TiO_2-SiO_2复合氧化物载体的pH值和焙烧温度对催化剂的辛烷异构化性能的影响

采用溶胶-凝胶法制备TiO_2-SiO_2复合氧化物载体,通过超声浸渍法制备Ni O和WO3改性负载的Ni O-WO3/TiO_2-SiO_2催化剂,考察不同p H值和焙烧温度条件下制备的载体对催化剂辛烷异构化性能的影响。结果表明,制备的Ni O-WO3/TiO_2-SiO_2催化剂呈多孔结构,平均孔径约5 nm,平均晶粒尺寸(10~20)nm。以焙烧温度500℃和p H=2条件下制备的TiO_2-SiO_2为载体,制得的催化剂比表面积达322.51 m2·g-1,在辛烷异构化反应中,正辛烷转化率为28.3%,选择性85.1%。     

溶胶—凝胶工艺涂膜对玻璃纤维性能影响的研究

利用溶胶—凝胶(Sol—gel)涂膜工艺,在无碱玻璃纤维表面涂SiO_2、SiO_2—TiO_2和SiO_2—TiO_2—ZrO_2系统的氧化物膜.探讨了不同的涂膜工艺参数对纤维强度的影响,研究发现涂膜后纤维的强度和耐碱性均提高.本文利用IR、XPS、SEM测试方法对涂膜纤维表面的形貌和结构进行了研究.     

高稳定性金红石型TiO_(2)-SiO_(2)载体的制备及表征

采用均匀沉淀法制备金红石TiO_(2)纳米颗粒,再通过溶胶-凝胶法制备一系列不同TiO_(2)含量的金红石型TiO_(2)-SiO_(2)纳米复合物载体,利用比表面积及孔径分析仪、XRD、SEM、FT-IR、UV-vis DRS等对载体结构进行表征,考察TiO_(2)-SiO_(2)载体的高温稳定性。结果表明,TiO_(2)-SiO_(2)载体具有较大的比表面积和典型的SiO_(2)凝胶孔结构,其中的TiO_(2)晶型和晶粒尺寸与纯TiO_(2)相同。高温焙烧后,与纯TiO_(2)发生严重烧结相比,TiO_(2)-SiO_(2)载体表现出优异的高温稳定性,复合材料中的SiO_(2)发生轻微烧结,比表面积和孔容基本不变,其中的TiO_(2)仍保持高分散性,晶粒尺寸不变。TiO_(2)-SiO_(2)载体中未生成Ti-O-Si化学键,而且复合结构对金红石TiO_(2)的能带结构影响较小,TiO_(2)和SiO_(2)只是纳米尺度上的混合,所以SiO_(2)的空间结构是提高TiO_(2)颗粒高温稳定性的主要原因。     

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.     

负载型NiMo加氢处理催化剂氧化物载体研究进展

以NiMo在加氢精制中的应用为线索,按催化剂载体的不同,简介了以单一氧化物和复合氧化物为载体的催化剂的制备方法,总结了NiMo为活性组分,氧化物为载体的加氢精制催化剂的应用进展。按照载体的不同,从单一氧化物载体Al_2O_3,TiO_2和SiO_2,以及复合氧化物载体角度总结了催化剂在加氢精制中的应用。氧化物载体具有热稳定性好,酸碱性适宜的特点,一直是人们研究的重要内容。     

负载型NiMo加氢处理催化剂氧化物载体研究进展

以NiMo在加氢精制中的应用为线索,按催化剂载体的不同,简介了以单一氧化物和复合氧化物为载体的催化剂的制备方法,总结了NiMo为活性组分,氧化物为载体的加氢精制催化剂的应用进展。按照载体的不同,从单一氧化物载体Al_2O_3,TiO_2和SiO_2,以及复合氧化物载体角度总结了催化剂在加氢精制中的应用。氧化物载体具有热稳定性好,酸碱性适宜的特点,一直是人们研究的重要内容。     

纳米Ni-Mo复合氧化物催化剂加氢脱氧性能研究

用溶胶-凝胶法制备了非负载Ni-Mo复合氧化物催化剂,用X-射线能谱、N_2吸附-脱附、SEM等手段对催化剂进行了表征。以苯酚和乙酸为探针分子考察了在制备过程中添加硝酸铝和乙醇对催化加氢脱氧性能的影响。由结果可知:溶胶-凝胶法可制备纳米结构的Ni-Mo复合氧化物催化剂,颗粒尺寸达70 nm;溶胶凝胶溶液中不添加硝酸铝可提高催化剂中活性组分Mo和Ni的利用率;溶剂中乙醇的体积分数为50%所制备的催化剂具有较高加氢脱氧活性,在0.3 MPa,270℃,液时空速2 h~(-1)的条件下,催化剂催化苯酚加氢脱氧的脱氧率达到98.4%。     

