催化剂 ,ＣＨ３ＯＨ完全氧化的Ｔ     

Ni-Co双金属催化剂上沼气重整制氢机理

用传统湿式浸渍法制备了La₂O₃掺杂的商业γ-Al₂O₃负载的沼气重整催化剂Ni-Co/La₂O₃-γ-Al₂O₃, 并用程序升温加氢(TPH)、程序升温氧化(TPO)、程序升温表面反应(TPSR)、程序升温脱附(TPD)及脉冲实验对催化剂进行了表征. 结果表明, 沼气重整过程中Ni-Co/La₂O₃-γ-Al₂O₃催化剂上的表面碳物种主要来源于CH₄的裂解, CO₂的贡献很小. CH₄裂解能够产生三种活性不同的碳物种, 即C_α、C_β与C_γ. 随着反应的进行, C_α物种减小而C_β与C_γ物种增加, 且C_γ物种能够转变为惰性的石墨碳. 重整反应过程中CH₄与CO₂的活化能相互促进. 催化剂表面的O物种与C反应生成CO或与CH_x反应生成CH_xO再分解为CO与吸附态的H物种, 可能是Ni-Co/La₂O₃-γ-Al₂O₃催化剂上沼气重整的速率控制步骤.     

β-Mo2N0.78/γ-Al2O3催化剂的制备及其噻吩加氢脱硫活性的研究

以γ-Al2O3为载体，钼酸铵为氧化钼前驱体，采用在N2-H2气氛下的程序升温还原氮化反应，制备β-Mo2N0.78/γ-Al2O3催化剂，以噻吩为模型化合物，考察了该催化剂的加氢脱硫反应性能，以及反应温度、氢还原预处理和钴、镍助剂的引入等因素对催化剂活性的影响。结果表明，在320 ℃～400 ℃之间，随着反应温度的升高，催化剂的活性逐渐增加；预还原则降低了催化剂的活性；添加钴、镍均在一定负载量范围内可以改善β-Mo2N0.78/γ-Al2O3催化剂的加氢脱硫活性，但镍对催化剂活性的影响要小于钴。     

La2O3对沼气重整制氢催化剂Ni/γ-Al2O3的影响

用浸渍法制备了不同La2O3含量的Ni/La2O3/γ-Al2O3催化剂, 用CH4/CO2体积比为1的混合气体模拟沼气, 考察了La2O3对沼气重整制氢催化剂Ni/γ-Al2O3的结构及催化性能的影响. 运用XRD、H2-TPR、BET及TEM等手段对催化剂进行了表征. 结果表明, La2O3对催化剂Ni/γ-Al2O3的影响主要取决于其含量. 载体中La2O3的添加增强了Ni与Al2O3之间的相互作用. 添加适量的La2O3能使催化剂具有更好的可还原性, 并能增加金属Ni的分散性, 抑制反应过程中Ni的烧结, 提高载体对CO2的吸附能力, 从而改善了催化剂的抗积炭性, 使催化剂具有较好的活性及稳定性. 反之, 过量La2O3的掺杂会使催化剂的抗积炭性及活性下降. 当La2O3含量为6%(w)时, 催化剂中Ni晶粒具有较好的分散性、还原性及抗积炭性, 从而使催化剂具有更好的活性及稳定性.     

氮、磷、碳化物比较研究初探

环保法规的日益严格使得研究者越来越重视新型加氢脱硫、脱氮催化剂的开发。国内外学者在对负载型Mo—Co、Mo—Ni和W—Ni等传统硫化物催化剂进行不断改进的同时，新型催化材料尤其是具有贵金属性质的过渡金属间充化合物一氮化物、碳化物和磷化物的研究也受到很大的关注。人们在探索不同的载体或者是不同的助剂对单金属间充化合物-氮化物、碳化物或磷化物催化剂活性组分的表面状态和结构以及其深度加氢脱硫脱氮性能的影响，而对同一载体负载的氮、磷、碳化物催化剂缺乏横向的比较。本研究制备了以γ-Al2O3为载体的负载型氮化钼、磷化钼和碳化钼催化剂，比较了它们的孔结构、比表面积，并初步分析了钼的质量分数为19％，氮化、磷化和碳化温度均为650℃时三类催化剂的二苯并噻吩加氢脱硫性能。     

Understanding the effect of cobalt particle size on Fischer-Tropsch synthesis: surface species and mechanistic studies by SSITKA and kinetic isotope effect

