负载型金催化剂上的CO氧化

在过去的10年中，由于含有微小的纳米级金的负载型金催化剂的特殊活性，因此对此催化剂的研究热情空前高涨。这种催化剂上的一氧化碳低温氧化已经得到深入研究。尽管研究的步伐在加快，但是如制备参数和催化活性的关系、活性中心的性质和反应的机理等的议题仍然是时下争论的课题。这些争论的解决需要进一步的研究。     

负载型纳米Au催化剂光催化性能的研究进展

金纳米颗粒对紫外和可见光有较好的吸收,能在温和条件下活化反应分子,从而促使反应发生,并提高反应物转化率和产物选择性,成为新型光催化剂的研究热点。本文介绍了纳米金催化剂的光催化反应机理,光子激发的表面等离子体共振所造成的表面电荷偶极引起亲电子或亲核反应,以及以半导体材料为载体的负载型纳米金催化剂光催化机理。总结了纳米金光催化剂在污染物和染料降解、臭氧分解、硝基化合物还原、选择氧化以及制氢等光催化领域的应用和最新研究进展,并展望了该新型光催化剂的研究发展方向。     

负载型Au催化剂的应用研究概述

本文概述了Au催化剂的研究进展，各类反应对Au催化剂的微观结构非常敏感，催化剂的活性与载体的种类，催化剂表面Au晶粒大小，载体与Au相互作用的强弱以及制备方法密切相关，载体主要包括各种氧化物和分子筛；表面Au粒子平均直径小于5nm，一般会有较好的催化活性，常用沉积－沉淀法或共沉淀法来制备，Au催化剂主要应用于CO低温氧化与丙烯环氧化等反应中。     

浅谈Au催化剂参与的催化反应

本文主要介绍了Au催化剂参与的催化反应,如CO的氧化、NOx的还原、烃类及有机挥发物(VOCS)的燃烧、低温水煤气变换反应以及新型燃料电池反应等,并对CO的氧化反应进行了详细的描述。     

负载型纳米金催化剂的研究进展

金是一种高化学惰性金属,其纳米粒子具有独特的结构和性质,在催化、光电传感器和生物医药等领域应用广泛。研究表明,负载在金属氧化物等载体上的纳米金粒子具有很高的催化活性,特别是在CO低温催化氧化中,催化效率明显高于其他类型贵金属。纳米金催化剂的研究已经具有了相当的深度和广度,在工业催化和环境保护等领域显现出重要的发展前景和商机。     

负载型非晶态合金催化剂研究进展

介绍了负载型非晶态合金催化剂制备技术和最新应用技术领域。阐述了溶胶－凝胶法技术制备非晶催化剂的基本原理、特性和活性比较；对非晶催化材料在不饱和化合物加氢等领域的应用情况进行了归纳总结。分析提出：研究功能载体、添加助催化剂或改性剂以及降低还原成本是研究非晶态催化剂制备技术的发展方向，在应用领域应首先加强在乙烯裂解馏分选择加氢除炔烃技术上的研究。     

低温CO催化氧化负载型Pd催化剂研究进展

综述了低温CO催化氧化负载型Pd催化剂在制备方法、载体的选用和催化机理等方面的研究进展,并介绍了该类催化剂的最新进展.在文章末对该催化剂领域尚待深入研究的问题进行了探讨.     

负载型Pd催化剂

介绍了制备负载型钯催化剂的几种方法,以及它在反应中的应用。阐述了几种催化剂载体的优点,最后对这种催化剂的前提提出展望。     

科学家发现新型催化剂制备途径

随着电化学制备催化剂方法的诞生，我国科学家最近合成了新型铂纳米材料催化剂，实现了在催化活性、稳定性和效率上的提高，这是我国在铂纳米材料催化剂制备方法上的重大突破。[第一段]     

二氧化铈载金催化剂催化CO氧化的研究进展

将金纳米颗粒负载在二氧化铈上,形成负载型催化剂,能应用于多种反应体系,表现出良好的催化活性,有着广阔的发展前景。综述了二氧化铈载金催化剂在一氧化碳催化氧化中的应用研究进展,介绍了二氧化铈载金催化剂中金的结构、价态和纳米尺寸,载体二氧化铈的形貌、结构、尺寸和氧空位以及金和载体二氧化铈两者之间的相互作用对一氧化碳催化氧化性能的影响。     

Preferential oxidation of carbon monoxide over Pt, Au monometallic catalyst, and Pt–Au bimetallic catalyst supported on ceria in hydrogen-rich reformate

The objective of this paper was to study a preferential oxidation (PROX) of carbon monoxide over monometallic catalysts including Pt, Au and Pt–Au bimetallic catalyst supported on ceria in hydrogen-rich reformate. Single step sol–gel method (SSG) and impregnation on sol–gel method (ISG) were chosen for the preparation of the catalysts. The characteristics of these catalysts were investigated by X-ray diffractometer (XRD), Brunauer–Emmet–Teller (BET) method, transmission electron microscope (TEM), scanning electron microscope (SEM) and temperature-programmed reduction (TPR). The XRD patterns of the catalysts showed only the peaks of ceria crystallite and no metal peak appeared. From TEM images, the active components were seen to be dispersed throughout the ceria support. The TPR patterns of PtAu/CeO₂ catalyst prepared by SSG showed the reduction peaks were within a low temperature range and therefore, the catalysts prepared by SSG exhibited excellent catalytic activity for preferential oxidation of CO. Bimetallic Pt–Au catalyst improved the activity (90% conversion and 50% selectivity at 90 °C) because of the formation of a new phase. When the metal content of (1:1) PtAu/CeO₂ catalyst prepared by SSG was increased, the CO conversion did not change much while the selectivity decreased in the low temperature range (50–90 °C). The CO conversion increased with increasing W/F ratio. The presence of CO₂ and H₂O had a negative effect on CO conversion and selectivity due to blocking of carbonate and water on active sites.     

