丙烯选择氧化铋钼铁复氧化物催化剂组成,结构及性能的研究

采用XRD、Raman、XPS及催化剂性能评价等手段,考察了Bi_3(FeO_4)(MoO_4)_2和Fe_2(MoO_4)_3分别存在及两者共存时对Bi-Mo复氧化物体系催化性能的影响.结果表明,这两种含Fe物种的存在都有助于改善Bi-Mo系复氧化物催化剂对丙烯选择氧化反应的催化性能.但两者在作用机理上有所不同.Fe_2(MoO_4)_3本身无催化活性,但在反应条件下可部分还原为FeMoO_4形成Fe~(3+)/Fe~(2+)氧化还原对;且其地结构上与α-Bi_2(MoO_4)_3相匹配,这些因素都有助于促进催化体系中电子和氧物种的传递及催化剂表面活性中心的再生,从而提高催化性能.Bi_3(FeO_4)(MoO_4)_2在反应条件下也可形成Fe~(3+)/Fe~(2+)氧化还原对,但由于其Fe~(3-)所处的化学环境与Fe_2(MoO_4)_3很不相同,且Fe的含量也不及Fe_2(MoO_4)_3,因此它在促进催化体系中电子和氧物种的传递及催化剂表面活性中心的再生等方面的性能较差,但它对提高催化剂表面的活性中心(Bi-Mo对)数目有贡献.     

水解聚合铝溶液中Al30形态的研究

水解聚合铝形态一直是分析、催化、土壤、地球化学、新材料、环境科学和生物毒理学等众多领域研究的前沿和热点。Keggin 结构的Al₃₀ 形态是迄今为止发现的电荷最高的水解铝聚合阳离子,具有独特的分子结构和纳米分子尺寸,它对催化化学、新型功能材料、高效絮凝剂的开发以及铝的水解聚合转化规律研究具有重要意义。本文主要论述了Al₃₀形态的形成、形态分析方法、结构模型以及形成机理等方面的最新研究进展,并对水解聚合铝溶液的研究发展趋势进行了展望。     

烯烃氢甲酰化催化剂活性物种的原位~1H NMR研究

有机磷配位铐或钴联基配合物是生产难或醇的工业催化剂，一般公认金属氢化物是反应的催化活性物种．通常反应活性物种仅存在干反应状态下，其结构表征非常困难，在许多研究中只能关联催化剂母体与其活性的关系［‘1；而未能揭示出催化的本质，给催化剂设计造成很大困难，因而对催化剂活性物种的直接表征受到普遍关注．B。wn问、Morrista］及本文作者研究组＊均采用加压原位红外光谱方法，在烯烃氢甲酸化反应条件下捕捉到HCO（CO）3L存在的信息·但用相同方法在反应条件下，在RhH键特征吸收谱带195O－2200Cm‘内未观测到错氢化物的Rh－…     

Determination of molecular orientation distribution of a stable paramagnetic probe in oriented 4-cyano-4’-<Emphasis Type="Italic">n</Emphasis>-pentylbiphenyl

The molecular orientation distribution function of a stable radical 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl in magnetic-field oriented 4-cyano-4’-n-pentylbiphenyl was determined from the angular dependence of the ESR spectra. The preferred molecular orientation of radical species in the liquid crystal matrix was determined. The temperature evolution of the orientation distribution function was studied.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 190–195, January, 2005.     

V-Ag-Ni系氧化物的表面氧性质与甲苯选择性氧化的催化性能

制备了一系列Ｖ，Ａｇ，Ｎｉ原子比不同的三元氧化物，应用ＴＰＤ－ＭＳ技术研究了样品表面氧的性质，并测定了甲苯选择性氧化生成苯甲醛的催化活性。实验结果表明，样品表面存在有多种吸附的氧物种。在脱附温度＜９００℃：当Ｎｉ含量对Ａｇ（或Ｖ）的原子比为０．２５或０．５０时，仅在低温处出现有表面的Ｏ＾－和Ｏ＾２＾－两种氧物种的脱附峰；当Ｎｉ含量对Ａｇ（或Ｖ）的原子比增高到＞０．７５时，除有表面的Ｏ＾－和Ｏ＾２＾     

