TiO2复合氧化物的制备及其在加氢脱硫中的应用

对TiO₂、TiO₂-Al₂O₃、TiO₂-SiO₂和TiO₂-ZrO₂载体的制备技术及其在加氢脱硫中的应用进行了综述。研究表明，以TiO₂调变的Al₂O₃、SiO₂和ZrO₂载体能影响MoO₃与Al₂O₃、MoO₃与SiO₂及MoO₃与ZrO₂之间的相互作用，改善MoO₃在载体表面的分散，促进其还原，有利于提高催化剂表面活性组分的数量，提高催化剂的加氢脱硫活性。     

MoP/TiO2-ZrO2催化剂制备及加氢脱氮性能考察

采用溶胶-凝胶法制备了TiO₂-ZrO₂复合载体,并用共浸渍法制备负载型MoP/TiO₂-ZrO₂催化剂,通过原位还原技术对催化剂进行还原处理后,在连续固定床反应器上进行活性评价。结果表明, TiO₂和ZrO₂物质的量比以及Mo负载量对催化剂活性有较大影响,当n(Ti)∶n(Zr)=4∶1和Mo负载质量分数为20%时,MoP/TiO₂-ZrO₂催化剂的加氢脱氮效果最好,并且TiO₂-ZrO₂复合载体比TiO₂-Al₂O₃复合载体的活性提高12.4个百分点。     

TiO2-SiO2复合氧化物载体及其加氢脱硫催化剂

分别采用溶胶-凝胶法和共沉淀法制备了TiO2-SiO2复合氧化物,并以此复合氧化物为载体制备了加氢脱硫催化剂.采用氮气恒温吸附脱附、X射线衍射、傅立叶变换红外光谱(FT-IR)和NH3程序升温脱附实验(NH3-TPD)对TiO2-SiO2复合氧化物及其催化剂进行表征,并考察催化剂的加氢脱硫性能.结果表明,TiO2经SiO2复合改性后,其热稳定性和晶相稳定性得到了提高.溶胶-凝胶法与共沉淀法相比,能使Ti物种和Si物种混合得更均匀,从而有利于制得具有较大比表面积和孔容的TiO2-SiO2复合氧化物.Ti含量增加,复合氧化物中Ti的分散度会降低.TiO2-SiO2复合氧化物中以Lewis酸中心为主,共沉淀法制备的复合氧化物比溶胶-凝胶法制备的复合氧化物具有更多的酸性中心.具有较大比表面积和较高酸性的催化剂对模型化合物噻吩和锦西重油催化裂化柴油的加氢脱硫性能较高.     

NiMo/ZrO2-Al2O3柴油深度加氢脱硫催化剂的研究

以ZrOCl₂·8H₂O和Al₂O₃为原料,采用包覆法制备了一系列不同ZrO₂含量的ZrO₂-Al₂O₃复合载体,并用等体积浸渍法负载活性金属,制备了相应的NiMo/ZrO₂-Al₂O₃加氢脱硫催化剂,以柴油为原料考察了催化剂的加氢脱硫活性,利用XRD、N₂吸附和UV-Vis DRS等技术对催化剂及载体的基本物性进行了表征。结果表明,在催化剂载体中引入适量的ZrO2,保持了Al₂O₃载体的孔道结构,降低了活性金属和载体的相互作用,有利于提高催化剂的柴油加氢脱硫活性,当载体中ZrO₂质量分数为10%时,催化剂表现出最高的催化活性,脱硫率达99.25%,产品中硫低于10 μg·g^－1,满足柴油欧-Ⅳ的硫含量标准。     

