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

基于能量平衡的融雪过程模拟研究[C]

融雪过程是一种特殊的水文现象,其复杂的物理过程以及融雪过程的不确定性是模拟的重点和难点.本文基于对融雪性洪水预报的需求,针对融雪模拟过程中的重点和难点,在研究区多年融雪过程观测实验基础上,运用数值模拟方法,构建了基于能量平衡的单点双层融雪模型,对2010 年研究区点尺度的融雪期的能量项和融雪水量进行了模拟,模拟结果与实测结果较为符合

雪盖影响下季节性冻土消融期的土壤温度特征分析[C]

以天山北坡军塘河流域为研究区,采用定点对比连续观测的方法,利用2010 年3月至4 月1 日融雪期观测到的有雪盖和裸地两种不同下垫面的浅层(0cm,10cm,20cm,30cm,40cm)土壤温度气温资料,对比分析各层深度的土温变化情况、雪盖对其产生的影响及其与近地面气温之间的关系