H. N. Hareesh
,
K. U. Minchitha
,
N. Nagaraju
,
N. Kathyayini
催化学报
doi:10.1016/S1872-2067(15)60964-0
采用浸渍法制备了多壁碳纳米管(MWCNT)负载的Cu2O和CuI催化剂,并运用粉末X射线衍射、红外光谱、扫描电镜-能量散射谱、透射电镜和NH3程序升温脱附等技术对催化剂进行了表征。结果表明,催化剂中沉积的Cu2O和CuI分别以立方相和γ相存在于MWCNT上,且表现出由弱到强的拉电子(Lewis酸)性能。将催化剂用于催化芳醛与2-氨基吡啶氧化酰胺化反应合成N-(吡啶-2-基)苯酰胺类化合物,产物选择性为100%,收率为50%–95%。 CuI/MWCNT催化剂上产物分离收率性能好于Cu2O/MWCNT,但后者的循环使用性能更好。与共价的CuI相比,离子化的Cu2O与极性的酸活化的MWCNT间具有更适宜的相互作用,这种不同的相互作用可显著影响2-氨基吡啶的氨基对芳醛羰基的亲核进攻速率。
关键词:
氧化亚铜
,
碘化铜
,
多壁碳纳米管
,
2-氨基吡啶
,
氧化酰胺化
Journal of Physical Chemistry C
The Li-Mg-N-H system was prepared by reacting magnesium amide [Mg(NH(2))(2)] with lithium nitride (Li(3)N) and investigated with regard to the hydrogen storage properties. Our study shows that the present method is superior to the conventional route in enhancing the reversible dehydrogenation properties. Through optimizing the Li(3)N:Mg(NH(2))(2) ratio in the starting materials, the reversible capacity of U-Mg-N-H system increases to 4.9 wt %, 18% higher than that typically obtained from the Mg(NH(2))(2) + 2LiH mixture at 200 degrees C. Furthermore, increasing the Li(3)N:Mg(NH(2))(2) ratio is effective for mitigating the ammonia release from thus-prepared samples. Combined property/structure investigations indicate that the obtained enhancements should be ascribed to the effects of LiNH(2) and LiH that were in situ generated from the excess Li(3)N. LiNH(2) may promote the dehydrogenation reaction via seeding the reaction intermediate. The concurrently generated LiH acts as an effective ammonia trapping agent. These findings highlight the potential of "intermediate seeding" as a strategy to enhance the reversible hydrogen storage properties of metal-N-H systems.
关键词:
complex hydrides;ultrafast reaction;amide;improvement;desorption;linh2;destabilization;mechanism;mixtures;imides
李建权
,
程平
,
王鸿梅
,
王占新
,
储焰南
,
周士康
量子电子学报
doi:10.3969/j.issn.1007-5461.2004.03.005
在流动余辉质谱装置上,利用He的空心阴极放电产物与H2O反应制备了反应物离子H3O+(H2O)n(n=0～4),并观察了H3O+(H2O)n(n=0～4)与CH3OH、C2H5OH反应的产物离子,对它们进行了归属,分析了各种产物离子形成的离子-分子反应机制.
关键词:
光谱学
,
流动余辉质谱
,
甲醇
,
乙醇
万永中
,
张志明
,
沈荷生
,
何贤昶
,
张卫
,
王季陶
无机材料学报
doi:10.3321/j.issn:1000-324X.1999.06.002
通过热力学分析从理论计算上给出了C-H-N体系中低压生长金刚石的三元相图.该相图中存在金刚石生长区.不同温度和压强下金刚石生长区几乎都位于CH4-N连线以下,并且随衬底温度的改变而有显著的变化.随着氮含量的增加,金刚石生长区向碳含量减少的方向移动.使用该相图对优化添加含氮气源生长金刚石的实验条件提供了理论依据.
