Zeolite NaY-mediated oxidation of dyes with H2O2: unique heterogeneous non-transition metal center cleavage of H2O2 under visible light irradiation

This study investigated the visible-light catalysis mediated by zeolite NaY on the oxidation of dyes with H₂O₂. The results demonstrated that zeolite NaY acts as a sink for the electron from the photo-excited dye in the heterogeneous catalysis. Furthermore, the electron can effectively activate H₂O₂ to produce ^·OH radical that is a powerful oxidant for the oxidation of dye at room temperature. The effects of the framework topology, Si/Al ratio, and exchangeable cation of the zeolite on the oxidation of various dyes were also shown.     

Zeolite NaY-mediated oxidation of dyes with H2O2: unique heterogeneous non-transition metal center cleavage of H2O2 under visible light irradiation

This study investigated the visible-light catalysis mediated by zeolite NaY on the oxidation of dyes with H2O2. The results demonstrated that zeolite NaY acts as a sink for the electron from the photo-excited dye in the heterogeneous catalysis. Furthermore, the electron can effectively activate H2O2 to produce ·OH radical that is a powerful oxidant for the oxidation of dye at room temperature. The effects of the framework topology, Si/Al ratio, and exchangeable cation of the zeolite on the oxidation of various dyes were also shown.     

聚硫堇/过氧化氢光致电化学敏感界面的构建及其对葡萄糖氧化酶催化活性的测定

将具有光电活性的硫堇电聚合在光透电极的表面,制备了聚硫堇膜光电极,利用该电极同时具有光敏和电子受体的性能,使其与葡萄糖氧化酶对葡萄糖催化反应产生的电子供体(过氧化氢)发生光致电化学反应,通过检测由此产生的光电流实现对蛋白质催化活性的检测.本文探讨了聚硫堇/过氧化氢光致电化学敏感界面的响应机理,讨论了偏压、电解质溶液pH和底物浓度对光致电化学反应和测定葡萄糖氧化酶催化活性的影响.通过测定商品葡萄糖氧化酶的催化活性,验证了方法的可行性.应用该敏感界面检测蛋白质的催化活性不需要过氧化物酶,比光度法经济、简便和快速.     

H2O/NaY吸附体系的热化学研究

用精密自动绝热量热计测定了在220-320K范围内, 不同含水量的H2O/NaY吸附体系的热容. 结果表明, 在这些吸附体系的Cp-T曲线上均没有水的固-液相变峰. 这说明即使在饱和吸附的情况下, 水分子仍以单分子层的形态存在于NaY表面上, 它们没有形成聚集态. 此外, 还测定了往饱和吸附的H2O/NaY中再加入不同量水后所组成的H2O/NaY体系的热容. 在这些Cp-T曲线上都出现了明显的相变峰. 所加之水一旦脱出, 则相变峰又消失. 这些水存在于分子筛颗粒之间只与外表面接触. 但仍受分子筛表面的影响. 所以它们的熔化热、熔化温度均比正常水的     

A highly selective photooxidation approach using O2 in water catalyzed by iron(II) bipyridine complex supported on NaY zeolite

A new photocatalytic system involving iron(II) bipyridine supported on NaY zeolite (FeBY) shows excellent reactivity and selectivity in the oxidation of organic compounds. This approach allows highly controlled oxidation reaction to occur but avoids undesirable mineralization into CO2 and H2O.     

NiCo_2O_4对H_2O_2在碱性溶液中电化学还原反应的催化行为(英文)

利用溶胶-凝胶法合成纳米NiCo2O4,并利用X射线衍射和透射电镜分析其结构和表面形貌.结果表明NiCo2O4具有尖晶石结构,平均粒径约为15 nm.利用电势线性扫描和恒电势法测定了其对H2O2在碱性溶液中电化学还原反应的催化性能.发现NiCo2O4对H2O2电化学还原具有高的催化活性和稳定性,在H2O2浓度低于0.6 mol.L-1时,其电化学还原反应主要通过直接还原途径进行.以NiCo2O4为阴极催化剂的Al-H2O2半燃料电池在室温下的开路电压达1.6 V;在1.0 mol.L-1 H2O2溶液中,峰值功率密度达209 mW.cm-2,此时电流密度为220mA.cm-2.     

TS-1/H2O2体系催化二乙胺氧化竞争反应

系统研究了TS-1/H2O2催化二乙胺(DEA)氧化制备二乙基羟胺(DEHA)的反应规律,考察了DEA氧化及DEHA氧化反应之间的竞争关系.结果表明,H2O2以连续方式进料时,DEA转化率及H2O2有效利用率明显提高,而反应体系中DEA/H2O2的摩尔比对DEHA选择性的影响较大.TS-1既可催化DEA的氧化,又可催化...     