Ni/ZrO_2-SiO_2催化剂催化乙酰丙酸加氢合成γ-戊内酯

分别以ZrO_2、SiO_2及ZrO_2-SiO_2复合氧化物为载体,采用等体积浸渍法制备了Ni含量为10%(质量分数)的催化剂,考察了其催化乙酰丙酸液相加氢性能。采用N2-物理吸附、NH3-TPD、H2-TPR、XRD、TEM等表征手段对催化剂进行了表征。研究结果表明,在所制备的催化剂上,乙酰丙酸先经C=O加氢生成4-羟基戊酸,后者快速脱水酯化为γ-戊内酯。Ni/ZrO_2-SiO_2催化剂较Ni/ZrO_2与Ni/SiO_2催化剂具有高的金属分散度和丰富的表面酸性中心,表现出高的C=O加氢活性以及优异的乙酰丙酸加氢合成γ-戊内酯性能。在反应温度为200℃,氢气压力4 MPa的反应条件下,乙酰丙酸的转化率达到100%,γ-戊内酯的选择性大于99.9%。     

掺入SiO_2对TiO_2热催化剂的影响

以ZrO_2为载体,掺入SiO_2的TiO_2作为活性成分,制备负载型催化剂,考察掺入SiO_2对TiO_2热催化剂的影响。结果表明,掺入SiO_2后生成Ti—O—Si,使TiO_2和ZrO_2载体结合的更为牢固。SiO_2能有效抑制TiO_2从锐钛矿转变成金红石,同时抑制锐钛矿型的生成。掺入SiO_2物质的量分数达到15%时,900℃焙烧仍能得到100%的锐钛矿。TiO_2-SiO_2在ZrO_2表面形成薄层,并出现龟裂,可能是因为掺入SiO_2所致。     

ZnO/TiO_2-SiO_2的吸附脱硫条件和再生性能的探究

采用溶胶凝胶法制备不同Zn和Zr负载量的TiO_2-SiO_2,通过XRD进行表征,使用固定床流动法微型催化反应装置考察催化剂的性能。结果表明,ZnO和ZrO_2作为活性组分很好的分布在TiO_2-SiO_2载体上,负载ZnO的催化脱硫效果优于负载ZrO_2的,当ZnO的负载质量分数5%,TiO_2和SiO_2的摩尔比为1时,邻硝基氯苯的脱硫率可达到57.98%。加入的ZnO增加了载体的极性,对噻吩硫产生吸附作用,提高脱硫率。对失活的催化剂在450℃下煅烧,脱硫率维持在52%,达到了再生的目的。     

高盐度有机废水磁载催化剂降解工艺研究

以均匀沉淀法制备的Fe3O4磁粒为核心,以钛酸丁酯、正硅酸乙酯为原料,采用溶胶-凝胶法制备了磁载TiO2-SiO2-Fe3O4复合微粒,运用X射线衍射(XRD)、红外(IR)测试方法对所制得复合粒子进行表征,并以TiO2-SiO2-Fe3O4复合微粒为催化剂研究其高盐度有机废水催化降解的性能.结果表明,磁基体Fe3O4...     

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。     

Hydrodeoxygenation of stearic acid using Mo modified Ni and Co/alumina catalysts: Effect of calcination temperature

Abstract

The calcination temperature (Cal-Temp) plays a vital role in the performance of supported metal catalysts. In this work, the alumina supported Ni, NiMo, Co, and CoMo catalysts were prepared at different Cal-Temp. The catalysts were characterized by various techniques to identify the catalytically active different surface species to correlate their role in the hydrodeoxygenation of stearic acid. With increasing Cal-Temp, the metal dispersion was increased for Ni, NiMo, and CoMo catalyst (up to 973 K) and decreased for Co catalyst. With increasing Cal-Temp, the catalytic activity was thus increased for Ni and NiMo catalyst and decreased for Co catalyst. The activity of CoMo catalyst was, however, enhanced with rising Cal-Temp up to 973 K and declined slightly after that. The optimum Cal-Temp for Ni, NiMo, Co, and CoMo catalyst was found to be 1023 K, 973 K, 773 K, and 973 K. The reaction followed the decarbonylation route over active metallic centers (Ni and Co) and the HDO route over oxophilic M²⁺?MoO₂ (M = Ni/Co) and reducible cobalt oxide species. The C₁₇ alkane was thus the principal product over Ni catalyst, whereas C₁₈ alkane was the primary product over CoMo and NiMo catalyst. In contrast, both C₁₇ and C₁₈ alkanes were significant over Co catalyst.     