Co/TiO2-SiO2催化剂上肉桂醛选择性加氢制备肉桂醇

采用等体积浸渍法制备了系列Co/TiO₂-SiO₂催化剂,用于肉桂醛选择性加氢制备肉桂醇反应体系。系统考察了钴含量、焙烧温度、还原温度、稀土助剂等参数变化对钴催化剂选择性加氢性能的影响。结果表明,钴催化剂的活性和选择性与其表面钴的晶粒度有一定关系,较大尺寸的钴物种对肉桂醛加氢有利。当Co含量为15%、焙烧温度和还原温度均为823 K时,催化剂表现出良好的加氢性能。稀土助剂La和Ce的引入能改善Co /TiO₂-SiO₂催化剂表面活性组分钴的分散度,提高了钴催化剂的加氢性能。     

Co/TiO2-SiO2催化剂上肉桂醛选择性加氢制备肉桂醇

采用等体积浸渍法制备了系列Co/TiO₂-SiO₂催化剂,用于肉桂醛选择性加氢制备肉桂醇反应体系。系统考察了钴含量、焙烧温度、还原温度、稀土助剂等参数变化对钴催化剂选择性加氢性能的影响。结果表明,钴催化剂的活性和选择性与其表面钴的晶粒度有一定关系,较大尺寸的钴物种对肉桂醛加氢有利。当Co含量为15%、焙烧温度和还原温度均为823 K时,催化剂表现出良好的加氢性能。稀土助剂La和Ce的引入能改善Co /TiO₂-SiO₂催化剂表面活性组分钴的分散度,提高了钴催化剂的加氢性能。     

反应条件对Ni-Mo/TiO2-Al2O3催化剂上噻吩加氢脱硫的影响

采用溶胶-凝胶技术，从Al₂O₃载体的表面改性出发，制备了TiO₂-Al₂O₃复合载体，用此改性载体制备了NiMo/TiO₂-Al₂O₃催化剂；在中压固定床微反装置上考察了反应条件对噻吩加氢脱硫活性的影响。结果表明，在反应温度260～270 ℃、氢分压3.0 MPa、空速3.0～5.0 h^－1及氢油体积比480～550条件下，噻吩的转化率可达100％。     

负载型TiO2/SiO2光催化降解苯酚的研究

以白炭黑为载体、聚乙烯醇 (PVA) 和 Ti(SO₄)₂ 为原料， 在分散剂存在下直接焙烧制备超细负载型 TiO₂/SiO₂ 光催化剂， 结果表明， 在450 ℃焙烧2 h所制 SO₄^2-/TiO₂-SiO₂（SO₄^2-质量分数3.4%，TiO₂∶SiO₂=1∶6，比表面积54 m²/g）具有最佳光催化效果。光催化苯酚结果显示,在紫外灯下光降解苯酚（＜100 mg/L）符合零级动力学方程，催化活性随pH值的增加而增加，pH=10时表观速率常数[WTBX]k[WTBZ]=0.33 mg/L·min，为苯酚废水处理提供了一条简便易行、成本低廉的方法。同时考察了光催化剂制备因素对催化剂活性的影响。     

负载型TiO2 制备及其对茜素红的降解研究

以钛酸四丁酯和正硅酸乙酯为前驱体、冰醋酸为水解抑制剂，用溶胶-凝胶法制备纳米TiO₂/SiO₂复合物。通过X-射线衍射、红外光谱和比表面积仪等测试手段进行了分析，结果表明，纳米TiO₂ /SiO₂粒子焙烧后主要以锐钛型存在，有Ti—O—Si键的产生，复合粒子的比表面积达到389 m²·g^－1。光催化结果表明，n(Ti)∶n(Si)=3和焙烧温度为700 ℃的TiO₂/SiO₂粒子对茜素红溶液的降解性能最好。利用气质联用仪对降解产物进行了分析。     

ZrO2-Al2O3催化剂载体的制备及应用

ZrO₂-Al₂O₃复合载体具有独特的性能，当其作为催化剂载体时，可通过与活性组分的相互作用改变活性组分的分散状态及活性相结构，从而改善催化剂的催化性能。介绍了ZrO₂-Al₂O₃复合载体的制备以及组织结构、物相、表面酸性和与活性组分的相互作用等性能，并重点介绍了其在加氢脱硫反应中的应用。     

