同时去除碳烟颗粒物和氮氧化物催化剂研究进展

针对柴油车尾气排放的两大主要污染物碳烟颗粒物和氮氧化物的同时催化去除,综述了贵金属催化剂、单一金属氧化物和复合金属氧化物催化剂的研究进展,并提出了该催化研究领域存在的主要问题及发展方向.     

金属氧化物催化剂在消除柴油车排气颗粒物中的应用

介绍了用于柴油车排气颗粒物后处理的金属氧化物催化剂，包括过渡金属氧化物、主族金属氧化物和碱土金属氧化物。较详细地讨论了催化剂组成及性能、相关催化反应、控制因素和反应机理。     

柴油机排放污染控制技术的研究进展

本文分析了柴油车排气污染物的组成、危害及目前所采用的一些主要的后处理技术。重点探讨了金属氧化物作为后处理技术中催化剂的发展概况,较详细的讨论了催化剂的组成及性能．相关的催化反应机理和控制因素。     

Ni、Pt对柴油车排气颗粒物去除催化剂的修饰作用

以改性整体式堇青石蜂窝陶瓷为载体,用Ni和Pt修饰Cu-K-V/TiO₂/γ-Al₂O₃ /cordierite催化剂,制备了用于消除柴油车排气颗粒物的催化剂;采用DSC/TG方法确定催化剂的活性及BET、TG-IR等方法对催化剂进行了表征,探讨了Ni和Pt对Cu-K-V/TiO₂/γ-Al₂O₃ /cordierite催化剂的修饰作用及老化对催化剂的影响.研究发现经Ni和Pt修饰后的催化剂能有效降低柴油车排气颗粒物的最大燃烧速率时的温度,特别是对颗粒物中最难燃烧的石墨化部分的去除;而且Ni和Pt的添加能提高颗粒物的去除效率.对含Pt催化剂,老化会降低催化剂的活性;而对含Ni的催化剂,老化使催化剂的活性增加,这可能是Ni向催化剂非孔道的外表面迁移的结果.     

催化氧化法去除甲醛最新研究进展

介绍了贵金属催化剂与过渡金属催化剂催化氧化去除甲醛的最新进展。详细讨论提高催化氧化法去除甲醛的方法,包括:常见载体负载贵金属、传统金属氧化物负载贵金属、特殊形貌负载贵金属以及过渡金属氧化物改性,并对催化氧化法去除甲醛提出展望。     

碳烟颗粒在NOx储存催化剂上的燃烧研究进展

柴油车排放的碳烟颗粒和NOx严重危害环境和健康,开发和应用柴油车排放后处理技术势在必行。总结了尾气后处理技术中碳烟颗粒在NOx储存催化剂上燃烧的技术发展路线以及研究进展,包括几种不同贵金属型和稀土混合氧化物型催化剂,同时归纳了其催化作用机理,并对NOx物种对碳烟燃烧活性影响进行归纳分析,对该技术在实际应用中存在的问题和应用前景进行了讨论。     

催化氧化法去除甲醛最新研究进展

介绍了贵金属催化剂与过渡金属催化剂催化氧化去除甲醛的最新进展。详细讨论提高催化氧化法去除甲醛的方法,包括:常见载体负载贵金属、传统金属氧化物负载贵金属、特殊形貌负载贵金属以及过渡金属氧化物改性,并对催化氧化法去除甲醛提出展望。     

选择性催化还原脱硝催化剂的研究进展

介绍了分子筛催化剂、金属氧化物催化剂以及碳基催化剂的优缺点,综述了各自的研究现状,并对选择性催化还原脱硝催化剂的发展前景进行了展望。     

柴油车尾气中烃类物质净化研究进展

随着全球机动车柴油化的发展,柴油车尾气有效可控排放提上日程。柴油车尾气中的碳氢化合物是柴油车在贫燃烧条件下工作时产生的未完全燃烧的碳氢物质。这些烃类物质对健康和环境有害,导致大气污染、臭氧形成和粉尘生成。本文介绍了通过油质改进、机内装置性能优化技术来减少尾气的排放,但这种技术成本昂贵、改善能力有限,所以必须与机外净化后处理技术相结合。现阶段柴油车尾气主流后处理装置有柴油车颗粒过滤器和氧化性催化转换器,它们虽一定程度上减缓了尾气的排放,但过滤筒易堵塞,柴油车排气温度更低,催化剂在温度低的环境下能力不足,因此引进了低温等离子体协同催化净化技术来处理柴油车尾气中的HC。     

