共查询到20条相似文献,搜索用时 203 毫秒
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采用溶胶凝胶-水热法制备Cu/TiO2-SiO2催化剂,并运用XRD、BET对催化剂进行表征,以糠醛选择加氢制糠醇反应为探针,考察载体组成及Cu含量对催化剂活性的影响。结果表明,载体中引入适量的TiO2能够抑制Cu晶粒的增长,改善Cu粒子在催化剂中的分散性。载体中TiO2质量分数40%,Cu负载量(质量分数)20%时,制备的Cu/TiO2-SiO2催化剂具有较好的催化活性。 相似文献
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二氧化硅-磺酸催化制备生物柴油的研究 总被引:1,自引:0,他引:1
通过溶胶-凝胶法制备二氧化硅,进而与氯磺酸反应制得二氧化硅-磺酸(SiO2-SO3H)固体酸催化剂,用于大豆油与乙醇的酯交换反应制备生物柴油,考察了催化剂的处理温度、乙醇与大豆油的摩尔比、催化剂用量、原料油油酸含量和反应时间的影响.结果表明,二氧化硅-磺酸(SiO2-SO3H)具有较高的酯交换反应催化活性.制备生物柴油的最佳条件如下:催化剂处理温度为120℃、醇油摩尔比为6∶1、催化剂质量分数为5.0%(以大豆油计)、正庚烷的质量分数(以大豆油计)为30.0%、反应时间为6.0 h,此时生物柴油产率可达97.84%.与固体碱催化剂相比,固体酸催化剂对原料的酸度有更强的适应性. 相似文献
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《无机盐工业》2017,(8)
以非淬水高镁炉渣为原料,采用硝酸对其进行酸解处理,通过调节炉渣滤液中的pH,沉淀回收其中的铁,并制成Fe_2O_3产品。采用红外光谱对Fe_2O_3进行定性分析,采用X射线荧光光谱仪对炉渣组成和Fe_2O_3含量进行分析。系统性考察了硝酸质量分数、酸解温度、酸解时间、pH以及氢氧化钠质量分数对炉渣中Fe回收利用的影响。结果表明该回收利用工艺是可行的。回收利用非淬水高镁炉渣中的铁制备Fe_2O_3的工艺条件:硝酸质量分数为60%、酸解温度为60℃、酸解时间为50 min、pH为8.6、氢氧化钠质量分数为20%。在以上工艺条件下,炉渣粉末为20 g时Fe_2O_3产量为0.86 g,Fe_2O_3纯度达到93.6%。 相似文献
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以高比表面积无定形硅铝(ASA)和改性Y型分子筛(USY)为原料制备催化剂载体,分别采用传统浸渍法、铝溶胶浸渍法、USY粉体浸渍法和ASA粉体浸渍法制备Ni-W/Y-ASA催化剂。采用氮气吸附-脱附、扫描电镜(SEM)、氨气程序升温脱附(NH3-TPD)、吸附吡啶原位红外(Py-IR)和颗粒强度测定仪等表征手段,探究不同的浸渍方法对催化剂的织构性质、形貌、酸性以及机械强度的影响,并将制备的催化剂应用于正癸烷的加氢裂化反应。结果表明,采用ASA粉体浸渍方法,因较多地保留了Ni-W/Y-ASA催化剂中USY粉体上的B酸性位,使催化剂具有最多的B酸含量,增强了催化剂的酸性质,进而提高了催化剂在以正癸烷为模型化合物的加氢裂化反应中的裂化活性。 相似文献
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采用N2吸附法、IR和XRD等手段研究了活性氧化铝用于催化裂化(FCC )催化剂中的性能。结果表明,在FCC催化剂制备及应用条件下,活性氧化铝保持比较稳定的比表面积、孔容和酸性等性能。磷易与活性氧化铝作用,分子筛与磷的作用存在一个逐步平衡的过程;氧化铝有利于改善基质的孔结构;对以铝溶胶为粘结剂制备的催化剂进行磷改性处理,催化剂基质与活性组分分子筛上的磷含量基本相当。 相似文献
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An excellent support of Pd catalyst for methane combustion: Thermal-stable Si-doped alumina 总被引:1,自引:0,他引:1
Xiaohong Wang Yun Guo Guanzhong Lu Yu Hu Liangzhu Jiang Yanglong Guo Zhigang Zhang 《Catalysis Today》2007,126(3-4):369-374
Thermal-stable Si-doped alumina was prepared by the reverse microemulsion method and was used as the support of Pd catalyst for the methane combustion. The physicochemical properties of Si-alumina and catalytic performance of Pd/Si-Al2O3 were characterized by XRD, N2 adsorption, FT-IR, XPS and methane catalytic combustion. The results indicate that the presence of Si can increase the thermal stability of alumina and promote the coordination state of aluminum from tetrahedral to octahedral, but its content added should be controlled appropriately to 5–6 wt%. Si-doped alumina prepared by the reverse microemulsion method is an excellent support of Pd catalyst for the methane combustion, which can increase both the catalytic activity and thermal stability of the Pd catalyst. The studies also show that the calcination temperature of support affects remarkably the performance of catalyst, and the high thermal stability of support is very important to increase the performance of Pd catalyst for the methane combustion. 相似文献
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PVA作纺丝助剂制备莫来石-氧化铝长纤维 总被引:1,自引:0,他引:1
