The Preparation and Characterization of Well-Dispersed Copper/Carbon Systems for Use as Selective Hydrogenation and Nitrous-Oxide Decomposition Catalyst

摘要制备了分散在三种同素异形体碳上的铜晶体，对其进行了表征，并对其作为共轭体系选择性加氢和氧化亚氮分解的催化剂进行了研究。非常小和非常大的铜颗粒被放置在高表面积石墨化碳纤维、金刚石薄膜和活性无定形碳上。研究了预处理对铜颗粒大小、形貌和化学状态的影响。表征是通过可控气氛电子显微镜（CAEM）、高分辨率透射电子显微镜、化学吸收、x射线衍射、漫反射傅里叶变换红外光谱（DRIFTS）、电子自旋共振（ESR）和铜-63固态核磁共振完成的。利用微波技术测量碳的电子能力和电导率，测定预处理对三种形式碳的电学性能的影响以及吸附小分子的影响。试验反应包括糠醛加氢制糠醇、克朗东醛加氢制丁醇和氧化亚氮分解。对一种商品铜铬铁矿催化剂进行了比较研究。测定了铜晶粒尺寸和碳载体类型对比活度的影响。这些新的铜/碳催化剂有三个潜在的重要工业应用：取代商用铜-铬铁矿催化剂，因为废铬铁矿催化剂是一种危险废物，因此需要处理；新型铜催化剂的开发，以减少选择性氢化过程中的有害副产物；一氧化二氮的分解，一种温室气体，在某些工业过程中作为副产品产生，如生产尼龙的前体己二酸。该奖项是环保化学合成和加工倡议的一部分。＊＊＊

ABSTRACT CTS-9415335 M. Albert Vannice Copper crystallites dispersed on three allotropic forms of carbon are prepared, characterized, and examined as catalysts for selective hydrogenation of conjugated systems and decomposition of nitrous oxide. Both very small and large copper particles are placed on high-surface-area graphitized carbon fibers, diamond films, and activated amorphous carbon. The influence of pretreatment on the size, morphology, and chemical state of the copper particles is investigated. Characterization is accomplished using controlled-atmosphere electron microscopy (CAEM), high-resolution transmission electron microscopy, chemisorption, X-ray diffraction, diffuse-reflectance Fourier-transform infrared spectroscopy (DRIFTS), electron spin resonance (ESR), and copper-63 solid-state nuclear magnetic resonance. Microwave techniques to measure the electron ability and conductivity of carbon are used to guage the effect of pretreatment on the electrical properties of the three forms of carbon and the influence of small adsorbed molecules. Test reactions include hydrogenation of furfural to furfurol, hydrogenation of crontonaldehyde to crotyl alcohol, and decomposition of nitrous oxide. A commercial copper-chromite catalyst is studied for comparison. The effects of copper crystallite size and type of carbon support on specific activity are determined. These new copper/carbon catalyst have three potentially significant industrial applications: replacement of commercial copper-chromite catalyst because spent chromite catalysts are a hazardous waste and hen e a disposal problem; development of new copper catalysts to reduce unwanted byproducts from selective hydrogenations; and decomposition of nitrous oxide, a greenhouse gas, produced as a byproduct in certain industrial processes such as production of adipic acid, a precursor of nylon. This award is part of the Environmentally Benign Chemical Synthesis and Processing Initiative. ***