Transition Metal Promoted ZSM-5 Catalysts for the Conversion of Dimethyl Sulfide into Methanethiol

负载过渡金属的zSM-5催化剂用于催化甲硫醚(dMS)转化成甲硫醇(MT)的反应.实验结果表明,催化剂的甲硫醚转化率提高和甲硫醇选择性降低的趋势一样,都是以下顺序:CO/zSM-5>MO/zSM-5>nI/zSM-5>W/zSM-5.表征结果表明,由于过渡金属阳离子(W6+、nI2+、CO3+、MO6+)比Al3+活泼,而改性过程中W6+、nI2+、CO3+、MO6+分别代替了部分Al3+,使得改性催化剂对dMS和MT的化学吸附作用更强.过渡金属的引入使得zSM-5总酸度增强,提高了C―S键的裂解能力,从而改进了催化转化dMS的能力.研究结果发现,在转化dMS的过程中,金属活性位和酸性位之间通过强的协同效应起作用.ZSM-5-supported transition metal catalysts were prepared and used to catalyze the conversion of dimethyl sulfide(DMS) into methanethiol(MT).Test results indicated that the activities of the catalysts for the conversion of DMS increased as follows: Co/ZSM-5>Mo/ZSM-5>Ni/ZSM-5>W/ZSM-5.The decrease in MT selectivity followed the same trend.The characterization results showed that transition metal cations(W6 +, Ni2 +, Co3 +, Mo6 +) replaced some Al3 +sites leading to more active in chemiadsorption of DMS and MT since transition metal cations are more active than Al3 +.The incorporation of transition metals into ZSM-5enhances the total acidity of ZSM-5 and increases its capacity to rupture C―S bonds.This subsequently improves its catalytic behavior in the conversion of DMS.We found that the metal active sites and closely situated acidic sites have a strong synergistic effect when converting DMS

镍促进CuO-CeO_2催化剂的结构表征及低温CO氧化活性(英文)

制备了一系列CO低温氧化的Ce20Cu5NiyOx催化剂,并采用氮气低温物理吸附、X射线衍射、程序升温还原、X射线光电子能谱以及拉曼光谱等手段对催化剂进行表征.结果表明,Ce20Cu5Ni0.4Ox催化剂活性最高.NiO的添加可以使得较多的Cu物种掺杂到CeO2晶格中,通过形成铈镍固溶体产生更多的氧空位.表征结果显示,Ce20Cu5Ni0.4Ox催化剂中存在大量的Cu+,Ce3+及晶格氧,催化剂中的Cu+很容易进入到氧化铈晶格,形成Cu-O-Ce固溶体,从而增强了在还原气氛下晶格氧的释放能力.Ce20Cu5Ni0.4Ox催化剂高的催化活性主要归因于大量Cu+以及形成的Cu-O-Ce和Ni-O-Ce固溶体

Promotion of Magnesium Oxide on Catalyst for Ethylbenzene Dehydrogenation to Styrene

制备了一系列不同Mg含量的fE-k-CE-Mg乙苯脱氢催化剂,并以Xrd、CO2-TPd、nH3-TPd和bET等方法对催化剂进行表征,考察MgO对乙苯脱氢催化剂表面结构、酸碱性以及催化性能的影响.结果表明,添加适量的MgO可以增大催化剂的孔径和孔容,降低比表面积,形成的MgfE2O4新相有助于分散催化剂表面的活性相kfEO2和kfE11O17,并增加催化剂表面CEO2的含量,同时也调节催化剂表面的酸碱度,降低催化剂表观活化能,在水油体积比1.3且空速为1H-1时,MgO的质量分数为6%的催化剂活性最高.A series of Fe-K-Ce-Mg based catalysts for ethylbenzene(EB) dehydrogenation to styrene were prepared and characterized by means of X-ray diffraction(XRD),temperature-program desorption(CO2-TPD,NH3-TPD),BET techniques.The effect of the content of magnesium oxide added on the performance of the catalysts for the reaction was investigated.The catalyst activity of the MG-6 catalyst containing 6% magnesium oxide was found to be best for the reaction under the conditions of water-oil volume ratio about 1.3 and space velocity 1 h-1.The characterization results showed that the pore size and pore volume of the catalyst increased as increasing the content of magnesium oxide,while,the surface area decreased by adding magnesium oxide;new phase MgFe2O4 promoted the formation of KFeO2 and KFe11O17 and increased the content of CeO2 on the catalyst surface,adding magnesium oxide also adjusted the acidity-alkalinity of catalyst surface and decreased the apparent activation energy values,which was found to be responsible for the improvement of the catalyst

高通量作物表型监测:育种和精准农业发展的加速器

表型是研究"基因型-表型-环境"作用机制的重要桥梁,研发具有自主知识产权的作物表型监测平台对于加速育种进程和辅助精准农业监测具有重要意义。Crop 3D表型监测系统以水稻和玉米等主要粮食作物为研究对象,实现了多尺度、多时序作物全生育期的生长动态监测,为育种提供了重要数据支撑。文章首先综述了国内外关于表型平台的研究进展,进而介绍了Crop 3D系统平台的主要研究进展,最后对未来表型研究的方向进行了展望

2013年中国植物科学若干领域重要研究进展

2013年中国植物科学研究继续快速发展。中国科学家在植物科学多个领域中取得了大量的原创性、高水平研究成果,包括水稻(Oryza sativa)株型调控的激素信号转导机制、水稻育性的遗传调控机理、重要物种的基因组解析、植物天然免疫分子机制的结构生物学研究以及植物生态与环境生物学等。该文对2013年中国本土植物生命科学若干领域取得的重要研究进展进行了概括性评述,旨在全面追踪当前中国植物科学领域发展的最新前沿和热点事件,并展现我国科学家所取得的杰出成就

2004年中国植物科学若干领域研究进展

中文核心期刊要目总览(PKU)中国科学引文数据库(CSCD)004385-39