直接甲醇燃料电池中碳基载体材料的研究进展

甲醇氧化电催化剂是决定直接甲醇燃料电池（direct methanol fuel cells, DMFCs）性能、寿命与成本的关键。为获得高功率密度和低生产成本的DMFCs,设计合成具有组成、结构、形貌可控的阳极催化剂备受关注。阳极催化剂的颗粒尺寸、粒径分布、形貌结构、稳定性、分散性以及催化活性都和负载它的载体息息相关,而碳基载体材料由于其优异的性能被广泛应用于DMFCs领域。本文分别介绍了酸性环境和碱性环境中甲醇氧化反应的机理,然后对不同形式的碳基载体材料,例如炭黑、介孔碳、碳纳米材料、氧功能化碳、杂原子掺杂碳、以及金属氧化物改性碳作为催化剂载体在DMFCs领域中的应用进行了综述,最后对DMFCs的发展趋势进行了展望。     

Preparation and Application of Perovskite Catalysts for Diesel Soot Emissions Control: An Overview

The diesel engines are energy efficient (1), but their particulate matter (soot) emissions are still a matter of concern even though major advances in their control are being made. For soot abatement, catalytic diesel particulate filter (DPF) technique is widely employed to trap and burn the soot. Many types of catalysts have been investigated for the soot combustion i.e. platinum group metal (PGM) based, perovskite-type oxides, spinel-type oxides, rare earth metal oxides, and mixed transient metal oxides etc. The cost of PGM catalysts is high and their availability is questionable. Further they are susceptible to poisoning and have low thermal stability. On the other hand perovskite catalysts show potential as effective soot oxidation catalyst for the DPF because of their low cost, high thermal stability and tailoring flexibility. Many papers related to soot oxidation over perovskite catalysts have been published but no review paper appears in the literature that is dedicated to soot oxidation. Thus, this article provides a summary of published information regarding pure and substituted perovskite catalyst, preparation methods, properties, and their application for diesel soot emission control.     

Catalytic behavior of potassium containing compounds for diesel soot combustion

Alkali doped oxides were synthesized and tested as catalysts for diesel soot combustion using a combinatorial method. It has been found that potassium shows better promotion of the catalytic activity than other alkali elements, and most of the potassium-rich oxides showed similar catalytic behaviors when catalysts and soot were mixed in a slurry. The influence of different mixing methods, including loose contact, tight contact and slurry (wet) mixing with different soot suspensions, on the catalytic behavior of some transition metal oxides, alkali metal carbonates and potassium-containing oxides were studied through thermogravimetry and XRD. The high activity of potassium-containing catalysts is found to be due to the intimate contact between soot and potassium cations caused by polar solvents. Potassium containing catalysts degraded after repeated thermal cycles due to the loss of potassium. It was also found that the addition of transition elements can inhibit the loss of potassium.     

大孔钙钛矿型氧化物催化剂制备及其对碳烟燃烧的催化性能

采用有机络合和溶液燃烧相结合的方法制备了La_1-xK_xFe_1-yCo_yO₃ (x=0, 0.1;y=0, 0.5)催化剂,通过X射线衍射（XRD）、傅立叶红外吸收光谱（FT-IR）和扫描电镜等分析手段对La_1-xK_xFe_1-yCo_yO₃ 催化剂进行了表征。结果表明,制备的催化剂为钙钛矿型复合氧化物,具有蜂窝状大孔结构,平均孔径大于50 nm。采用超声辅助的方法让碳烟颗粒扩散到催化剂孔道内,利用程序升温反应技术评价了La_1-xK_xFe_1-yCo_yO₃ 催化剂对柴油车尾气中碳烟颗粒物的催化燃烧活性,结果表明,大孔钙钛矿催化剂具有较高的碳烟催化燃烧活性,与纯碳烟的燃烧峰值温度(Tm）相比,下降了（165~239） ℃。通过A位和B位离子的部分取代,可以使钙钛矿型氧化物催化剂的催化氧化性能进一步提高,m降低超过70 ℃。     

Vm/MOx催化剂对柴油碳烟催化燃烧抗硫中毒性能的比较

用柠檬酸络合助溶的等体积浸渍法制备了不同载体(γ-Al2O3 、SiO2 、TiO2、ZrO2和CeO2)负载的系列钒氧化物催化剂,使用红外光谱对催化剂硫中毒老化后的结构进行表征,采用程序升温氧化反应技术评价了硫老化后的催化剂对柴油碳烟催化燃烧的活性.结果表明,负载钒基氧化物催化剂硫老化后,催化剂表面主要以亚硫酸盐物种...     

