A core-shell HZSM-5@SBA-15 composite was prepared by the acidic sol-gel coating method using Pluronic P123 as the template. Its structure, properties, and catalytic performance in the conversion of methanol to aromati...A core-shell HZSM-5@SBA-15 composite was prepared by the acidic sol-gel coating method using Pluronic P123 as the template. Its structure, properties, and catalytic performance in the conversion of methanol to aromatics(MTA) were compared with HZSM-5@SiO_2. The silica shells of these two samples can both reduce the acid sites of HZSM-5, and consequently can decrease the formation of coke on the catalyst. However, in the ordered mesoporous SBA-15 shell the aromatics and the coke precursors could diffuse more effectively than in the amorphous SiO_2 shell; therefore, in the MTA reaction catalyzed by HZSM-5@SBA-15 composite a higher BTX selectivity and a longer catalyst cycle length were observed. The cycle length of HZSM-5@SBA-15 was by 50 h longer than that of HZSM-5@SiO_2, and under this situation the selectivity of BTX still reached 56%.展开更多
Photocatalysis is one of the most promising methods owing to its great potential to relieve environmental issue. To construct efficient photocatalyst with low energy consumption, mild catalytic conditions, and stable ...Photocatalysis is one of the most promising methods owing to its great potential to relieve environmental issue. To construct efficient photocatalyst with low energy consumption, mild catalytic conditions, and stable chemical properties are highly desired. In this work, a novel, highly active and environmental friendly mesoporous photocatalyst Bi4O5Br2/SBA-15 was synthesized by hydrothermal method, and its characteristics and visible-light catalytic activity were investigated. The synthesized photocatalyst consisted of Langmuir type IV hysteresis loops, which was confirmed to be a composite material with mesoporous structure. It exhibited a high visible-light absorption intensity and a low recombination rate of photo-generated electrons and holes. When the mass ratio of Bi/SiO2 was 30/100 during the synthesis, the obtained photocatalyst (Bi30/SBA-15) reflected the fastest Rhodamine B (RhB) removal rate and achieved 100% decolorization of RhB by both adsorption and degradation process. This high decolorization efficiency can also be maintained and realized by recycling the used composite in practice. The enhanced visible-light photocatalytic activity of novel Bi4O5Br2/SBA-15 photocatalyst can be ascribed to the existing active sites both inside and outside SBA-15 which enhanced the separation of photo-generated electrons and holes.展开更多
采用后合成法合成了ZSM-5–SBA-15微介孔复合分子筛,考察了m(ZSM-5)/m(SBA-15)、晶化时间、盐酸量、焙烧温度对烷基化催化性能的影响。在m(ZSM-5)/m(SBA-15)=0.2,晶化时间为18 h,盐酸量为20 m L,焙烧温度为550℃条件下,合成的复合分子...采用后合成法合成了ZSM-5–SBA-15微介孔复合分子筛,考察了m(ZSM-5)/m(SBA-15)、晶化时间、盐酸量、焙烧温度对烷基化催化性能的影响。在m(ZSM-5)/m(SBA-15)=0.2,晶化时间为18 h,盐酸量为20 m L,焙烧温度为550℃条件下,合成的复合分子筛催化剂的甲醇转化率为94.93%,对二甲苯选择性为45.46%。惰性SBA-15介孔分子筛抑制了ZSM-5外表面酸性,提高了对二甲苯的选择性。展开更多
基金supported by the Program for Liaoning Excellent Talents in Universities,abbreviated as "LNET" (LJQ2015062)the Program for Science and Technology Agency of Liaoning Province (20170540585)+1 种基金the General Scientific Research Project of Liaoning Provincial Department of Education (L2015296, L2016018)the Science and Technology Planning Project of Fushun (FSKJHT201376)
文摘A core-shell HZSM-5@SBA-15 composite was prepared by the acidic sol-gel coating method using Pluronic P123 as the template. Its structure, properties, and catalytic performance in the conversion of methanol to aromatics(MTA) were compared with HZSM-5@SiO_2. The silica shells of these two samples can both reduce the acid sites of HZSM-5, and consequently can decrease the formation of coke on the catalyst. However, in the ordered mesoporous SBA-15 shell the aromatics and the coke precursors could diffuse more effectively than in the amorphous SiO_2 shell; therefore, in the MTA reaction catalyzed by HZSM-5@SBA-15 composite a higher BTX selectivity and a longer catalyst cycle length were observed. The cycle length of HZSM-5@SBA-15 was by 50 h longer than that of HZSM-5@SiO_2, and under this situation the selectivity of BTX still reached 56%.
基金supported by the National Natural Science Foundations of China(21476132,51536009,51406109 and 21506118)National High Technology Research and Development Program of China(863 program,2012AA101808)~~
文摘Photocatalysis is one of the most promising methods owing to its great potential to relieve environmental issue. To construct efficient photocatalyst with low energy consumption, mild catalytic conditions, and stable chemical properties are highly desired. In this work, a novel, highly active and environmental friendly mesoporous photocatalyst Bi4O5Br2/SBA-15 was synthesized by hydrothermal method, and its characteristics and visible-light catalytic activity were investigated. The synthesized photocatalyst consisted of Langmuir type IV hysteresis loops, which was confirmed to be a composite material with mesoporous structure. It exhibited a high visible-light absorption intensity and a low recombination rate of photo-generated electrons and holes. When the mass ratio of Bi/SiO2 was 30/100 during the synthesis, the obtained photocatalyst (Bi30/SBA-15) reflected the fastest Rhodamine B (RhB) removal rate and achieved 100% decolorization of RhB by both adsorption and degradation process. This high decolorization efficiency can also be maintained and realized by recycling the used composite in practice. The enhanced visible-light photocatalytic activity of novel Bi4O5Br2/SBA-15 photocatalyst can be ascribed to the existing active sites both inside and outside SBA-15 which enhanced the separation of photo-generated electrons and holes.
文摘采用后合成法合成了ZSM-5–SBA-15微介孔复合分子筛,考察了m(ZSM-5)/m(SBA-15)、晶化时间、盐酸量、焙烧温度对烷基化催化性能的影响。在m(ZSM-5)/m(SBA-15)=0.2,晶化时间为18 h,盐酸量为20 m L,焙烧温度为550℃条件下,合成的复合分子筛催化剂的甲醇转化率为94.93%,对二甲苯选择性为45.46%。惰性SBA-15介孔分子筛抑制了ZSM-5外表面酸性,提高了对二甲苯的选择性。
