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

本文制备了分散在三种同素异构型碳上的CTS-9415335 M.Albert Vannice铜微晶，并对其进行了表征，考察了其对共轭体系选择性加氢和一氧化二氮分解的催化性能。在高比表面积的石墨化碳纤维、金刚石薄膜和活性无定形碳上放置非常小和很大的铜颗粒。研究了前处理对铜粉颗粒大小、形貌和化学状态的影响。利用可控气氛电子显微镜(CAEM)、高分辨率电子显微镜、化学吸附、X射线衍射、漫反射傅立叶变换红外光谱(DRIFTS)、电子自旋共振(ESR)和铜-63固体核磁共振对其进行了表征。用微波技术测量碳的电子能力和电导率，以测量预处理对三种形态碳的电学性质的影响以及吸附小分子的影响。测试反应包括将呋喃甲醛加氢成呋喃甲醛，将克隆醛加氢成巴豆醇，以及分解一氧化二氮。并对工业铜铬矿催化剂进行了对比研究。确定了铜微晶尺寸和碳载体类型对比活性的影响。这些新的铜/碳催化剂有三个潜在的重要工业应用：替换商业铜铬催化剂，因为废铬催化剂是一种危险废物，是一个处理问题；开发新的铜催化剂，以减少选择性加氢产生的有害副产品；以及分解一氧化二氮，这是一种温室气体，在某些工业过程中产生副产品，如生产己二酸，尼龙的前体。该奖项是无害环境的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. ***