期刊文献+
共找到3篇文章
< 1 >
每页显示 20 50 100
H-MCM-22沸石分子筛中Brnsted/Lewis酸协同效应的~1H和^(27)Al双量子魔角旋转固体核磁共振研究 被引量:5
1
作者 喻志武 王强 +1 位作者 陈雷 邓风 《催化学报》 SCIE CAS CSCD 北大核心 2012年第1期129-139,共11页
采用各种固体核磁共振 (NMR) 技术详细研究了 H-MCM-22 分子筛中 Brnsted/Lewis 酸的协同效应. 二维 1H 双量子魔角旋转 (DQ-MAS) NMR 结果表明, 在脱铝 H-MCM-22 分子筛中 Brnsted 酸位 (骨架桥式羟基) 和 Lewis 酸位 (非骨架铝羟基) ... 采用各种固体核磁共振 (NMR) 技术详细研究了 H-MCM-22 分子筛中 Brnsted/Lewis 酸的协同效应. 二维 1H 双量子魔角旋转 (DQ-MAS) NMR 结果表明, 在脱铝 H-MCM-22 分子筛中 Brnsted 酸位 (骨架桥式羟基) 和 Lewis 酸位 (非骨架铝羟基) 之间是空间邻近的, 暗示着可能存在 B/L 酸协同效应. 二维 27Al DQ-MAS NMR 结果揭示了各种铝物种之间的空间邻近性, 表明 B/L 酸协同效应优先发生在 H-MCM-22 分子筛超笼中的骨架 T6 位铝和非骨架铝物种之间. 2-13C-丙酮探针分子实验发现, 因 B/L 酸协同效应而导致脱铝 H-MCM-22 分子筛酸性明显增强, 氘代吡啶探针分子实验也证实在 H-MCM-22 分子筛的超笼中发生了 B/L 酸协同效应. 上述结果将有助于我们理解在脱铝 H-MCM-22 分子筛上发生的多相催化机理. 展开更多
关键词 H-MCM-22 分子筛 脱铝 Brnsted/Lewis 酸协同效应 双量子魔角旋转核磁共振
下载PDF
Synergistic effects in N‐K_2Ti_4O_9/UiO‐66‐NH_2 composites and their photocatalysis degradation of cationic dyes 被引量:2
2
作者 李孙峰 王幸 +6 位作者 何琴琴 陈琪 徐艳丽 杨汉标 吕盟盟 魏凤玉 刘雪霆 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第3期367-377,共11页
N-K2Ti4O9/UiO-66-NH2 composites synthesized by a facile solvothermal method have a core-shell structure with UiO-66-NH2 forming the shell around a N-K2Ti4O9 core.Their photocatalytic activities in the degradation of d... N-K2Ti4O9/UiO-66-NH2 composites synthesized by a facile solvothermal method have a core-shell structure with UiO-66-NH2 forming the shell around a N-K2Ti4O9 core.Their photocatalytic activities in the degradation of dyes under visible light irradiation were investigated.The N-K2Ti4O9/UiO-66-NH2 composites exhibited higher photocatalytic activity than the pure components.This synergistic effect was due to the high adsorption capacity of UiO-66-NH2 and that the two components together induced an enhanced separation efficiency of photogenerated electron-hole pairs.The mass ratio of N-K2Ti4O9 to ZrCl4 of 3:7 in the composite exhibited the highest photocatalytic activity.Due to the electrostatic attraction between the negatively charged backbone of UiO-66-NH2with the positively charged groups of cationic dyes,the composites were more photocatalytically active for cationic dyes than for anionic dyes. 展开更多
关键词 Nitrogen-doped potassium titamate UiO-66-NH2 Selective photocatalysis Synergistic effect Composite
下载PDF
Synergistic effect of additives on electrodeposition of copper from cyanide-free electrolytes and its structural and morphological characteristics 被引量:8
3
作者 R.SEKAR 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第7期1665-1676,共12页
Electrodeposition of acid copper plating on mild steel substrate is tedious due to the galvanic displacement reaction ofcopper on mild steel.This can be avoided by using a proper complexing agent,because the complexin... Electrodeposition of acid copper plating on mild steel substrate is tedious due to the galvanic displacement reaction ofcopper on mild steel.This can be avoided by using a proper complexing agent,because the complexing agent tuned the potential ofnoble direction to less noble direction by complex formation.In this paper,environment friendly electrodeposition of copper fromnon-cyanide electrolyte using sodium gluconate as complexing agent was investigated in alkaline medium.The effects of additivessuch as1,2,3-benzotriazole,sodium lauryl sulphate,PEG8000and saccharin were studied.These additives are found to reduce thegrain size,grain boundaries and improve surface morphology of the copper deposits.Also they improve the throwing power of thedepositing electrolytes and hardness of deposits.The electrodeposited copper coatings were characterized by X-ray diffractiontechnique.XRD results indicate that the electrodeposited copper shows polycrystalline and face centered cubic structure.The crystalsize was calculated by XRD and AFM analysis.Among these additives studied,the mixture of benzotriazole and sodium laurylsulphate acts as the best additive.A uniform pore-free surface observed under SEM and AFM results reveal the grain refining broughtabout by the additives. 展开更多
关键词 synergistic effect GLUCONATE ADDITIVE atomic force microscopy ELECTRODEPOSITION COPPER
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部