Ti-Si mixed oxides with different TiO2 content were prepared by sol-gel one step hydrolysis, using TiCl4 as the precursor. The samples were characterized by BET, FT-IR and XRD. The results indicated that titanium is...Ti-Si mixed oxides with different TiO2 content were prepared by sol-gel one step hydrolysis, using TiCl4 as the precursor. The samples were characterized by BET, FT-IR and XRD. The results indicated that titanium is in fourfold coordination with oxygen in the SiO44- in mixed oxides, form the bond of Ti-O-Si, and the low titania materials are mixed on an atomic scale. The phase of anatase appeared when TiO2 content is up to 80%. The mixed oxides had high specific surface areas up to 681.5 m2/g. 10TiSi is a better support than SiO2 in the reaction of CO oxidation.展开更多
The correlation between the catalytic activity and structure of Sn0.8Mo0.2 mixedoxides calcinated at diffrent temperatures has been investigated by using ESR, XPS and XRDtechniques. The results show that at 100～300 ...The correlation between the catalytic activity and structure of Sn0.8Mo0.2 mixedoxides calcinated at diffrent temperatures has been investigated by using ESR, XPS and XRDtechniques. The results show that at 100～300 ℃ molybdenum disperses on the surface ofrutile-type stannic oxide formed at 100℃, at 300～500℃ it gradually diffuses into SnO2 andat 550℃ the interstitial solid solution forms, which exhibites the best catalytic activity inoxidation of butene. The substitution solid solution forms at 600℃.展开更多
在分子氧-苯甲醛体系,由共沉淀法制备的Fe-Sn-O复合氧化物作为催化剂,催化分子氧化环己酮合成ε-己内酯,通过单因素实验,得到适宜的合成条件:常温常压下,以环己酮用量为5 mmol计;n(苯甲醛)∶n(环己酮)=3∶1;1,2-二氯乙烷20 m L;氧气流速...在分子氧-苯甲醛体系,由共沉淀法制备的Fe-Sn-O复合氧化物作为催化剂,催化分子氧化环己酮合成ε-己内酯,通过单因素实验,得到适宜的合成条件:常温常压下,以环己酮用量为5 mmol计;n(苯甲醛)∶n(环己酮)=3∶1;1,2-二氯乙烷20 m L;氧气流速20 m L/min;反应时间4 h;反应温度55°C.该条件下,ε-己内酯收率达到98.8%,选择性达到99.0%;采用SEM、XRD等对催化剂的结构进行表征;催化剂重复使用5次仍保持较高活性.展开更多
Sn-Ce-O binary catalysts with different Sn/Ce molar ratios were prepared with co-precipitation method and applied for CO and CH4 oxidation. The catalysts were characterized by means of Nz-BET, XRD and H2-TPR technique...Sn-Ce-O binary catalysts with different Sn/Ce molar ratios were prepared with co-precipitation method and applied for CO and CH4 oxidation. The catalysts were characterized by means of Nz-BET, XRD and H2-TPR techniques. It was found that for those Sn rich sam- pies such as SnCe91 and SnCe73, Ce cations were doped into the matrix of tetragonal rutile SnO2 to form SnO2-based solid solution. As a consequence, the oxidation activity as well as the thermal stability was significantly improved compared with pure SnO2. In contrast, for Ce rich samples such as SnCel9, SnCe37 and SnCe55, though the thermal stability was improved, the activity was worse than SnO2, due to the presence of much less amount of active oxygen species. Co-precipitation was found to be the best method to prepare Sn-Ce binary catalysts among all of the methods tried in this study.展开更多
文摘Ti-Si mixed oxides with different TiO2 content were prepared by sol-gel one step hydrolysis, using TiCl4 as the precursor. The samples were characterized by BET, FT-IR and XRD. The results indicated that titanium is in fourfold coordination with oxygen in the SiO44- in mixed oxides, form the bond of Ti-O-Si, and the low titania materials are mixed on an atomic scale. The phase of anatase appeared when TiO2 content is up to 80%. The mixed oxides had high specific surface areas up to 681.5 m2/g. 10TiSi is a better support than SiO2 in the reaction of CO oxidation.
文摘The correlation between the catalytic activity and structure of Sn0.8Mo0.2 mixedoxides calcinated at diffrent temperatures has been investigated by using ESR, XPS and XRDtechniques. The results show that at 100～300 ℃ molybdenum disperses on the surface ofrutile-type stannic oxide formed at 100℃, at 300～500℃ it gradually diffuses into SnO2 andat 550℃ the interstitial solid solution forms, which exhibites the best catalytic activity inoxidation of butene. The substitution solid solution forms at 600℃.
文摘在分子氧-苯甲醛体系,由共沉淀法制备的Fe-Sn-O复合氧化物作为催化剂,催化分子氧化环己酮合成ε-己内酯,通过单因素实验,得到适宜的合成条件:常温常压下,以环己酮用量为5 mmol计;n(苯甲醛)∶n(环己酮)=3∶1;1,2-二氯乙烷20 m L;氧气流速20 m L/min;反应时间4 h;反应温度55°C.该条件下,ε-己内酯收率达到98.8%,选择性达到99.0%;采用SEM、XRD等对催化剂的结构进行表征;催化剂重复使用5次仍保持较高活性.
文摘Sn-Ce-O binary catalysts with different Sn/Ce molar ratios were prepared with co-precipitation method and applied for CO and CH4 oxidation. The catalysts were characterized by means of Nz-BET, XRD and H2-TPR techniques. It was found that for those Sn rich sam- pies such as SnCe91 and SnCe73, Ce cations were doped into the matrix of tetragonal rutile SnO2 to form SnO2-based solid solution. As a consequence, the oxidation activity as well as the thermal stability was significantly improved compared with pure SnO2. In contrast, for Ce rich samples such as SnCel9, SnCe37 and SnCe55, though the thermal stability was improved, the activity was worse than SnO2, due to the presence of much less amount of active oxygen species. Co-precipitation was found to be the best method to prepare Sn-Ce binary catalysts among all of the methods tried in this study.