TiO2-SiO2复合氧化物的理化性质及其对柴油加氢精制性能的影响

采用溶胶-凝胶法结合CO₂超临界流体干燥技术制备了不同Ti/Si原子比的TiO₂-SiO₂复合氧化物（TS-n）,考察了Ti/Si原子比、焙烧温度对复合氧化物比表面积、孔结构、酸性及原子结合状态的影响,通过重油催化裂化柴油加氢精制反应考察了以TS-1、TS-4为载体的催化剂脱硫性能的差异.结果表明,TiO2经SiO2复合改性后,热稳定性和晶态稳定性大幅度提高;TiO₂-SiO₂复合氧化物的酸性及原子间的相互作用与Ti/Si原子比有直接的关系;载体的晶态组成及酸性和催化剂的酸性对催化剂的加氢脱硫性能有显著影响,复合氧化物中锐态型TiO₂的存在强化了载体与金属组分之间的相互作用,提高了催化剂的加氢脱硫活性,不同类型的酸性中心对柴油中不同类型的硫化物具有不同的脱除能力,Bronsted 酸中心较多的催化剂对结构简单的硫化物脱除能力强,Lewis酸中心较多的催化剂对结构复杂的硫化物有较好的脱除效果.     

The effect of nickel content on the hydrodeoxygenation of 4-methylphenol over unsupported NiMoW sulfide catalysts

Unsupported NiMoW sulfide hydrodeoxygenation (HDO) catalysts were prepared by mechanical activation method varying the nickel concentration. Catalysts were characterized by XRD, SEM, TEM and BET surface area measurements. Moreover, catalytic activity and selectivity were evaluated in the HDO of 4-methylphenol (4-MP). The results suggested that the structure and the promoting effects were strongly dependent on the amount of Ni added into the catalysts. Nickel gave a positive effect on HDO of 4-MP and modified the product selectivity slightly. It was also found that nickel played a crucial role in the variation of catalytic performance.     

载体对镍基催化剂催化氯代硝基苯加氢性能的影响

分别以碳纳米管(CNTs)、SiO<,2>、TiO<,2>、γ-Al<,2>O<,3>、TiO<,2>-SiO<,2>、SiO<,2>-TiO<,2>和活性炭(AC)为载体,以Ni、B为活性组分,采用浸渍-化学还原法制备了一系列负载型Ni-B非晶态合金催化剂,采用了电感耦合等离子体光谱、X-射线衍射、透射电子显微镜、差...     

TiO2及TiO2-SiO2复合氧化物特性及其降解水中有机污染物的光催化活性

TiO2 and TiO2-SiO2 photocatalysts were prepared by sol-gel and supercritical CO2 fluid drying method and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), etc. Their catalytic properties were tested through the photocatalytic degradation of phenol and aniline in wastewater. The results show that the developed fluidized photocatalytic reactor (FPR) and TiO2 catalyst had better performance in degrading pollutants as compared with slurry photocatalytic reactor (SPR) and commercial TiO2 catalyst. The composition and crystal form of TiO2-SiO2 composite oxide had obvious influence on catalytic effect and TiO2-SiO2 photocatalysts showed better catalytic activity and stability.     

TiO2及TiO2-SiO2复合氧化物特性及其降解水中有机污染物的光催化活性

TiO2 and TiO2-SiO2 photocatalysts were prepared by sol-gel and supercritical CO2 fluid drying method and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), etc. Their catalytic properties were tested through the photocatalytic degradation of phenol and aniline in wastewater. The results show that the developed fluidized photocatalytic reactor (FPR) and TiO2 catalyst had better performance in degrading pollutants as compared with slurry photocatalytic reactor (SPR) and commercial TiO2 catalyst. The composition and crystal form of TiO2-SiO2 composite oxide had obvious influence on catalytic effect and TiO2-SiO2 photocatalysts showed better catalytic activity and stability.