Co/γ-Al(2)O(3) catalysts with particle sizes in the range of 4-15 nm were investigated by isothermal hydrogenation (IH), temperature programmed hydrogenation (TPH), and steady-state isotopic transient kinetic analysis (SSITKA). Kinetic isotope effect experiments were used to probe possible mechanisms on Co/γ-Al(2)O(3) with different particle size. It was found that CO dissociated on Co/γ-Al(2)O(3) catalysts at 210 °C. The total amount of CO(2) formed following the dissociation depends on the cobalt crystal size. O-Co binding energy was found to be highly dependent on the Co metal particle size, whereas similar C-Co binding energy was found on catalysts with different Co particle size. Very strongly bonded carbon and oxygen surface species increased with decreasing particle size and acted as site blocking species in the methanation reaction. SSITKA experiments showed that the intrinsic activity (1/τ(CH(x))) remained constant as the particle size increased from 4 to 15 nm. The number of surface intermediates (N(CH(x))) increased with increasing particle size. The apparent activation energies were found similar for these catalysts, about 85 kJ/mol. D(2)-H(2) switches further confirmed that the particle size did not change the kinetically relevant steps in the reaction. The reactivity of the active sites on the 4 nm particles was the same as those on the 8, 11, and 15 nm particles, and only the number of total available surface active sites was less on the 4 nm particles than on the others.     

焙烧温度对CuO/γ-Al2O3和CeO2-CuO/γ-Al2O3催化剂NO还原活性的影响

用浸渍法制备了CuO/γ-Al2O3催化剂和CeO2改性的CeO2-CuO/γ-Al2O3催化剂,考察了焙烧温度对CuO/γ-Al2O3和CeO2-CuO/γ-Al2O3催化剂C3H6还原NO反应活性的影响,以及CeO2的添加量对CeO2-CuO/γ-Al2O3催化剂C3H6还原NO反应活性的影响。结果表明,在200 ℃～500 ℃的焙烧温度范围内,焙烧温度对CuO/γ-Al2O3催化剂的活性影响很小；在500 ℃～800 ℃的焙烧温度范围内,随着焙烧温度的升高CuO/γ-Al2O3催化剂的活性急剧下降,由XRD物相测定结果可知,归因于对反应表现惰性的尖晶石CuAl2O4相的生成。当焙烧温度为500 ℃时,CeO2的添加对CuO/γ-Al2O3催化剂的活性影响很小；当焙烧温度为800 ℃时,CeO2的添加对CuO/γ-Al2O3催化剂有明显的助催化作用,当Ce和Cu的摩尔比为1∶10时,NO转化率较为理想。     

Effect of cobalt precursors on the dispersion, reduction, and CO oxidation of CoO(x)/γ-Al2O3 catalysts calcined in N2

The present work tentatively investigated the effect of cobalt precursors (cobalt acetate and cobalt nitrate) on the physicochemical properties of CoO(x)/γ-Al(2)O(3) catalysts calcined in N(2). XRD, Raman, XPS, FTIR, and UV-vis DRS results suggested that CoO/γ-Al(2)O(3) was obtained from cobalt acetate precursors and CoO was dispersed on γ-Al(2)O(3) below its dispersion capacity of 1.50 mmol/(100 m(2) γ-Al(2)O(3)), whereas Co(3)O(4)/γ-Al(2)O(3) was obtained from cobalt nitrate precursors and Co(3)O(4) preferred to agglomerate above the dispersion capacity of 0.15 mmol/(100m(2) γ-Al(2)O(3)). Compared with Co(3)O(4)/γ-Al(2)O(3), CoO/γ-Al(2)O(3) catalysts were difficult to be reduced and easy to desorb oxygen species at low temperatures and presented high activities for CO oxidation as proved by H(2)-TPR, O(2)-TPD, and CO oxidation model reaction results. A surface incorporation model was proposed to explain the dispersion and reduction properties of CoO/γ-Al(2)O(3) catalysts.     

流化床甲烷部分氧化制合成气Ni催化剂及助剂La的作用

在流化床中,考察了不同Ni担载量的Ni/γ-Al2O3催化剂对POM反应的催化性能,以8％Ni最佳,TPR结果表明。催化剂表面主要有两种化学状态的NiO。当镍担载量≤2％时,催化剂表面 仅存在一种高温下才能被还原的NiO,在Ni催化剂中添加La,可削弱NiO与载体间的相互作用,并且可减缓在CH4＋O2气氛下升温过程中NiO与载体发生强相互作用 生成NiAl2O4,因此添加La的Ni催化剂在750℃就能引发甲烷部分氧化（POM）反应,且反应引发后可获得与经700℃H2还原后的Ni^0催化剂相同的反应性能。     

