SusChEM: Energies of Adsorbed Catalytic Intermediates on Transition Metal Surfaces

在这个由化学催化计划资助的项目中，华盛顿大学的查尔斯·T·坎贝尔正在开发更好的催化剂，用于生产散装化学品、化肥和燃料，用于污染清除，以及燃料的燃烧。这项工作涉及对燃料电池或环境应用中经常遇到的小原子团在铜、镍和铂等通常用作催化剂的金属表面的受控吸附。当这些通常只含有碳、氢和氧的小原子团吸附到金属表面时，就形成了化学键。研究人员正在使用一种著名的量热技术来测量这些化学键的强度。实验测量结果存储在一个数据库中，供计算科学家使用，他们将对这些表面或其他环境中可能发生的化学反应进行模拟。因此，这项工作通过创造一个其他科学家可以利用和使用的公共资源，产生了广泛的影响。它提供了设计更好的催化剂所需的基本知识，以便以更高的能源效率和更少的污染进行具有工业重要性的化学反应，从而产生了进一步广泛的影响。这项工作是为了帮助设计更好的电池和燃料电池，可以集成到太阳能和风能系统中。这个项目专注于对吸附在单晶镍、铜和铂表面的明确定义的催化反应中间体(特别是-OH、-OCH3、-OOCH、-CH3和-CH)的能量进行量热测量。它们代表了催化反应机制中最常见的五种吸附类别，当它们组合在一起时，它们提供了与能源有关的和环境催化过程中发生的许多基本步骤的能量。这反过来又阐明了催化中反应机理和结构-反应性关联的能量基础。坎贝尔正在与斯坦福大学的延斯·诺尔斯科夫合作，将这些测量结果与之前的文献结合起来，创建一个可靠的吸附能量基准数据库。这个数据库将帮助理论家开发计算方法，以提高能量精度计算表面反应的能量学。尽管周期边界条件下的密度泛函理论(DFT)在催化研究中已经非常成功，但该方法仍然受到吸附中间体相对能量的较大误差的困扰。该数据库的建设正在促进理论和计算化学界正在进行的努力，以提高这些快速计算方法的能量准确性。这也有助于其他研究人员更充分地了解过渡金属催化中反应机理和结构-活性关联的能量基础。

In this project, funded by the Chemical Catalysis Program, Charles T. Campbell of the University of Washington is developing better catalysts for use in the production of bulk chemicals, fertilizers and fuels, for pollution cleanup, and for the combustion of fuels. The work involves the controlled adsorption of small groups of atoms that are often encountered in fuel cells or environmental applications to metal surfaces that are commonly used as catalysts, such as copper, nickel and platinum. When these small clusters of atoms, usually containing only carbon, hydrogen and oxygen, adsorb to a metal surface, a chemical bond is formed. The investigators are measuring the strength of these chemical bonds using a well-known technique known as calorimetry. The experimental measurements are stored in a database that is being made available to computational scientists who will perform simulations of chemical reactions that could potentially be occurring on these surfaces or in other settings. The work is, thus, having a broad impact through the creation of a publicly available resource that other scientists can take advantage of and use. It is having a further broad impact by providing the basic understanding needed to design better catalysts in order to carry out industrially important chemical reactions with higher energy efficiency and less pollution. This work is aiding the design of better batteries and fuel cells that can be integrated into solar and wind energy systems.This project is focused on calorimetric measurements of the energies of well-defined catalytic reaction intermediates (specifically -OH, -OCH3, -OOCH, -CH3 and -CH) adsorbed on single-crystal Ni, Cu and Pt surfaces. These represent five of the most common adsorbate classes evoked in catalytic reaction mechanisms, and when combined, they provide the energetics of many elementary steps that occur during energy-related and environmental catalysis. This, in turn, elucidates the energetic basis for reaction mechanisms and structure-reactivity correlations in catalysis. Campbell is collaborating with Jens Nørskov of Stanford University to combine these measurements with prior literature to create a benchmark database of reliable adsorption energies. This database will help theoreticians develop computational methods for calculating the energetics of reactions at surfaces with improved energy accuracy. While density functional theory (DFT) with periodic boundary conditions has been extremely successful in catalysis research, the method is still plagued by rather large errors in the relative energies of the adsorbed intermediates. The construction of this database is facilitating ongoing efforts in the theoretical and computational chemistry community to improve the energy accuracy of these fast computational methods. It is also aiding other researchers who seek to understand more fully the energetic basis for reaction mechanisms and structure-activity correlations in transition metal catalysis.