用氯化铝和铝粉为原料制备了铝溶胶,再向铝溶胶加入硅溶胶、封端剂和聚乙烯醇(PVA)纺丝助剂,制得莫来石-氧化铝溶胶,研究了纺丝助剂加入量对溶胶纺丝性能的影响。研究发现,溶胶在浓缩时,胶粒间发生缩合反应,形成线性或非线性的分子链,生成可纺的黏性溶胶;在溶胶中加入纺丝助剂,铝/硅离子或胶粒与纺丝助剂的活性基团发生缩聚反应,生成有机-无机的杂化分子链,提高了溶胶的纺丝性能;在加入封端剂的同时,加入质量分数为1%的PVA,凝胶纤维的最大长度可达100 cm。凝胶纤维在1 200 ℃下烧结1 h后,得到的陶瓷纤维的物相为γ-Al2O3和莫来石相,纤维表面光滑、直径均匀。 相似文献
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采用喷雾分散-油柱成型制备方法,以硅溶胶为硅源,制备不同含量SiO2掺杂改性的微球形氧化铝载体,研究SiO2含量对氧化铝载体结构及以其为载体的负载型催化剂性能的影响。研究表明,通过掺杂SiO2有效改善了氧化铝微球的热稳定性,且氧化铝载体的孔容、比表面积及酸中心数量均随SiO2含量的增加而增加,孔径随SiO2含量的增加而减小。Pd/SiO2-Al2O3催化剂结构表征及流化床蒽醌加氢性能评价结果表明,掺杂SiO2质量分数6%时,Pd/SiO2-Al2O3催化剂氢化效率大于12.5g·L^-1,选择性大于98.3%。 相似文献
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Optimization of Effective Sol‐Gel Parameters for the Synthesis of Mesoporous γ‐Al2O3 Using Experimental Design 下载免费PDF全文
Mesoporous nanocrystalline γ‐alumina was prepared by a template‐free sol‐gel method using aluminum ethoxide as precursor. Significant parameters, such as the water/aluminum ethoxide molar ratio, the pH of the solution, and the time and temperature of aging, were optimized by the Taguchi method to obtain γ‐alumina with a high surface area and pore volume. The influences of the main parameters on the catalytic performance of the prepared catalysts were investigated via dehydration of methanol to dimethyl ether in a fixed‐bed reactor. The catalysts were characterized by X‐ray diffraction, N2 adsorption‐desorption, ammonia temperature‐programmed desorption, and scanning electron microscopy techniques. The results show that the aging temperature had a significant influence on the catalyst performance. 相似文献
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基于KCl-NaCl-AlF3熔盐体系,采用氢氧化铝为铝源、以氯化钾(KCl)和氯化钠(NaCl)复合熔盐为反应介质、以氟化铝(AlF3)为添加剂制备片状α-Al2O3。通过X射线衍射和扫描电子显微镜表征方法研究了氟化铝含量、煅烧温度和保温时间对片状氧化铝形貌和晶型的影响。结果表明,当氟化铝添加量(氟化铝与氢氧化铝的质量比)为5%、煅烧温度为750 ℃、保温时间为180 min时,可获得片状α-Al2O3,其径向尺寸约为5.1 μm,径厚比达18,分散性良好。 相似文献
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Jolanta R. Grzechowiak Iwona Wereszczako-Zieliska Karolina Mroziska 《Catalysis Today》2007,119(1-4):23-30
Alumina–titania supports containing 5–50 wt.% of TiO2 were prepared by coprecipitation method using inorganic precursors (sodium aluminate and titanium chloride). DTA-TGA, XRD, SEM, TPDNH3, and IR spectroscopy were used to characterise these materials. The study shows that the promoting effect of nickel on the HDS activity of molybdenum catalysts supported on Al2O3TiO2 is significantly lower than that for molybdenum catalyst supported on Al2O3, and depends on the TiO2 content. The SEM results show that in the case of rich Al support (20 wt.% of TiO2) molybdenum was aggregated on the external surface of the catalyst, whereas it was uniformly dispersed on the external surface of alumina. Results also show that molybdenum is preferably supported on aluminum oxide. Application of Al2O3TiO2 oxides enhances the HDN activity of nickel–molybdenum catalysts. The highest HDN efficiency was obtained for the NiMo/Al2O3TiO2 catalyst containing 50 wt.% of TiO2. HDN activity was found to depend on protonic acidity and anatase content. 相似文献