共查询到20条相似文献,搜索用时 63 毫秒
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采用分步浸渍法制备了V-Mo-Sb/Ti催化剂,通过XRD、XRF、N2-吸附脱附、NH3-TPD、H2-TPR、UV-Vis、XPS等手段对催化剂的物化性能进行表征,通过固定床反应器考察了催化剂的脱硝性能及单质汞(Hg0)氧化性能.结果 表明,Sb的引入提高了V-Mo/Ti催化剂的比表面积、孔容、表面酸量、还原性能、... 相似文献
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分别制备了V-Mo/Ti和V-Mo-Nb/Ti脱硝催化剂,对比研究了两种催化剂的脱硝活性和抗Na中毒性能。采用XRD、BET、NH3-TPD、H2-TPR和XPS对催化剂进行表征分析。结果显示:添加Nb可有效抑制催化剂因Na中毒而导致的酸性、还原性下降,以及催化剂表面化学吸附氧的减少。因此,相比V-Mo/Ti-Na催化剂,V-Mo-Nb/Ti-Na催化剂体现了较好的脱硝活性。 相似文献
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低温选择性催化还原(SCR)脱硝催化剂是目前烟气脱硝领域研究的热点。利用超声浸渍法制备了FeOx-CeOx-MnOx-TiO2/石墨烯低温SCR脱硝催化剂,研究和分析了FeOx添加量对催化剂脱硝性能的影响,并借助TEM、XPS分析探究了FeOx在催化剂中的作用及内在机制。结果表明,当Fe/Mn摩尔比为0.2时,催化剂具有最佳的脱硝效果,在140 ℃即具有90%的NO转化率;同时对催化剂的抗SO2和抗水性能进行了测定,表明FeOx的添加有利于其抗性的提升,在SO2和水共存的情况下,仍具有80%以上的NO转化率。在此基础上,通过对比SCR反应前后催化剂的FT-IR分析结果,剖析了可能的抗SO2抗水机理 相似文献
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分别采用浸渍法和共沉淀法制备了In/Al_2O_3催化剂,并对其进行选择性还原氮氧化物的研究。结果表明:共沉淀法制备的催化剂具有较高的低温活性和NO选择性。以过渡金属Ti对载体进行改性,得到的In-Ti/Al_2O_3双金属组分催化剂具有高活性,这是由于表面存在无定型In氧化物且催化剂比表面积较高,同时TiO_2的加入减弱了In与Al_2O_3之间的相互作用,形成了无定型InTiO_2晶体,使In的还原温度移向低温。 相似文献
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采用钒钨钛催化剂可有效减排烧结烟气中NO和二噁英,而烟气中含有的钾盐会造成催化剂活性降低。在实验室采用湿式浸渍法对新鲜钒钨钛催化剂进行强制失活,研究了三种钾盐(K2SO4、K2O和KCl)负载于催化剂表面对其脱硝和脱二噁英活性的影响,并采用水洗和酸洗手段考察了失活催化剂的再生性能。结果表明,不同形态钾盐会造成催化剂的脱硝和脱二噁英活性降低,催化剂对两种污染物的活性降低顺序遵循相同的规律,即KCl> K2O> K2SO4。催化剂的失活机理主要包括物理失活和化学失活。物理失活主要是指钾盐在催化剂表面沉积并堵塞其孔道;化学失活主要是指钾盐与催化剂表面的活性组分产生相互作用,钝化表面活性位点,降低表面酸性,减弱氧化和还原性能,进而降低催化剂的脱硝和脱二噁英活性。再生实验结果表明,水洗可以一定程度上恢复催化剂的脱硝活性,酸洗会导致催化剂表面活性物质流失,但水洗和酸洗均无法有效恢复催化剂的脱二噁英活性。最后,提出了不同形态钾盐对钒钨钛催化剂的中毒机理。 相似文献
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利用超声浸渍法分别制备了MnOx/TiO2和CeOx-MnOx/TiO2低温选择性催化还原(SCR)脱硝催化剂,并对其进行了SEM、EDS、BET及XPS等表征,在此基础上,研究了催化剂的低温SCR脱硝性能,重点考察了Mn负载量及Ce/Mn摩尔比对催化剂性能的影响,结果表明:当Mn负载量为15%时,催化剂具有较高的催化活性;Ce的掺杂有利于催化剂催化活性的提升,当Ce/Mn=0.8时,其催化活性最高,在180℃时达到了97.86%。另外,Ce的掺杂有利于提升催化剂的抗硫抗水特性,但仍有待进一步提升。 相似文献
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采用浸渍法制备锰改性硫酸活化稀土尾矿催化剂,探究硫酸浓度和锰改性量对催化剂脱硝活性的影响,并通过BET、XRD、H2-TPR和NH3-TPD等表征手段对催化剂性能进行分析。结果表明,硫酸浓度为3 mol/L时催化剂的反应温度窗口为350~450℃,在400℃时达到最佳脱硝效率67%;继续添加5%Mn改性后,催化剂的反应温度窗口向低温移动至250~350℃,在此温度范围内N2选择性保持在70%以上,并在300℃时达到最佳脱硝效率86%。随着硫酸浓度的增加,催化剂的比表面积先增大后减小,孔容、孔径迅速减小。硫酸活化增加了催化剂表面酸性位点的数量,提高了催化剂对NH3的吸脱附能力。锰元素在催化剂表面以无定形态存在。锰改性催化剂在低温段较强的氧化还原能力是其反应温度窗口较硫酸活化催化剂低的主要原因。 相似文献
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从废脱硝催化剂中回收有价金属钨的研究 总被引:1,自引:0,他引:1
用碳酸钠浸出结合季铵盐萃取工艺从失效脱硝催化剂中回收钨。结果表明,在浸出条件为碳酸钠浓度100 g/L、液固比2∶1、浸出温度180℃、浸出时间3 h时,钨的浸出率可达98.5%。浸出液经过三辛基甲基氯化铵萃取、碳酸氢铵溶液进行反萃,可在水相中得到高浓度的钨酸铵溶液,并与溶解在有机相之中的Fe、K等杂质元素进行高效分离。 相似文献
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Sm and Ho were doped in Ce-Mn/TiO2 catalyst respectively to enhance its denitration performance at low temperature.X-ray diffraction(XRD),N2 adsorption-desorption,X-ray photoelectron spectroscopy(XPS),NH3-temperature programmed desorption(NH3-TPD),H2-temperature programmed reduction(H2-TPR) and in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS) techniques were used to analyze the structure and performance ... 相似文献