K- and Cs-FeV/Al2O3soot combustion catalysts for diesel exhaust treatment

Alkali-doped FeV oxide catalysts supported on -alumina were prepared and their catalytic activity in the combustion of diesel soot is reported. The catalysts were characterized by XRD, TPR and SEM–EDX analysis. The influence of the nature of the alkali metal (K and Cs), the temperature of treatment of the catalysts and the stability to sulfur poisoning have been investigated.

Catalysts doped with Cs were the most active and stable also after several combustion cycles and in the presence of sulfur in the stream. The activity measurements and microstructural results suggest that the combustion of soot is favored on catalysts where amorphous phases and/or mixed Fe---V---O phases, ensuring an intimate contact between iron and vanadium, are present. A reaction mechanism involving the participation of the redox couple Fe(II)–Fe(III) in the activation of the vanadium combustion sites, is proposed.     

同时消除柴油机尾气排放炭颗粒和NOx催化剂的研究进展

介绍了简单氧化物、复合氧化物(尖晶石和钙钛矿)催化剂都具有同时消除柴油机尾气中的炭颗粒和NO的活性．但是炭颗粒的起燃温度较高,生成N2的选择性差。在消除炭颗粒和氮氧化物时,有N2O生成,造成二次污染,炭颗粒与催化剂的接触形式直接影响炭颗粒的燃烧温度。     

DIESEL SOOT COMBUSTION WITH PEROVSKITE CATALYSTS

Diesel soot emissions from stationary or mobile sources can be reduced through physical trapping in particulate filters until periodical in situ combustion takes place. This study focuses on the development of several perovskites for the catalytic combustion of diesel particulates in multifunctional catalytic reactors. Several perovskites, with BET surface areas of 20–30 m²/g, were prepared by the solution combustion synthesis method and were characterized by XRD, SEM, TEM, and TPD techniques. Catalytic activity tests have shown that the most promising catalysts, namely, perovskite catalysts with Cr in the B site and Tb or Pr in the A site, can ignite soot combustion well below 400°C, i.e., at a temperature 200°–250°C lower than that of noncatalytic diesel soot combustion. The best catalytic formulation was deposited on a full-scale wall-flow filter and tested against the soot emissions of a diesel engine, resulting in reduced regeneration time and substantial fuel consumption saving compared to the corresponding bare filter performance.     

柴油车尾气四效组合催化剂的研究

提出设计双层组合催化剂净化新技术,即碳黑氧化燃烧催化剂床层和NOx还原催化剂床层的组合,该组合催化剂对柴油机尾气四种污染物的消除具有较高的催化活性。采用浸渍法制备了Al₂O₃负载不同量的La_0.8K_0.2MnO₃和相同负载量、不同K含量的La_1-xK_xMnO₃/Al₂O₃催化剂作为氧化催化剂处理碳烟、CO和HC;采用等体积浸渍法制备Cr/HZSM-5、Mo/HZSM-5、W/HZSM-5三系列催化剂作为还原催化剂处理NOx,并将其进行组合,得到优良的氧化还原组合催化剂,同时处理柴油车尾气中的四种污染物。在模拟柴油车尾气组成条件下,用乙炔代表烃类物质并采用固定床微型反应装置,考察了所制备的双层四效组合催化剂净化柴油车尾气的催化性能。研究发现,负载质量分数为50%的La_0.5K_0.5MnO₃/Al₂O₃和负载量为1.42×10^-4mol·g^-1的W/HZSM-5组合催化剂对于同时消除柴油车尾气NO、碳颗粒、CO和HC有较好的效果。NO还原为N₂的转化率在反应温度范围最高可达79%,同时碳颗粒的燃烧峰值温度为448 ℃,碳颗粒燃烧生成CO₂ 的最大选择性可达98%,乙炔完全转化的温度为364 ℃,从而实现了四种有害物质的同时催化净化。     

Effects of alkali metal cations on the structures, physico-chemical properties and catalytic behaviors of silica-supported vanadium oxide catalysts for the selective oxidation of ethane and the complete oxidation of diesel soot

A comparative study on the effects of alkali metal on the structures, physico-chemical properties and catalytic behaviors of silica-supported vanadium catalysts for the selective oxidation of ethane and the complete oxidation of diesel soot was reported.