以水杨酸为模板剂和还原剂,采用水热法制备得到了一种MoO3纳米带/RGO复合材料。利用XRD、SEM、TEM、拉曼光谱、恒流充放电、交流阻抗等手段对样品的结构、形貌以及电化学性能进行表征。测试结果表明,MoO3纳米带/RGO复合材料作为锂离子...以水杨酸为模板剂和还原剂,采用水热法制备得到了一种MoO3纳米带/RGO复合材料。利用XRD、SEM、TEM、拉曼光谱、恒流充放电、交流阻抗等手段对样品的结构、形貌以及电化学性能进行表征。测试结果表明,MoO3纳米带/RGO复合材料作为锂离子电池负极材料,在50 m A·g-1的电流密度下可逆比容量为1 000 m Ah·g-1,循环50次后比容量还保持在950 m Ah·g-1,相比于MoO3纳米带其容量保持能力和循环性能得到了显著改善。展开更多
A mesoporous(d=2.3mm)silica-pillared layered tetratita nate with a super gallery(d 001 =1.84mm)was prepared by first preswelling layered tetratitanate with n-dodecyl amine,then reacting with 20wt%NH 2 (CH 2 ) 3 Si (OC...A mesoporous(d=2.3mm)silica-pillared layered tetratita nate with a super gallery(d 001 =1.84mm)was prepared by first preswelling layered tetratitanate with n-dodecyl amine,then reacting with 20wt%NH 2 (CH 2 ) 3 Si (OC 2 H 5 ) 3 aqueous solution,and finally calcinating the resultant solid product i n air at 550℃.All the reaction was carried out hydrothermally in an aut oclave at 130℃.The obtained materia l has a relatively high BET surface area of204m 2 ·g -1 and a thermal stability beyond 600℃.The catalytic application of the material was also investigated by using the dehydration of isopropanol and the reform of n-hexane as two probing reactions.展开更多
以不同硅/铝摩尔比(简称硅/铝比)的HZSM-5分子筛作为研究对象,通过氨气吸附及程序升温脱附(NH_(3)-TPD)、烷烃吸附及程序升温脱附(Alkane-TPD)、29Si和27Al魔角转动固体核磁共振(29Si&27Al MAS SSNMR)、^(1)H和^(1)H双量子魔角转动...以不同硅/铝摩尔比(简称硅/铝比)的HZSM-5分子筛作为研究对象,通过氨气吸附及程序升温脱附(NH_(3)-TPD)、烷烃吸附及程序升温脱附(Alkane-TPD)、29Si和27Al魔角转动固体核磁共振(29Si&27Al MAS SSNMR)、^(1)H和^(1)H双量子魔角转动固体核磁共振(^(1)H&^(1)H DQ MAS SSNMR)等表征手段,研究了HZSM-5分子筛中Brønsted(B)酸中心的空间邻近性对烷烃分子吸附的特点,同时考察了空间邻近的B酸中心对烷烃单分子裂解选择性的影响。结果表明,随着HZSM-5分子筛硅/铝比的降低,分子筛中B酸中心空间邻近的几率增加,烷烃(丙烷、正丁烷和正戊烷)裂解的反应路径、选择性在邻近的B酸中心都与在孤立的酸中心上不同,显示出协同催化特点。其中,烷烃转化过程中裂解反应增加,脱氢反应减少,中间裂解产物相比于端基裂解产物具有更高的选择性。展开更多
综述了燃料油(主要是汽油和柴油)深度加氢脱硫催化剂的研究进展。汽油精制的主要问题是在深度加氢脱硫的同时减少由于烯烃饱和造成的辛烷值损失;柴油深度加氢脱硫主要是脱除其中的难脱除硫化物及稠环芳烃加氢饱和。TiO_2和 ZrO_2等载体...综述了燃料油(主要是汽油和柴油)深度加氢脱硫催化剂的研究进展。汽油精制的主要问题是在深度加氢脱硫的同时减少由于烯烃饱和造成的辛烷值损失;柴油深度加氢脱硫主要是脱除其中的难脱除硫化物及稠环芳烃加氢饱和。TiO_2和 ZrO_2等载体负载的金属硫化物催化剂比传统加氢脱硫催化剂的活性高。助剂 P 和 F 能减弱载体-金属间相互作用,在 Co(Ni)-Mo(W)/γ-Al_2O_3催化剂中生成更多的高活性Ⅱ型中心。螯合剂能延迟 Co 的硫化,有利于 Co-Mo-S 活性中心的生成。过渡金属磷化物催化剂表现出更高的脱硫、脱氮活性及良好的活性稳定性,它的主要缺点是金属磷化物的分散度较差,活性中心数目较少。过渡金属碳化物和氮化物催化剂对脱硫、脱氮的初活性较高,但使用后表面金属被硫化,催化活性下降。展开更多
A new biodegradable PtBA-PHB-PtBA triblock copolymer was successfully synthesized by ATRP method with Br-PHB-Br as macroinitiator,tert-butyl acrylate as monomer and CuBr/PMDETA as the catalyst system.Cleavage of the t...A new biodegradable PtBA-PHB-PtBA triblock copolymer was successfully synthesized by ATRP method with Br-PHB-Br as macroinitiator,tert-butyl acrylate as monomer and CuBr/PMDETA as the catalyst system.Cleavage of the tert-butyl ether groups of the PtBA-PHB-PtBA triblock copolymer was then performed via hydrolysis with trifluoroacetic acid as the catalyst in dichloromethane to afford the amphiphilic PAA-PHB-PAA triblock copolymer.The hydrolysis is successful but trace tert-butyl ether groups still remain in the backbone.The molecular weight characteristics and chain structures were conformed by GPC and NMR,respectively.Because of hydrophilic and biocompatibility,the amphiphilic triblock copolymers have potential applications in the field of drug release.展开更多
