以塑性材料为载体的新型钯/铑纳米催化剂

Chem．Commun报道了一种新型的负载于塑性材料上的钯和铑纳米催化剂，在超临界CO2体系中催化加氢反应。     

以塑性材料为载体的新型钯／铑纳米催化剂

Chem．Commun报道了一种新型的负载于塑性材料上的钯和铑纳米催化剂，在超临界CO2体系中催化加氢反应。     

钯、铂催化剂在硝基苯催化加氢合成对氨基苯酚反应中的比较

制备了一系列不同金属粒径的活性炭负载钯、铂催化剂,用于硝基苯液相催化加氢合成对氨基苯酚反应.采用N2-物理吸附、联碱滴定和TEM等表征手段对活性炭载体及其负载钯、铂催化剂进行表征.结果表明,对氨基苯酚选择性与钯、铂活性组分的金属粒径存在紧密的内在联系,说明活性炭负载钯、铂催化剂对于硝基苯液相催化加氢合成对氨基苯酚的反应...     

高分子负载钯催化Suzuki反应的研究进展

高分子负载钯催化剂与均相催化剂相比易于分离、可重复使用,同时大多数高分子负载钯催化剂保留了较高的催化活性。高分子负载钯催化剂已成为Suzuki反应催化剂的研究热点之一。本文综述了近年来高分子负载钯络合物及钯纳米催化剂在Suzuki反应中的研究进展。     

高活性负载型纳米金属加氢催化剂的制备

<正>产品和技术简介:本技术是一种负载型纳米金属加氢催化剂的制备方法,该方法可获得分散度高的负载型纳米金属催化剂。此类催化剂所用金属包括钯、钌、铂、铑及镍。该制备方法简单,成本低,重复性好,绿色无污染,催化剂寿命长,活性高,分别适用于硝基,芳环,炔烃,酮,醛等选择性加氢反应。     

载体的性质对CO气相催化偶联反应的影响

考察了以α－Al2O3为载体的负载型钯系双金属催化剂用于CO气相催化偶联制备草酸二乙酯反应的活性。研究了催化剂的比表面和孔结构对负载型钯系双金属催化剂的选择性和活性的影响。结果表明，催化剂的比表面对反应的选择性和活性的影响并不十分明显；孔结构则对其有较大的影响，其中孔容的影响较大，孔径也是有一定的影响；在合适的孔径范围内，CO转化率基本随孔容的减小而增大。     

贵金属纳米颗粒及其催化剂的生物还原制备技术

利用自行筛选的具有强还原能力的菌株制备得到银纳米颗粒,所得颗粒的粒径基本在10 nm以下,主要集中在2～8nm.将生物还原过程进一步引入催化剂制备过程.得到负载犁银催化剂和负载型钯催化剂,并将催化剂分别应用于1,2一丙二醇空气氧化合成丙酮醛、CO氧化生产CO2以及蒽醌加氢反应中.     

纳米K2CO3/CaO催化大豆油制备生物柴油

以K2CO3、纳米CaCO3(自制)为原料,K2CO3的负载质量分数为50%,在750℃焙烧3 h得到纳米K2CO3/CaO固体碱催化剂,并通过XRD、FT-IR及TG-DSC等手段进行确认.再用该催化剂催化制备生物柴油,结果表明:制备生物柴油的最佳条件为温度70℃,质量分数3%的纳米K2CO3/CaO,醇油摩尔比12...     

负载型Au／TiO2催化剂的研制及其性能研究

一氧化碳（CO）是涉及到工业、环保、军事和人类生活等多个方面的空气污染物,用于氧化CO的催化剂的研究是催化领域里的一个重要课题,目前用于氧化CO的催化剂主要是以铂、钯、铑等贵金属为主要活性组分和以氧化铜、氧化锰等一些过渡金属氧化物作为活性组分的催化剂。虽然这些催化剂已经商品化,但其在抗湿、抗硫中毒等诸多性能方面仍存在一些缺陷。因而有必要研制和开发用于CO净化的高效催化剂。目前的研究表明,沉积沉淀法是制备负载型催化剂最好的方法。金（Au）作为活性组分具有较好的催化效果,且其价格相对于铂、钯等贵金属较为低廉．从一定程度上降低了原材料的成本;而以具有多相光催化性能的半导体二氧化钛（TiO2）为载体,将会兼具二者的优势,与活性组分产生协同效应。可是,目前关于Au／TiO2催化剂在抗水／抗硫性能等方面的研究尚有欠缺。 为此,本实验以TiO2为载体,分别采用沉积沉淀法和改良浸渍法制备一系列Au／TiO2催化剂,探索高性能Au／TiO2催化剂的制备技术,同时考察该类催化剂在不同条件下对CO的催化氧化效果及其抗湿、抗硫性能。     