复合氧化物TiO2/SiO2性质研究

The nanometer particles of TiO2 and TiO2/SiO2 oxides were prepared by sol-gel and supercritical fluid drying method.The properties of TiO2 and TiO2/SiO2 were characterized by means of BET(Brunner-Emmett-Teller method), TEM(transmission electron microscopy), SEM(Scanning electron microscopy), XRD(X-ray differaction) and FTIR(Fourier transform-infrared) techniques.The effects of different preparation route,prehydrolysis and non-prehydrolysis,on the properties of TiO2/SiO2 oxide were also examined.Experimental results show that the termal stability of pure TiO2 is improved greatly when it is mixed with SiO2 in nanometer level.The composite TiO2/SiO2 oxides form Ti-O-Si chemical bonds,which creates new Broensted acidity stes.The acidity character is related to TiO2/SiO2 chemical composition and preparation methods.The acidity of TiO2/SiO2 oxides by prehydrolysis is greater than that of by non-prehydrolysis.Ti atom is rich on the surface of TiO2/SiO2.     

钛硅复合氧化物介孔材料在光催化降解罗丹明B中的应用

采用溶胶凝胶法以硫酸氧钛和水玻璃为前驱体制备二氧化钛-二氧化硅复合氧化物，利用XRD、SEM、TEM、BET、激光粒度仪、紫外-可见光谱等测试方法对二氧化钛-二氧化硅复合氧化物材料进行了测试分析，考察了制备条件对二氧化钛-二氧化硅复合氧化物材料的晶相、形貌、孔结构、粒度等物理性质的影响规律，并对其在紫外光区降解罗丹明B（RhB）溶液的性能进行了研究。结果表明：二氧化钛-二氧化硅复合氧化物具有优良的催化活性，其光催化活性明显优于市售的P25二氧化钛，焙烧温度对催化剂性能影响最大。     

Niobium sulfide as a dopant for Mo/TiO2 catalysts

Mo/TiO₂ catalysts were modified with Nb by two different methods, sol–gel and surface deposition, in order to study the effect of Nb incorporation on the thiophene HDS activity. The results show that the formation of Nb–Ti mixed oxides leads to catalysts with poor HDS activity while the deposition of Nb oxide species on the surface of TiO₂ leads to catalysts with activities larger than those of Mo/Al₂O₃ and Mo/TiO₂. This increase in activity was attributed to the formation of a larger population of Mo sulfur anionic vacancies when Nb was surface deposited on the TiO₂.     

复合氧化物TiO2/SiO2性质研究

The nanometer particles of TiO2 and TiO2/SiO2 oxides were prepared by sol-gel and supercritical fluid drying method. The properties of TiO2 and TiO2/SiO2 were characterized by means of BET(Brunner-EmmettTeller method), TEM(transmission electron microscopy), SEM(scanning electron microscopy), XRD(X-ray diffraction) and FTIR(Fourier transform-infrared) techniques. The effects of different preparation route, prehydrolysis and non-prehydrolysis, on the properties of TiO2/SiO2 oxide were also examined. Experimental results show that the thermal stability of pure TiO2 is improved greatly when it is mixed with SiO2 in nanometer level. The composite TiO2/SiO2 oxides form Ti-O-Si chemical bonds, which creates new BrSnsted acidity sites. The acidity character is related to TiO2/SiO2 chemical composition and preparation methods. The acidity of TiO2/SiO2 oxides by prehydrolysis is greater than that of by non-prehydrolysis. Ti atom is rich on the surface of TiO2/SiO2.     