微过氧化物酶-11修饰电极对O2和H2O2的电催化还原

运用电化学循环伏安法和旋转圆盘电极技术研究了Ｏ２和Ｈ２Ｏ２在Ｎａｆｉｏｎ膜固定的微过氧化物酶－１１修饰的玻磷（ＭＰ－１１＋Ｍａｆｉｏｎ／Ｇｃ）电极上的电化学还原,结果表明,饰电极 对Ｏ２和Ｈ２Ｏ２的还原均具电催化作用。测定和比较了Ｏ２和Ｈ２Ｏ２在ＭＰ－１１＋Ｎａｆｉｏｎ／ＧＣ的电极上电催化还原反应的一些动力学参数。发现Ｏ２在修饰电极上经历了四电子还原,且还原过程与溶液的ＰＨ值有关。     

Oxidation of H2 and CO over ion-exchanged X and Y zeolites

Zeolites X and Y exchanged with Group IA cations were synthesized by aqueous ion exchange of NaX and NaY and used as catalysts in the oxidation of H2 and CO at temperatures ranging from 473 to 573 K. The CsX zeolite was the most active material of the series for both reactions whereas HX was the least active. Moreover, the oxidation of CO in H2 was very selective (approximately 80%) over the alkali-metal exchanged materials. Isotopic transient analysis of CO oxidation during steady-state reaction at 573 K was used to evaluate the coverage of reactive carbon-containing intermediates that lead to product as well as the pseudo-first-order rate constant of the reaction. A factor of 4 enhancement in activity achieved by exchanging Cs for Na was attributed to a higher coverage of reactive intermediates in CsX because the pseudo-first-order rate constant was nearly same for the two materials (approximately 0.7 s(-1)). The number of reactive intermediates on both materials was orders of magnitude below the number of alkali metal cations in the zeolites but was similar to the number of impurity Fe atoms in the samples. Because the trend in Fe impurity loading was the same as that for oxidation activity, a role of transition metal impurities in zeolite oxidation catalysis is suggested.     

Intercalation of xylenol orange, morin and calmagite into NaY zeolite and their application in dye/zeolite modified electrode

The intercalation of xylenol orange, morin and Calmaigite into NiaY zeolite were studied by XRD, TGA, and BET and diffuse reflectance. These dye incorporated into NaY zeolite by ion exchange in aqueous phase. Results show that xylenol orange can be intercalating better into zeolite. The dye molecules are strongly retained in the channels of zeolites. The prepared intercalated dye/zeolite, for the first time, was used as the modifier for carbon past electrode. The dye/zeolite modified carbon paste electrode was developed for the voltammetric determination of Cu(II). Copper(II) was selectively preconcentrated. Results shows the peak current intensity increased in order of calmagite > xylenol orange > morin dyes intercalated in zeolite. The results agree with complex formation of those dyes as chelating agents with Copper(II).     

Ti－Si沸石表面吸附物种的TPSR－TPD研究

氯丙烯在不同催化剂表面上吸附的ＴＰＤ结果表明：在ＴＳ－１上有三重脱附峰，而在ＴｉＯ２／Ｓｉｌｉｃａｌｉｔｅ上仅有单峰。Ｈ_２Ｏ_２或分子Ｏ_２在催化剂表面吸附后，在脱附物种中可用质谱检测到原子Ｏ（１６）物种；说明Ｈ_Ｏ_２或分子Ｏ_２在样品表面存在解离吸附；并发现解离分子Ｏ_２的活性很低。ＴＳ－１能同时吸附氯丙烯和Ｈ_２Ｏ_２，而在ＳｉＯ_２／Ｓｉｌｉｃａｌｉｔｅ表面的吸附却与吸附顺序有关。环氧化活性顺序如下：ＴＳ－１（ＴＰＡＯＨ）＞ＴＳ－１（ＴＰＡＢｒ＋ＮａＯＨ）＞ＴｉＯ_２／Ｓｉｌｉｃａｌｉｔｅ。ＴＳ－１沸石的高氧化活性可能与Ｈ_２Ｏ_２吸附后表面原子Ｏ（１６）的形成有关。     

TiO2/NaY Composite as Photocatalyst for Degradation of Omethoate

Photocatalytic activities of TiO2 and NaY zeolites-supported TiO2 were investigated with omethoate as a model pollutant.The physical and chemical states of NaY zeolite-supported TiO2 were evaluated via XRD,FTIR,BET and SEM.Photodegradation of omethoate was studied with H2O2 as oxidant and TiO2 supported on NaY zeolite as photocatalyst.Parameters involved in the photo-catalysis of omethoate,i.e.,the calcination temperature of the photocatalyst,initial omethoate concentration,the amount of TiO2 loaded on NaY ...     

