US-Austria Cooperative Research: Surface Chemistry Catalytic Properties and Support Effects on Pt/Ni and Pt/Co Bimetallic Catalysts

该奖项支持耶鲁大学化学系的加里·L·哈勒与奥地利维也纳理工大学物理化学研究所约翰尼斯·A·勒彻的研究合作。这些科学家都对双金属催化剂的表面化学感兴趣，特别是铂/镍和铂/钴，它们的催化和其他化学性质差异很大。他们合作研究的目的是了解载体效应在非零价金属物种稳定和氢吸收-脱附平衡中的作用。将使用几个支架。催化剂将用化学方法和物理方法进行表征，如X射线衍射、扩展X射线吸收精细结构(EXAFS)分析、时间分辨傅立叶变换红外光谱(FTIR)等，氢吸附/脱附速率、平衡等温线和几个加氢反应将被用作化学探针。合作安排通过利用物理表征方面的互补专业知识(美国的EXAFS和奥地利的时间分辨FTIR光谱)以及在两个实验室对相同催化剂进行不同反应研究的分工，加快了这项工作。虽然过渡金属是加氢反应中最常用的催化剂之一，但人们充其量只能定性地了解它们在更复杂的有机分子加氢中具有高活性和特殊选择性的原因。人们提出了许多概念来解释它们的选择性，包括这些合作的科学家独立开展的工作，这些工作表明，载体对吸氢平衡的影响以及非零价金属中心的存在可能会极大地影响加氢反应的选择性。联合研究的目标之一是确定这两个因素的相对重要性。了解和控制这些性质可能会显著提高加氢反应的活性和选择性。

This award supports Gary L. Haller of the Department of Chemical Engineering, Yale University, in a research collaboration with Johannes A. Lercher, Institute for Physical Chemistry, Technical University of Vienna, Austria. These scientists share an interest in the surface chemistry of bimetallic catalysts, particularly platinum/nickel and platinum/cobalt which vary significantly in their catalytic and other chemical properties. The goal of their collaborative research is to understand the role of support effects on stabilization of non-zero valent metal species and on hydrogen absorption-desorption equilibrium. Several supports will be used. Catalysts will be characterized by chemical methods and by physical methods such as x-ray diffraction, extended x-ray absorption fine structure (EXAFS) analysis, time resolved Fourier transform infrared (FTIR) spectroscopy, etc. The rates of hydrogen absorption/desorption, the equilibrium isotherm and several hydrogenation reactions will be used as chemical probes. The collaborative arrangement expedites this work by bringing to bear complementary expertise in physical characterization (EXAFS on the US side and time resolved FTIR spectroscopy on the Austrian side) as well as a division of labor in carrying out different reaction studies on the same catalysts in the two laboratories. Although transition metals are among the most frequently used catalysts for hydrogenation reactions, the reasons for their high activity and for particular selectivities in hydrogenation of more complex organic molecules are, at best, only qualitatively understood. Numerous concepts have been proposed to explain their selectivity, including work carried out independently by these collaborating scientists which showed that support effects on hydrogen absorption equilibrium and the presence of non-zero valent metal sites may greatly affect the selectivity of hydrogenation reactions. One of the objectives of the joint research is to establish the relative importance of these two factors. Understanding and manipulating these properties may lead to significant improvements in the activity and selectivity of the hydrogenation reactions.