关键词:
金刚石
,
含氮气源
,
相图
,
化学气相淀积
Journal of Materials Research
The effect of Li(3)N additive on the Li-Mg-N-H system was examined with respect to the reversible dehydrogenation performance. Screening Study with varying Li(3)N additions (5, 10, 20, and 30 mol%) demonstrates that all are effective for improving the hydrogen desorption capacity. Optimally, incorporation of 10 mol% Li(3)N improves the practical capacity from 3.9 wt% to approximately 4.7 wt% hydrogen at 200 degrees C, which drives the dehydrogenation reaction toward completion. Moreover, the capacity enhancement persists well over 10 de-/rehydrogenation cycles. Systematic x-ray diffraction examinations indicate that Li(3)N additive transforms into LiNH(2) and LiH phases and remains during hydrogen cycling. Combined structure/property investigations suggest that the LiNH(2) "seeding" should be responsible for the capacity enhancement, which reduces the kinetic barrier associated with the nucleation of intermediate LiNH(2). In addition, the concurrent incorporation of LiH is effective for mitigating the ammonia release.
关键词:
complex hydrides;improvement;mixtures;imides;amide;h-2
余迎新
,
张少峰
,
宋海斌
人工晶体学报
doi:10.3969/j.issn.1000-985X.2004.03.025
在中温水热条件下,利用醋酸镉和3-(3-吡啶基)丙烯酸反应,合成了一种新型的二维配位聚合物[Cd(C8H7NO2)2]n.对其进行了元素分析、红外光谱表征和X射线单晶衍射测定.该配位聚合物属三斜晶系,P-1空间群,晶胞参数为:a=0.5031(2)nm,b=0.8109(3)nm,c=0.9531(4)nm,α=69.411(6)°,β=80.554(6)°,γ=76.020(7)°,V=0.3519(2)nm3,Z=1,dc=1.929g/cm3,μ=1.575 mm-1,F(000)=202,R1=0.0313,wR2=0.0641.
关键词:
二维配位聚合物
,
水热合成
,
晶体结构
胡义华
,
刘美希
,
陈丽
,
王小涓
,
储焰南
,
曹德兆
量子电子学报
doi:10.3969/j.issn.1007-5461.2001.04.008
本文在流动余辉装置上,研究了亚稳态He(23S)原子与N2H4分子碰撞传能,观察到了激发态产物NH(A3II→X3∑+)、NH(c1II→a1△)、NH2(A2A1→X2B1)的发射光谱,由相对光谱强度求得了形成各产物的通道比;分析NH(A3II,v＇=0)的转动分辨谱的结果表明,v＇=0能级上的转动布居是"双模”分布,激发态产物NH(A)、NH2(A)的形成机理可能是: He(23S)+N2H4→N2H4*→NH(A)+NH2(A)+H.
关键词:
碰撞传能
,
化学发光
,
NH(A3Ⅱ)的发射光谱
刘长友
,
谷智
,
王涛
,
查钢强
,
介万奇
功能材料
研究了低浓度（0.01～0.20mol/L）N2H4.H2O条件下ZnO微晶的低温水热结晶特性。N2H4.H2O弱碱性和N2H5＋吸附配位性影响ZnO微晶的形核和各晶面的生长速率。随着N2H4.H2O浓度的提高,ZnO微晶分别呈板条状、六角片状和六角棒束状。碱性分散剂和超声的分散作用影响主要在成核阶段;受分散剂弱碱性的影响,0.20mol/L N2H4.H2O显现出强的还原性,N2气泡模板生长机制使所制ZnO微晶呈六角管状晶须束。
关键词:
氧化锌
,
水热合成
,
结晶习性
,
水合肼
程平
,
王鸿梅
,
李建权
,
张为俊
,
曹德兆
,
储焰南
量子电子学报
doi:10.3969/j.issn.1007-5461.2003.03.006
利用微波放电电离质谱装置,分别通过N2与O2、水蒸气与空气的微波放电,产生了大气中存在的NO+和H3O+.(H2O)n离子,动力学过程的分析和讨论表明这几种离子是由大气中的初始反应离子N+2、N+、O+2、O+与周围环境中的原子、分子经过一系列的离子-分子反应产生的.这一结论也同时模拟了大气中NO+和H3O+.(H2O)n的形成过程.
关键词:
微波放电
,
大气
,
离子化学
