Acetylene Hydrogenation on Alloy Catalysts Spanning Ternary Alloy Composition Space

催化剂用于加速工业过程中的化学品生产，大大提高了生产效率，并在化学品制造中节省了大量能源。 多组分合金，两种或多种金属的均匀混合物，在这些反应中用作催化剂，因为它们比任何纯金属组分本身更有效。 相对金属组成在宽范围内是可变的，这在设计合金催化剂中提出了在寻找用于最大催化剂效率的每种金属组分的最佳相对量方面的挑战。这可能会成为一项繁琐而耗时的研究活动，因为它需要制备、表征和评估数百种不同的合金催化剂，每种催化剂都具有不同的组成。Gellman博士发明了一种快速、高通量的方法，以加速对多种可能组成的三组分（三元）合金催化剂的研究。 Gellman博士制造了一种单一材料，其中合金的成分沿材料表面连续沿着变化。 然后，他使用了一些最先进的空间解析分析工具。 每次测量探测具有不同组成的催化剂合金。 该方法允许一次制备100种催化剂组合物，然后在顺序制备每种组合物所允许的一小部分时间内进行表征和研究。 Gellman博士正在使用他的高通量方法来了解合金催化剂的组成如何影响乙炔（HCCH）加氢制乙烯（H2 CCH 2）的动力学和选择性，这是聚合物生产中的一个重要化学过程。最终，Gellman博士的工作可能会导致合金催化剂在许多应用中的改进，并可能有助于清洁能源技术的碳氢化合物转化。 除了他在催化领域的进步外，盖尔曼博士还在与学生的工作中产生了更广泛的影响。 他指导女本科生进行研究，以鼓励她们在STEM领域攻读高级学位的兴趣。 作为卡内基梅隆大学斯科特能源创新研究所的联合主任，他还参与了公共教育活动。了解多组分合金催化剂的复杂性是由测量合金材料的物理特性和催化活性作为多维组成的函数的实验挑战所混淆的。在化学部化学催化计划和化学，生物工程，环境和运输系统部的催化和生物催化计划的资助下，卡内基梅隆大学的Andrew Gellman博士通过使用一套独特的高通量方法解决了这一挑战。 该分析采用了一种合金膜，该合金膜包含合金的所有可能成分，其过程称为成分扩散合金膜（CSAF）。 三元合金，CuxAuyPd 1-x-y，CuxAgyPd（1-x-y），和AgxAuyPd（1-x-y），制造与x和y变化的整个组成范围内的一个约1平方厘米的面积的样品尺寸。 空间分辨表面分析工具用于映射合金特性，包括本体组成、表面组成和价电子结构，作为组成空间的函数。 一个独特的，100通道的微反应器阵列，然后用于并行测量的动力学和选择性的几个催化过程，HD交换，乙烯加氢和乙炔加氢，在100个不同的合金组合物。 微观动力学分析是用来提取基本的机械步骤的基本反应参数。这些测量建立了动力学参数和合金特性之间的相关性，并深入了解各个基本步骤与合金成分的速率依赖性。 除了他在催化领域的进步外，盖尔曼博士还在与学生的工作中产生了更广泛的影响。 他指导本科女生进行研究，以鼓励她们对在STEM领域攻读高级学位的兴趣。 他还参与公共教育活动，作为卡内基梅隆大学斯科特能源创新研究所联合主任的一部分。

Catalysts are used to accelerate production of chemicals in industrial processes, greatly increasing the efficiency of production and providing significant energy savings in chemical manufacturing. Multicomponent alloys, homogeneous mixtures of two or more metals, are used as catalysts in these reactions because they are more effective than any of the pure metal components by itself. The relative metal compositions are variable over a wide range, which presents a challenge in designing alloy catalysts in finding the optimal relative amounts of each metal component for maximum catalyst efficiency. This can become a tedious and time-consuming research activity because it requires the preparation, characterization and catalytic evaluation of hundreds of different alloy catalysts, each with a different composition. Dr. Gellman has invented a rapid, high-throughput method to accelerate the study of three-component (ternary) alloy catalysts over a wide range of possible compositions. Dr. Gellman fabricates a single material in which the composition of the alloy is varied continuously along the material surface. He then uses a number of state-of-the-art spatially-resolved analytical tools. Each measurement probes a catalyst alloy with a different composition. This methods allows 100 catalyst compositions to be prepared at once, then characterized and studied in a fraction of the time that sequential preparation of each composition would allow. Dr. Gellman is using his high-throughput method to understand how the composition of alloy catalysts influences the kinetics and selectivity of acetylene (HCCH) hydrogenation to ethylene (H2CCH2), an important chemical process in polymer production. Ultimately, Dr. Gellman's work may lead to improvement of alloy catalysts for numerous applications and may contribute to clean energy technologies for its relevance to hydrocarbon conversion. In addition to his advancement of the field of catalysis, Dr. Gellman is making broader impacts in his work with students. He mentors female undergraduate students in research to encourage their interest in pursuing advanced degrees in the STEM fields. He also is engaged in public education activities as part of his role as co-Director of the Carnegie Mellon University's Scott Institute for Energy Innovation.Understanding the complexity of multicomponent alloy catalysts is confounded by the experimental challenges of measuring the physical characteristics and the catalytic activities of alloy materials as a function of multidimensional composition. With funding from the Chemical Catalysis Program of the Chemistry Division and the Catalysis and Biocatalysis Program of the Division of Chemical, Bioengineering, Environment and Transport Systems Division, Dr. Andrew Gellman of Carnegie Mellon University addresses this challenge by using a unique set of high-throughput methods developed in his lab. The analysis employs an alloy film containing all possible compositions of alloys in a process called Composition Spread Alloy Films (CSAF). Ternary alloys, CuxAuyPd1-x-y, CuxAgyPd(1-x-y), and AgxAuyPd(1-x-y), are fabricated with x and y varied over the entire compositional range within an approximately 1 cm2 area sample size. Spatially resolved surface analysis tools are used to map alloy characteristics, including bulk composition, surface composition and valence electronic structure, as a function of composition space. A unique, 100 channel microreactor array is then used to make parallel measurements of the kinetics and selectivities of several catalytic processes, HD exchange, ethylene hydrogenation and acetylene hydrogenation, at 100 different alloy compositions. Microkinetic analysis is used to extract the fundamental reaction parameters for elementary mechanistic steps. These measurements establish correlations among kinetic parameters and alloy characteristics and yield insight into rate dependence of individual elementary steps with alloy composition. In addition to his advancement of the field of catalysis, Dr. Gellman is making broader impacts in his work with students. He mentors undergraduate female students in research to encourage their interest in pursuing advanced degrees in the STEM fields. He also is engaged in public education activities as part of his role as co-Director of the Carnegie Mellon University's Scott Institute for Energy Innovation.