Trace elemental determination in alcohol automotive fuel by electrothermal atomic absorption spectrometry

Suitable analytical methodologies were developed allowing direct determination of As, Cu, Fe, Pb, Sb and Sn in alcohol fuel samples by electrothermal atomic absorption spectrometry. Different chemical modification approaches were tested and compared in terms of analytical performance and in practical terms. Experimental conditions were optimized allowing little sample dilution and use of calibration curves prepared with aqueous inorganic analyte standards. Methodologies were tested with analyte spiked alcohol samples. Good analyte recoveries from spiked alcohol samples, precision better than 10% and limits of detection in the sub μg l⁻¹ range were achieved.     

Biological Activity of Flavonoids Copper Complexes

Three flavonoid copper(II) complexes Cu₂(quercetin)(CH₃COO)₃(CH₃OH) ( 1 ), Cu(anthrarufin)(CH₃COO)·1/2H₂O ( 2 ) and Cu(naringin)(OCH₃)(CH₃OH)₂ ( 3 ) have been synthesized and characterized by elemental analysis, IR, electronic absorption and EPR (X‐band) spectroscopy. The complexes have a strong protective action over the Δsod1 mutant of S. cerevisiae against reactive oxygen radicals generated by an external source of free radicals (H₂O₂ or the superoxide‐generating, menadione). On the other hand, the complexes cleave DNA efficiently even in the absence of reducing agents. The main reactive oxygen species responsible for the DNA strand cleavage have been determined using radical scavengers. A probably mechanism of the DNA damage is proposed.     

Selective Oxidation of Methane to Methanol Using Molecular Oxygen on MoOx／（LaCoO3＋Co3O4） Catalysts

Comparatively high CH3OH selectivity (60.0%) and yield (6.7%) were obtained on MoOx/(LaCoO3 Co3O4) catalysts in selective oxidation of methane to methanol using molecular oxygen as oxidant. The interaction between MoOx and La-Co-oxide modified the molecular structure of molybdenum oxide and the ratio of O^-/O^2- on the catalyst surface, which controlled the catalytic performance of MoOx/(LaCoO3 Co3O4) catalysts.     

包覆Y(OH)3的球形Ni(OH)2的电化学性能

利用软嵌式粉末电极技术研究了Y(OH)3包覆对球形Ni(OH)2电化学性能的影响. 循环伏安结果表明, 在球形Ni(OH)2的氧化过程中存在Ni(Ⅲ)和Ni(Ⅳ)的两步氧化反应, 产生的Ni(Ⅳ)不稳定, 能分解产生NiOOH和氧气, 所以可将Ni(Ⅲ)→Ni(Ⅳ)看作副反应. Y(OH)3包覆层对Ni(OH)2氧化过程后期的副反应, 特别是Ni(Ⅲ)→Ni(Ⅳ)具有较好的抑制作用. 由包覆后的Ni(OH)2制成的模拟电池表现出很好的高温性能, 在1C充放电条件下, 当Y的摩尔分数为1.61%时, 在60 ℃时所对应的容量保持率可达到25 ℃的92.7％; 当Y的摩尔分数仅为0.55 %时, 在60 ℃时所对应的质量比容量也可达到241.3 mA·h/g.     

Inhibition of the toxic byproduct during photocatalytic NO oxidation via La doping in ZnO

It is of a great challenge to develop semiconductor photocatalysts with potential possibilities to simultaneously enhance photocatalytic efficiency and inhibit generation of toxic intermediates.In this study,we developed a facile method to induce the La doping and cationic vacancie(V(Zn))on ZnO for the highly efficient complete NO oxidation.The photocatalytic NO removal efficiency increases from 36.2%to 53,6%.Most importantly,a significant suppressed NO2 production also has been realized.According to the DFT calculations,ESR spectra and in situ FTIR spectra,the introduction of La^3+induce the redistribution of charge carriers in La-ZnO,which promote the production of·O2^- and lead to the formation of V(Zn)for the formation of·OH,contributing to the complete oxidation of NO to nitrate.Besides,the conversion pathway of photocatalytic NO oxidation has been elaborated,This work paves a new way to simultaneously realize the photocatalytic pollutants removal and the inhibition of toxic intermediates generation for efficient and safe air purification.