文摘以水杨酸为模板剂和还原剂,采用水热法制备得到了一种MoO3纳米带/RGO复合材料。利用XRD、SEM、TEM、拉曼光谱、恒流充放电、交流阻抗等手段对样品的结构、形貌以及电化学性能进行表征。测试结果表明,MoO3纳米带/RGO复合材料作为锂离子电池负极材料,在50 m A·g-1的电流密度下可逆比容量为1 000 m Ah·g-1,循环50次后比容量还保持在950 m Ah·g-1,相比于MoO3纳米带其容量保持能力和循环性能得到了显著改善。
文摘A mesoporous(d=2.3mm)silica-pillared layered tetratita nate with a super gallery(d 001 =1.84mm)was prepared by first preswelling layered tetratitanate with n-dodecyl amine,then reacting with 20wt%NH 2 (CH 2 ) 3 Si (OC 2 H 5 ) 3 aqueous solution,and finally calcinating the resultant solid product i n air at 550℃.All the reaction was carried out hydrothermally in an aut oclave at 130℃.The obtained materia l has a relatively high BET surface area of204m 2 ·g -1 and a thermal stability beyond 600℃.The catalytic application of the material was also investigated by using the dehydration of isopropanol and the reform of n-hexane as two probing reactions.
文摘以不同硅/铝摩尔比(简称硅/铝比)的HZSM-5分子筛作为研究对象,通过氨气吸附及程序升温脱附(NH_(3)-TPD)、烷烃吸附及程序升温脱附(Alkane-TPD)、29Si和27Al魔角转动固体核磁共振(29Si&27Al MAS SSNMR)、^(1)H和^(1)H双量子魔角转动固体核磁共振(^(1)H&^(1)H DQ MAS SSNMR)等表征手段,研究了HZSM-5分子筛中Brønsted(B)酸中心的空间邻近性对烷烃分子吸附的特点,同时考察了空间邻近的B酸中心对烷烃单分子裂解选择性的影响。结果表明,随着HZSM-5分子筛硅/铝比的降低,分子筛中B酸中心空间邻近的几率增加,烷烃(丙烷、正丁烷和正戊烷)裂解的反应路径、选择性在邻近的B酸中心都与在孤立的酸中心上不同,显示出协同催化特点。其中,烷烃转化过程中裂解反应增加,脱氢反应减少,中间裂解产物相比于端基裂解产物具有更高的选择性。
文摘综述了燃料油(主要是汽油和柴油)深度加氢脱硫催化剂的研究进展。汽油精制的主要问题是在深度加氢脱硫的同时减少由于烯烃饱和造成的辛烷值损失;柴油深度加氢脱硫主要是脱除其中的难脱除硫化物及稠环芳烃加氢饱和。TiO_2和 ZrO_2等载体负载的金属硫化物催化剂比传统加氢脱硫催化剂的活性高。助剂 P 和 F 能减弱载体-金属间相互作用,在 Co(Ni)-Mo(W)/γ-Al_2O_3催化剂中生成更多的高活性Ⅱ型中心。螯合剂能延迟 Co 的硫化,有利于 Co-Mo-S 活性中心的生成。过渡金属磷化物催化剂表现出更高的脱硫、脱氮活性及良好的活性稳定性,它的主要缺点是金属磷化物的分散度较差,活性中心数目较少。过渡金属碳化物和氮化物催化剂对脱硫、脱氮的初活性较高,但使用后表面金属被硫化,催化活性下降。
文摘A new biodegradable PtBA-PHB-PtBA triblock copolymer was successfully synthesized by ATRP method with Br-PHB-Br as macroinitiator,tert-butyl acrylate as monomer and CuBr/PMDETA as the catalyst system.Cleavage of the tert-butyl ether groups of the PtBA-PHB-PtBA triblock copolymer was then performed via hydrolysis with trifluoroacetic acid as the catalyst in dichloromethane to afford the amphiphilic PAA-PHB-PAA triblock copolymer.The hydrolysis is successful but trace tert-butyl ether groups still remain in the backbone.The molecular weight characteristics and chain structures were conformed by GPC and NMR,respectively.Because of hydrophilic and biocompatibility,the amphiphilic triblock copolymers have potential applications in the field of drug release.