金-钯/二氧化锆催化剂合成及其光催化性能研究

采用硼氢化钠还原法制备了二氧化锆负载金-钯双金属催化剂,利用X射线衍射(XRD)、透射电子显微镜(TEM)、紫外-可见漫反射(UV-vis DRS)等手段对催化剂进行表征。结果显示,金、钯成功负载于二氧化锆上,且金、钯以球形颗粒均匀分散,粒径为4~7 nm,形成了双金属纳米催化剂。金-钯双金属纳米催化剂具有强吸收光能力,在35℃±3℃、可见光照射条件下用于催化Ullmann偶联反应具有很好的催化活性。催化剂中金、钯比例影响催化活性,金与钯的质量比为2∶1时催化剂对Ullmann偶联反应活性最佳。     

典型煤炭燃料在民用解耦炉中的燃烧实验研究

实验对比研究了烟煤块状半焦及烟煤型煤等煤炭燃料在民用解耦炉中燃烧时的污染物排放特性和炊事能力，并基于解耦测试炉对烟煤型煤的特征尺寸进行优化，验证了解耦炉具对不同种类民用煤炭燃料的适应性。结果表明，民用解耦燃煤炉具特有的结构特征和通风方式有利于NOx和CO的同时减排。若在解耦炉中燃烧烟煤洁净型煤，可进一步实现对SO2和颗粒物(PM)的有效控制。型煤尺寸对炉具污染物排放影响显著，尺寸优化后的烟煤洁净型煤在解耦炉中稳定燃烧时NO, SO2, CO和PM的平均排放浓度按基准氧含量9vol%折算后，分别低于190, 300, 380和30 mg/m3，炊事功率可达1.65 kW。     

民用解耦燃煤炉中的NO x 和CO同时减排

典型民用解耦燃煤炉具有底部连通的两个分别被称为热解室和燃烧室的并列炉膛，煤炭从热解室上部加入，空气通过热解室底部的倾斜炉排引入。结合煤炭燃烧过程中的氮转移路线与解耦炉中的气体循环流动特征，定性分析了民用解耦燃煤炉中的NO _x 和CO同时减排机理，并在此基础上对配风和煤种等因素对NO和CO排放的影响进行了定量实验研究。结果表明，民用解耦燃煤炉特有的结构特征和通风方式有利于NO _x 和CO的同时减排，解耦炉具与洁净型煤匹配可显著降低综合污染物排放。     

Catalytic purification of flue gas from civil-used stove

Effects of the method of burning and addition of catalysts in the chimney of civil-used stove on emission of air pollutants were studied. Alumina-supported copper and manganese oxides and palladium catalysts were used to purify the flue gas emitted from the civil-used stoves. The results show that, in upper burning case, both Cu–Mn–O/Al₂O₃ and Pd/CuO/Al₂O₃ catalysts can decrease the ratio of CO/CO₂ to <0.01, and remove SO₂ and volatile organic chemicals (VOC) from the flue gas to some extent. Deactivation of the catalyst results from the accumulation of sulfate groups on catalyst support. The life of the catalyst can be extended by adding a honeycomb of lime before the catalyst.     

煤燃烧时CO2排放因子的研究

对CO2排放量进行可靠预测可为燃煤发电机组CO2排放量和减排量的计算提供基础。针对中国动力用煤,分别对以空气干燥基和干燥无灰基为基准的煤质特性参数进行CO2排放因子预测公式的拟合,并利用另一个数据库对已拟合的预测方程进行检验。     

Oxidation of benzene to phenol on supported Pt-VOx and Pd-VOx catalysts

Gas-phase oxidation of benzene using a mixture of oxygen and hydrogen has been carried out on silica-supported vanadium oxide catalysts modified with platinum or palladium. Catalyst activity and phenol selectivity were studied as a function of the precious metal used, the vanadium oxide loading as well as of temperature. The binary catalysts have been characterized by TPR and TEM. Pt-VO_x/SiO₂ catalysts were more active than Pd-VO_x/SiO₂ catalysts. By using platinum catalysts benzene conversion amounted to 1.0% (S_phenol=97%) at 413 K, whereas palladium catalysts reached a conversion of only 0.2% (S_phenol=86%) for the same contact time and temperature. The most active catalyst for the oxidation of benzene to phenol was a low vanadium loaded 0.5 wt.% Pt–3 wt.% V on silica catalyst. At temperatures above 413 K phenol selectivity decreased strongly because of enhanced total oxidation. Active catalysts need both components: a dispersed transition metal oxide such as VO_x as well as small precious metal particles such as platinum. The activity of the catalysts arises from a close interaction between the redox-active compound VO_x and the electron mediator and hydrogen activator platinum as was confirmed by correlation of catalytic results and catalyst properties. Highly dispersed platinum particles are exclusively located on the vanadium oxide covered surface as demonstrated by TEM investigations. TPR studies showed and enhanced reducibility of a part of vanadium(V) oxide indication a close neighborhood of VO_x and platinum.     