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Zhenghua Hu Dongqi An Lei Zhang Xuping Wang Siyong Fang Xinyun Tian Liu Qiu Jingfang Sun Tingzhen Li Lin Dong 《中国稀土学报(英文版)》2024,(3):515-522
The sulfated CeO2/Al2O3 catalysts with different sizes of CeO2 nanoparticles were prepared by using pure H2O or acetic acid solution as impregnation solvent, and the influence of sizes of CeO2 nanoparticles on the catalytic performances of the sulfated CeO2/Al2O3 catalyst was studied. The catalytic performance tests show that the sulfated CeO2/Al2O3 catalyst using a... 相似文献
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Nanogranular Ti (3 nm)/Ni(30 nm)/Ti(t nm) (t=1, 3, 5, 7, 10) films were prepared by facing magnetron sputtering from Ti and Ni onto glass substrates at room temperature. The structural and magnetic properties of films strongly depended on the Ti layer thickness. X-ray diffraction (XRD) patterns of all as-deposited films showed strong FCC Ni(111) peak. Vibrating sample magnetometer (VSM) measurements indicated that the perpendicular coercivity of the Ti (3 nm)/Ni (30 nm)/Ti (3 nm) film reached about 36 kA/m. With the increase of Co layer thickness, coercivity (Hc) first increased and then decreased. The grain size and magnetic clusters slightly increased and the value of roughness (Ra) was smallest at t=3 nm. 相似文献
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粉末冶金钛花管的研制 总被引:2,自引:0,他引:2
介绍了以边皮海绵残钛为原料,采利氢化-脱氢粉末冶金方法及热扩散表面处理技术,制取强度高、抗腐蚀、耐磨损钛花管的工艺过程及粉末冶金钛花管的使用效果。 相似文献
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Nanogranular Ti(3 nm)/Ni(30 nm)/Ti(t nm )(t=1,3,5,7,10) films were prepared by facing magnetron sputtering from Ti and Ni onto glass substrates at room temperature.The structural and magnetic properties of films strongly depended on the Ti layer thickness.X-ray diffraction(XRD) patterns of all as-deposited films showed strong FCC Ni(111) peak.Vibrating sample magnetometer(VSM) measurements indicated that the perpendicular coercivity of the Ti(3 nm)/Ni(30 nm)/Ti(3 nm) film reached about 36 kA/m.With the increase of Co layer thickness,coercivity(Hc) first increased and then decreased.The grain size and magnetic clusters slightly increased and the value of roughness(Ra) was smallest at t=3 nm. 相似文献
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Perovskite oxides LaCoO_3 prepared by templating, co-precipitation and sol-gel method with different complexants were systematically characterized and its catalytic performances for CO oxidation were investigated. The samples were characterized by X-ray diffraction, thermogravimetry analysis and differential scanning calorimetry, N_2 physisorption, transmission electron microscopy, temperature program reduction of hydrogen, temperature program desorption of oxygen and X-ray photoelectron spectroscopy measurement, results of which show that the properties of LaCoO_3, such as surface morphology, surface area, surface compositions, redox capability, oxygen vacancy, as well as the calcination temperature and formation mechanism, depend intimately on the preparation method. Catalytic tests indicate that the sample prepared by carbon templating method shows the best activity for CO oxidation, with full CO conversion obtained at 135 ℃. In particular, the catalyst can be activated and significant increase of activity can be obtained with the increase of reaction time. The cyclic and longterm stability of catalysts were discussed and compared. 相似文献