甲烷干重整催化剂Ni/Al2O3表面积炭表征与分析

用蒸发法制备了Ni/Al2O3催化剂及浸渍法制备了Ni/α-Al2O3和Ni/γ-Al2O3催化剂, 并与商品天然气水蒸气重整催化剂Z118Y一起进行了甲烷干重整实验, 考察了各催化剂上表面积炭行为. 通过H2程序升温还原(H2-TPR)、BET(Brunauer-Emmett-Teller)比表面积分析、X射线衍射(XRD)、透射电镜(TEM)、热重-差式扫描量热(TG-DSC)、程序升温氢化(TPH)等表征手段对催化剂表面沉积炭的特性进行了表征. 结果表明, 各催化剂上至少存在三种形式的碳物种: 无定形碳、丝状碳及石墨碳. 由于载体性质不同, 各催化剂上沉积炭的种类及其含量有所差别. Z118Y、Ni/Al2O3及Ni/α-Al2O3催化剂上主要沉积丝状炭, 而Ni/γ-Al2O3催化剂上则主要是石墨碳. Ni/γ-Al2O3催化剂中金属Ni颗粒较小(小于15 nm)、粒径分布范围较窄、分散性较好, 能减少催化剂表面炭的沉积, 有效地抑制丝状碳的生长.     

Study of Dibenzothiophene Adsorption Over Carbon Nanotube Supported CoMo HDS Catalysts

Adsorption properties of dibenzothiophene (DBT) on a CNT (carbon nanotube) support as well as on CoMoS/CNT and CoMoO/CNT catalysts have been studied. Consecutive desorption of adsorbates was measured by TGA. The commonly used carriers AC (activated carbon), γ-Al2O3, and their supported catalysts (CoMoO/AC, CoMoS/AC, CoMoO/γ-Al2O3, CoMoS/γ-Al2O3) were also subjected to analysis for comparison. The acidic properties of the samples were characterized using the NH3-TPD technique.Correlation between the adsorption of DBT and the acidic properties of the catalysts has been established.It was found that the Co-Mo catalysts in the sulfide state adsorbed much more DBT molecules than the corresponding Co-Mo catalysts in the oxide state. The CoMoS/CNT catalyst exhibited very high HDS activity and selectivity, as compared with the CoMoS/γ-Al2O3 catalysts. Based on the BET data and the high hydrogenolysis/hydrogenation selectivity of the CoMoS/CNT, it was deduced that more than 90% of the DBT molecules adsorbed on the CoMoS/CNT with an end-on mode, and the surface of the CoMoS/CNT catalyst was almost fully covered with DBT molecules. Although the AC support had very high surface area and high loading ability, the AC supported CoMoS catalyst showed lower HDS activity,as compared with the CoMoS/γ-Al2O3 catalyst.     

The remarkable enhancement of CO-pretreated CuO-Mn2O3/γ-Al2O3 supported catalyst for the reduction of NO with CO: the formation of surface synergetic oxygen vacancy

NO reduction by CO was investigated over CuO/γ-Al2O3, Mn2O3/γ-Al2O3, and CuOMn2O3/γ-Al2O3 model catalysts before and after CO pretreatment at 300 °C. The CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst exhibited higher catalytic activity than did the other catalysts. Based on X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/Vis diffuse reflectance spectroscopy (DRS), Raman, and H2-temperature-programmed reduction (TPR) results, as well as our previous studies, the possible interaction model between dispersed copper and manganese oxide species as well as γ-Al2O3 surface has been proposed. In this model, Cu and Mn ions occupied the octahedral vacant sites of γ-Al2O3, with the capping oxygen on top of the metal ions to keep the charge conservation. For the fresh CuO/γ-Al2O3 and Mn2O3/γ-Al2O3 catalysts, the -Cu-O-Cu- and -Mn-O-Mn- species were formed on the surface of γ-Al2O3, respectively; but for the fresh CuO-Mn2O3/γ-Al2O3 catalyst, -Cu-O-Mn- species existed on the surface of -Al2O3. After CO pretreatment, -Cu-□-Cu- and -Mn-□-Mn- (□ represents surface oxygen vacancy (SOV)) species would be formed in CO-pretreated CuO/γ-Al2O3 and CO-pretreated Mn2O3/γ-Al2O3 catalysts, respectively; whereas -Cu-□-Mn- species existed in CO-pretreated CuO-Mn2O3/γ-Al2O3. Herein, a new concept, surface synergetic oxygen vacancy (SSOV), which describes the oxygen vacancy formed between the individual Mn and Cu ions, is proposed for CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst. In addition, the role of SSOV has also been approached by NO temperature-programmed desorption (TPD) and in situ FTIR experiments. The FTIR results of competitive adsorption between NO and CO on all the CO-pretreated CuO/γ-Al2O3, Mn2O3/γ-Al2O3, and CuO-Mn2O3/γ-Al2O3 samples demonstrated that NO molecules mainly were adsorbed on Mn2+ and CO mainly on Cu+ sites. The current study suggests that the properties of the SSOVs in CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst were significantly different to SOVs formed in CO-pretreated CuO/γ-Al2O3 and Mn2O3/γ-Al2O3 catalysts, and the SSOVs played an important role in NO reduction by CO.     