Fe2O3改性NaY沸石上吡咯烷亚硝胺的降解

 采用程序升温表面反应（TPSR），NH3－TPD，TG－MS和脉冲催化反应等手段研究了吡咯烷亚硝胺（NPYR）在Fe2O3改性NaY沸石上的催化降解．结果表明，用微波辐射、浸渍或焙烧等不同方法制备的改性沸石对NPYR降解的催化性能各不相同，以浸渍法制备的样品活性最高，但该样品对降解产物NO2的吸附作用较弱．在NPYR的降解反应中，Fe2O3改性NaY沸石上的Fe向沸石外表面迁移和富集，覆盖了沸石表面的铝，使催化剂表现出Fe2O3的性质．     

嵌入Y型沸石中Pd簇的合成及其催化性能

以［Ｐｄ（ＮＨ３）４］（ＮＯ３）２·Ｈ２Ｏ作为离子交换前驱物，应用微波交换－氢还原法合成了嵌入Ｙ型沸石中的Ｐｄ簇合物。ＸＲＤ和ＰＸＳ测试结果表明，在合成过程中，焙烧阶段的温度是影响Ｐｄ原子进入沸石体相形成Ｐｄ簇的主要因素。在焙烧温度２４０℃和还原温度２１０℃的制备条件下，Ｐｄ含量高达６．１３％（质量分数）也能进入Ｙ型沸石体相形成Ｐｄ簇。在相同条件下制得Ｐｄ含量仅为０．４１０％（质量分数）的样品，在     

硫化合物与H2O2在非催化反应中的非线性行为

硫化学反应中的非线性是近年来非线性化学研究的热点之一，我们注意到CU（11催化剂存在时H202氧化KSCN山、N。。S。0开］出现振荡或复杂振荡现象，但这两个反应的机理研究尚处在不成熟或模糊阶段＊‘1，由于K盯N、＊。。a0。和优（＊H小氧化过程有多种价态的变化，Cu（11）催化     

硫酸溶液中Ag+离子对Mn2+离子阳极氧化的催化作用

Anodic oxidation of Mn2+ and Ag+ ions and anodic oxidation of Mn2+ ion on platinum electrode in H2SO4 solution catalyzed by Ag+ ion are studied by using RRDE and triangle voltammetry techniques. Mn2+ ion is oxidized on the anode surface with adsorped OH group to form a certain compound containing Mn3+, which causes Mn2+difficult to be oxidized directly on anode. Near the potential of oxygen evolution from H2O decomposition, Ag+ ion is oxidized to form Ag2+ ion. This is the main reaction on anode because of its reversability. At higher potential silver oxide is formed on the anode. The oxide catalyzes the decomposition of H2O strongly. The anodic oxidation of Mn2+ion catalyzed by Ag+ takes place and Ag2+ ion and silver oxide are no longer the product of Ag+ anodic oxidation when Mn2+ exists in solution at the potential for Ag+ anodic oxidation. It is confirmed that the catalysis reaction is homogeneous and very fast.     

利用Taguchi法以高岭土为原料制备高硅NaY分子筛

采用Taguchi试验方法优化出了以高岭土为原料制备高硅NaY分子筛的最佳合成参数,考察了硅溶胶的加入量、反应体系的碱度、加水量以及晶化时间对NaY分子筛硅铝比和结晶度的影响。结果表明,高硅NaY分子筛的最佳合成条件是：反应体系各组分的物质的量比为7.5SiO₂∶1.0Al₂O₃∶2.2Na₂O∶120H₂O,晶化时间为16 h。同时发现,对合成样品性能的影响最为显著的因素是硅溶胶的加入量和碱度。采用X射线衍射、N₂静态容量吸附法和扫描电镜对利用最佳条件所合成样品的硅铝比、比表面积、孔分布以及表观形貌进行了表征。结果显示,以高岭土原料制备的NaY分子筛比参考样品拥有更高的硅铝比和更大的比表面积。     

Decomposition of N2O on Rh-loaded zeolites

N₂O was decomposed over Rh supported on NaY zeolite and ZSM5. With low Rh-loading (≤0.1 wt.%) the activity of Rh was much higher than that supported on SiO₂ and CeO₂. On the contrary, the activity of Rh-loaded zeolites (0.1 wt.%) was not so high or even lower than that on SiO₂ for the oxidation of toluene, which has a larger molecular size than N₂O. Thus the Rh present inside the zeolite cavity was especially effective in the decomposition of N₂O.     

基于聚硫堇/过氧化氢光电化学敏感界面的胆碱传感器

将胆碱氧化酶固定在具有光电活性的聚硫堇光透电极的表面,利用壳聚糖和戊二醛键合胆碱氧化酶制备了光致电化学胆碱传感器.此传感器基于同时具有光敏和电子受体功能的聚硫堇光电界面,能与胆碱氧化酶催化胆碱反应产生的电子供体(H2O2)发生光致电化学反应的原理,实现了对胆碱的检测.探讨了传感器的光致电化学响应机理、偏压、光强及电解质...