活性炭负载的纳米金催化剂上葡萄糖氧化工艺

采用溶胶固定法制备了一系列的Au/C纳米催化剂,进行了透射电镜(TEM)表征,用于常压下以氧气为氧化剂碱性溶液中葡萄糖氧化制备葡萄糖酸钠,并对最佳的催化剂进行了反应条件影响考察。结果显示,使用溶胶固定法制备的质量分数为1%的Au/C催化效果最佳,纳米金颗粒直径小于2 nm且分布均匀,其较佳反应条件为50℃,pH 9.5,氧气流量40 mL/min,催化剂0.22 g,水溶液中质量分数为7.5%的葡萄糖,葡萄糖在1 h内,选择性及转化率均可同时达到100%,反应的转化频率(Turnover Frequency,TOF)高达1 560 h-1。上述研究表明溶胶固定法能制备一定纳米金颗粒大小的Au/C催化剂,且在该多相催化剂上反应时间短,活性高,选择性高。     

Infrared Study of the NO + CO Interaction over Au/TiO2 Catalyst

It was demonstrated that, in contrast to previous results, an NCO surface complex does form on Au/TiO₂ catalysts in the high-temperature reaction of NO + CO. By means of Fourier transform infrared spectroscopy two new absorption bands at 2285 and 2105-2210 cm^-1, not observed in separate adsorption of reacting gases, were detected during the catalytic reaction. The former is attributed to Au-NCO and the latter to Ti-NCO species. It was assumed that, similar to the case of supported Pt metals, NCO is primarily formed on Au crystallites and then spills over onto titania. This idea was strengthened by the results obtained following the adsorption of HNCO on the catalyst and on the support.     

聚合物固载催化剂的研究进展

介绍聚合物固载催化剂有6类,包括离子交换树脂催化剂,聚合物固载的相转移催化剂,聚合物固载的酸催化剂,聚合物固载的碱催化剂,聚合物固载的金属催化剂,聚合物固载的生物催化剂等。综述了近年来聚合物固载催化剂的研究进展。     

纳米复合催化剂的研究进展

简单介绍了纳米材料及纳米催化剂的特征与分类。综述了近年来国内外纳米复合催化剂的研究进展,包括纳米复合催化荆的结构与分类、制备方法、应用等。并对纳米复合催化剂的发展趋势进行了展望。     

合成气的工业应用与催化剂研究进展

详细介绍了合成气制备液体燃料、低碳烯烃、含氧化合物和其他化学品的工业应用情况,同时,综述了其工业应用中所使用的催化剂研究进展和新型催化剂的开发情况,并指出今后应进一步推进实用技术,加快工业化。     

Low temperature CO oxidation over Au/TiO2 and Au/SiO2 catalysts

After a high-temperature reduction (HTR) at 773 K, TiO₂-supported Au became very active for CO oxidation at 313 K and was an order of magnitude more active than SiO₂-supported Au, whereas a low-temperature reduction (LTR) at 473 K produced a Au/TiO₂ catalyst with very low activity. A HTR step followed by calcination at 673 K and a LTR step gave the most active Au/TiO₂ catalyst of all, which was 100-fold more active at 313 K than a typical 2% Pd/Al₂O₃ catalyst and was stable above 400 K whereas a sharp decrease in activity occurred with the other Au/TiO₂ (HTR) sample. With a feed of 5% CO, 5% O₂ in He, almost 40% of the CO was converted at 313 K and essentially all the CO was oxidized at 413 K over the best Au/TiO₂ catalyst at a space velocity of 333 h^–1 based on CO + O₂. Half the chloride in the Au precursor was retained in the Au/TiO₂ (LTR) sample whereas only 16% was retained in the other three catalysts; this may be one reason for the low activity of the Au/TiO₂ (LTR) sample. The reaction order on O₂ was approximately 0.4 between 310 and 360 K, while that on CO varied from 0.2 to 0.6. The chemistry associated with this high activity is not yet known but is presently attributed to a synergistic interaction between gold and titania.     

分子筛型超强酸催化剂的研究新进展

分子筛超酸为一种同时具备分子筛和超强酸的特性的新型催化材料，在此介绍了这类催化剂的最新研究情况。着重介绍这类催化剂合成和表征技术，展望了它的应用前景，并提出了今后研究的一些设想。     

合成丙酸催化剂的研究进展

通过对国内外乙烯羰基化和乙醇羰基化制丙酸催化剂的研究进展进行综述,并提出了羰基化法合成丙酸催化剂研究发展的新思路。