低温等离子体协助B2O3/γ-Al2O3 选择催化还原NO（英文）

研究了低温等离子体协助催化条件下甲烷选择性催化还原NO反应(SCR).反应气体经等离子体活化后,生成NO2,HCHO,CH3NO和CH3NO2等活性更高的中间产物.程序升温表面反应表明,这些中间产物可在等离子体后置催化装置上进一步反应,从而使NOx还原为N2.在考察的一系列催化剂(包括γ-Al2O3,Ag/γ-Al2O3,B2O3/γ-Al2O3,Ga2O3/γ-Al2O3,In2O3/γ-Al2O3等)中,B2O3/γ-Al2O3表现出最好的催化活性.当反应温度为300oC时,NOx转化率达到最高.与γ-Al2O3催化剂相比,在10wt%B2O3/γ-Al2O3催化剂上,300oC时,NOx转化为N2的转化率从33.4%提高至51.0%.催化剂的酸性对于经等离子体活化后的反应气体在催化剂上的SCR反应起到重要作用.同时,催化剂上吸附态NOx对于NOx的转化也起到一定作用.     

乙烷在Pt/γ-Al2O3（001）模型催化剂上吸附行为的理论研究

本文采用密度泛函理论方法和周期性边界条件,考察了Pt原子与γ-Al2O3(001)表面上六种不同位点的相互作用,获得了最稳定吸附位的Pt/γ-Al2O3模型催化剂,建立了Pt原子负载在γ-Al2O3(001)表面的模型催化剂。同时,考查了乙烷分子在Pt/γ-Al2O3模型催化剂上的吸附行为。结果表明,在Pt/γ-Al2O3模型催化剂上,Pt原子转移了部分电子到载体γ-Al2O3。乙烷以分子态形式吸附在Pt/γ-Al2O3模型催化剂上,靠近Pt原子的C-H键受到一定程度地活化。     

Cr对Pt-Sn /γ-Al2O3催化剂丙烷脱氢性能的影响

通过H2-TPR、O2-脉冲等表征手段，结合丙烷脱氢催化性能考察了助剂Cr对Pt-Sn/γ-Al2O3催化剂反应性能的影响。结果表明，添加少量Cr可显著改善Pt-Sn/γ-Al2O3催化剂的脱氢稳定性，可提高丙烯选择性，降低催化剂表面积炭量。这是由Cr和Pt-Sn之间存在的协同作用引起的，一方面，Pt促进了Cr的还原，生成了可提高丙烯选择性的+3价Cr；另一方面，Cr使Sn变得难于还原，在强还原气氛下保持了活性氧化态价态，进而改善了催化剂的脱氢稳定性。     

Pretreatment of Alumina and Its Influence on the Properties of Co/Alumina Catalysts for Fischer-Tropsch Synthesis

16.6%Co/γ-Al_2O_3 catalysts prepared by incipient wetness impregnation method were used for Fischer-Tropsch synthesis.The support was pre-treated with different concentration of NH_4NO_3 aqueous solution.The effect of support pre-treatment on the properties of support and performance of supported- cobalt-based catalysts was investigated.To treat the support with NH_4NO_3 aqueous solution enlarged the pore ofγ-Al_2O_3,decreased the impurity Na_2O content,and weakened the surface acidity ofγ-Al_2O_3. The change in the properties of the support decreased the interaction between cobalt species and support, enhanced the CO hydrogenation rate and the C_(5 )selectivity.For all catalysts,increasing the reaction temperature increased the CO hydrogenation rate or the CO conversion,slightly decreased the total hydrocarbon selectivity,and favored the formation of methane and light hydrocarbons,while the chain growth probability decreased.For 16.6%Co/γ-Al_2O3 catalysts,prepared with the support treated with 100 g/L NH_4NO3 aqueous solution,the CO conversion,the CH_4 selectivity,and the C_(5 )selectivity were 83.13%,6.86% and 82.75% respectively,and the chain growth probability was 0.83 under the condition of 493 K,1.5 MPa,500 h~(-1)and the molar ratio of H_2 to CO being 2.0 in feed.