TiO_2-ZrO_2-SiO_2复合载体催化剂制备及其负载磷化钼后的加氢脱芳性能

制备了不同配比的TiO_2-ZrO_2-SiO_2三元复合载体并对其负载磷化钼后的加氢脱芳性能进行了比较。XRD和BET表征结果表明,复合载体负载磷化钼后,晶型和表面结构、孔结构均发生较大变化;当Mo负载质量分数为20%时,晶相中有明显的MoO_3特征峰出现,但比表面积、孔径和孔容均有较大程度的降低。在反应温度320℃、压力3 MPa、体积空速2 h~(-1)和氢油体积比500:1的条件下,n(Ti)∶n(Zr)∶n(Si)=3∶1∶4的复合载体负载磷化钼后加氢脱芳效果最佳。     

还原条件对三元载体加氢催化剂加氢脱氮性能的影响

用原位溶胶凝胶法制备了不同TiO：含量的MoP／TiO2-SiO2-Al2O3催化剂,对含喹啉的模型化合物,在连续同定床反应器上进行。THDN活性评价（反应温度为300～400℃,反应压力为3．0MPa）。在不同还原条件下,对催化剂进行加氢脱氮活性评价。结果表明：还原条件对MoP／TiO2-SiO2-Al2O3催化剂加氢活性有较大影响,评价确定的最佳还原条件为：还原气速60mL／min,还原温度为600℃。     

非晶态TiO2-SiO2复合氧化物合成及其汽油氧化脱硫性能

采用沉淀法制备不同TiO₂含量的TiO₂-SiO₂复合氧化物,并用XRD、FT-IR、UV-VIS及TEM对样品进行表征,结果表明,TiO₂-SiO₂复合氧化物为非晶态结构。以过氧化氢-乙酸作为氧化体系,TiO₂-SiO₂复合氧化物为催化剂,考察TiO₂含量、反应温度、反应时间、过氧化氢用量和催化剂用量对汽油催化氧化脱硫效果的影响。结果表明,TiO₂质量分数为40%的TiO₂-SiO₂复合氧化物催化汽油氧化脱硫效果最好,在汽油用量10 g、冰醋酸用量0.5 mL、30%过氧化氢用量0.6 mL、催化剂用量为汽油质量的4%、反应时间60 min和反应温度40 ℃最佳条件下,汽油脱硫率为78%。     

Analysis of the hydrotreatment of Maya heavy crude with NiMo catalysts supported on TiO2-Al2O3 binary oxides: Effect of the incorporation method of Ti

Heavy Maya crude has been hydrotreated with NiMo/alumina-titania catalysts in which titania was incorporated by two different methods. Titania added to boehmite followed by calcination in order to promote formation of Ti–O–Al bonds, and Ti added to alumina in order to promote the formation of TiO₂ structures on the surface. The reaction results indicate that hydrodesulfurization (HDS), hydrodemetallization (HDM) and hydrodenitrogenation (HDN) activities are improved by the incorporation of Ti to the catalyst. In all cases, catalysts prepared by the method leading to the formation of surface TiO₂ structures show superior performance in the three functionalities (HDS, HDM and HDN). Raman analysis of the supports gives clear evidence of the differences in Ti oxide structures on the surface. The characterization of the catalysts indicates that Ti-modified catalysts have increased surface acidity (evaluated by pyridine adsorption) and greater number of coordinatively unsaturated sites (titrated by NO adsorption). Ti-containing catalysts seem to be also more stable with time-on-stream.     

Preliminary study on the TS-1 deactivation during styrene oxidation with H2O2

The deactivation of the TS-1 zeolite during styrene oxidation with H₂O₂ has been investigated by a series of kinetic experiments and further characterisation of the spent catalysts. A decline of the TS-1 activity with time has been observed, especially during the first hours of reaction. TG and TPD–MS analyses of the spent catalysts show that the main products occluded within the zeolite pores are styrene, phenylacetaldehyde and benzaldehyde. The presence of styrene oligomeric compounds has also been detected, although it is postulated they are formed mainly in the solution outside the zeolite pores. Diffusional hindrances due to the high degree of occupancy of the TS-1 pores, as well as, a strong adsorption of styrene, phenylacetaldehyde and benzaldehyde on the Ti sites are proposed as the main reasons for the TS-1 deactivation. These phenomena are enhanced at lower reaction temperatures, which cause a faster initial deactivation. Likewise, longer reaction times favour preferential chemisorption of aldehydes versus styrene.