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《中国稀土学报(英文版)》2020,38(7):725-734
The effect of manganese and/or ceria loading of V_2 O_5-Mo_O_3/TiO_2 catalysts was investigated for selective catalytic reduction(SCR) of NO_x by NH_3.The manganese and/or ceria loaded V_2 O_5-MoO_3/TiO_2 catalysts we re prepared by the wetness impregnation method.The physicochemical characteristics of the catalysts were thoroughly characterized.The catalytic performance of 1.5 wt% V_2 O_5-3 wt% MoO_3/TiO_2(V1.5 Mo3/Ti) is greatly enhanced by addition of 2.5 wt% MnO_x and 3.0 wt% CeO_2(V1.5 Mo3 Mn2.5 Ce3/Ti) below450℃.Compared with the V1.5 Mo3/Ti catalyst with NO_x conversion of 75% at 275 ℃,V1.5 Mo3 Mn2.5 Ce3/Ti exhibits higher NO_x conversion of 84% with good resistance to SO_2 and H_2 O at a gas hourly space velocity value of 150000 h~(-1).The active manganese,cerium,molybdenum,and vanadium oxide species are highly dispersed on the catalyst surface and some synergistic effects exist among these species.Addition of MnO_x significantly enhances the redox ability of the cerium,vanadium,and molybdenum species.Addition of Ce increases the acidity of the catalyst.More active oxygen species,including surface chemisorbed oxygen,form with addition of Mn and/or Ce.Because of the synergistic effects,appropriate proportions of manganese in different valence states exist in the catalysts.In summary,the good redox ability and the strong acidity contribute to the high NH3-SCR activity and N2 selectivity of the V1.5 Mo3 Mn2.5 Ce3/Ti catalyst in a wide temperature range.And the V1.5 Mo3 Mn2.5 Ce3/Ti catalyst shows good resistance to H_2 O and SO2 in long-time catalytic testing,which can be ascribed to the highly sulfated species adsorbed on the catalyst. 相似文献
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Al2O3 and Ce-Zr mixed oxides are important components of the automobile three-way catalyst.Various contents modifying A12O3(GAL) was physically introduced into Ce-Zr-Al mixed oxides(CZA) to form series of GAL/CZA composition.The Pd/Rh catalyst samples were prepared by different GAL/CZA support loading Pd/Rh,then aged at 950 oC for 6 h.The catalytic behavior of different Pd/Rh catalyst samples was studied.Surface area,oxygen storage capacity(OSC) and H2 adsorption capacity(TPR) of fresh and aged samples were... 相似文献
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借助电子背散射衍射(EBSD)技术,以罩退生产的冷轧Ti-IF钢及含磷Ti-IF高强钢为目标,分析不同磷、钛合金质量分数对产品特征织构的影响。结果表明,磷元素虽然有利于γ取向线上{111}〈112〉织构的增加,但也增加了组分强度差,不利于塑性应变比r值,并且磷元素对{111}织构发展的促进作用取决于钢中过剰钛的质量分数,过剩钛质量分数过高会促进FeTiP二相粒子的析出,从而阻碍{111}取向再结晶晶粒的长大,弱化{111}面织构的强度。研究结果对该材料合金成分的调整起到了指导作用。为了保证所生产的含磷IF高强钢获得一定的强度,同时兼备良好的冲压性能,应降低IF钢中的钛质量分数,适当加入铌以弥补因钛减少对间隙原子固定产生的影响。 相似文献