Performance of Ni/Nano-ZrO2catalysts for CO preferential methanation简

Large surface areas nano-scale zirconia was prepared by the self-assembly route and was employed as support in nickel catalysts for the CO selective methanation. The effects of Ni loading and the catalyst calcination temperature on the performance of the catalyst for CO selective methanation reaction were investigated. The cata- lysts were characterized by Brunauer-Emmett-Teller （BET）, transmission electron microscope （TEM）, X-ray dif- fraction （XRD） and temperature-programmed reduction （TPR）. The results showed that the as-synthesized Ni/nano-ZrO2 catalysts presented high activity for CO methanation due to the interaction between Ni active particle and nano zir- conia support. The selectivity for the CO methanation influenced significantly by the particle size of the active Ni species. The exorbitant calcination resulted in the conglomeration of dispersive Ni particles and led to the decrease of CO methanation selectivity. Among the catalysts studied, the 7.5% （by mass） Ni/ZrO2 catalyst calcinated at 500℃ was the most effective for the CO selective methanation. It can preferentially catalyze the CO methanation with a higher 99% conversion in the CO/CO2 competitive methanation system over the temperature range of 260-280℃, while keeping the CO2 conversion relatively low.     

略论大同城市燃煤SO2排放的控制

对大同市燃煤设施电厂锅炉、工业炉窑及民用燃煤的 SO2 污染情况进行了分析 ,探讨了减少SO2 的排放应采取的相应技术对策     

煤炭循环经济对CO2减排的研究

基于碳循环分析,提出煤炭转化为高热值燃料的必要性,煤矿循环经济建设将为CO2减排提供多重选择;通过分析潞安集团在煤炭绿色开采、煤炭清洁高效利用、矿区生态建设方面取得的成绩,说明循环经济减排CO2的有效性;大型煤炭企业实现碳材料资源的深层次循环将为CO2减排及低碳经济模式建立做出突出贡献。     

脱矿物质对铁镍催化煤焦—CO2气化反应性的影响

在先锋褐煤的原煤、脱矿物质煤中掺加一定量的金属Fe、Ni、Ca的硝酸盐,在固定床管式碳化炉上,600℃制焦。XRD技术测试了煤焦中金属元素的存在形态,程序升温法测定了上述煤焦的CO_2气化反应活性。结果表明,Si对Fe催化煤焦—CO_2气化反应没有影响,而Ca对Fe、Ni的催化行为有促进作用,原因在于Ca元素有助于Fe物种的还原和Ni物种在煤焦表面的分散,而Si元素以SiO_2的形式分散在煤焦中,未与Fe形成不溶体,因而不影响Fe的催化作用。     

Efficiency of catalytic processes for the reduction of CO and VOC emissions from wood combustion in domestic fireplaces

Pollutant characterization of domestic fireplaces, according to two paces of functioning (normal and low-charge phase) was performed. Two catalysts supported on cordierite or metal were placed in the exhaust of two domestic fireplaces (old and new generation) in order to reduce gaseous pollutants. Active phase of catalysts is composed of noble metals (Pd, Pt) and cerium. Methane was the dominant compound of the released Volatile Organic Compounds (VOC, 80% b. v.). Products resulting from incomplete combustion (CO and other VOC) did not represent more than 6% of the initial carbon content in wood. Lower concentration of CO in the exhaust was obtained with the new generation fireplace as compared to the older one with mean concentrations of CO normalized for 13% oxygen b.v. equal to 0.12% and 0.3%, respectively. Emission of VOC is also drastically reduced for new generation fireplace. The presence of a catalyst induced a decrease of the CO and VOC emission factors during ignition and low-charge phases by factors ranging from 65% to 70%. The abatement of VOC for the old generation fireplace was better in the presence of metal as compared to cordierite, with efficiency values of 65% and 30%, respectively. The new fireplace was the one on which the addition of the cleanup implements had most impact. Besides the introduction of a catalyst, a heating system of the fume was set up below the catalyst. This heating system allowed a faster activation of the catalyst, particularly during ignition and low-charge phases. Best abatements were obtained with the heated metallic support with values close to 80% and 94% for VOC and CO respectively.