Mechanistic Insights into the Structure Sensitivity of Hydrocarbon Conversions Catalyzed by Metal Surfaces

在这个由化学部化学催化项目资助的项目中，加州大学河滨分校的Francisco Zaera教授正在研究碳氢化合物在金属表面从一种化合物转化为另一种化合物的分子过程，也称为催化。碳氢化合物转化反应的催化作用是许多工业过程的核心，包括炼油、精细化学合成和食品加工。催化的主要挑战之一是实现一种产品对所有其他潜在产品的高选择性，这将避免浪费原料并最大限度地减少污染副产品的产生。研究表明，在金属表面的某些催化中，选择性可以通过表面原子水平结构的变化来控制，这种控制为设计高度理想的工业过程提供了新的途径。在这个项目中，Zaera教授专注于测试特定的例子，在这些例子中，可以通过使用具有特定形状的金属纳米颗粒来控制碳氢化合物的转化。正在使用三种互补的实验方法：一个高通量分子束，用于在受控环境下获得不同结构的模型金属样品的精确动力学参数；一个operando排列，用于通过红外光谱原位表征相应的吸附物质；一个反应器，用于表征由具有特定形状的金属纳米颗粒分散在高表面积载体上制成的更现实的催化剂的动力学和红外表征。该项目涉及研究生的培训，重点是利用若干国际外联活动从科学研究领域代表性不足的群体中招收学生。该项目的更广泛影响还包括为能源和其他应用开发更清洁的催化过程的潜力。

In this project funded by the Chemical Catalysis program of the Chemistry Division, Professor Francisco Zaera of the University of California, Riverside is investigating the molecular processes by which hydrocarbons are converted from one compound to another on the surface of a metal, also termed catalysis. The catalysis of hydrocarbon conversion reactions is central to many industrial processes, including oil refining, fine chemical synthesis, and food processing. One of the major challenges in catalysis is to achieve high selectivity for one product over all other potential products, which would avoid wasting feedstocks and would minimize the production of polluting byproducts. It has been shown that, in some catalysis on metal surfaces, selectivity may be controlled through variations in the atomic level structure of the surface, and this control offers new avenues for the design of highly desirable industrial processes. In this project, Professor Zaera focuses on testing specific examples where hydrocarbon conversion may be controlled by using metal nanoparticles with specific shapes. Three complementary experimental approaches are being used: a high-flux molecular beam to obtain accurate kinetic parameters for model metal samples with different structures under controlled environments, an operando arrangement for the in-situ characterization of corresponding adsorbed species by infrared (IR) spectroscopy, and a reactor for the kinetic and IR characterization of more realistic catalysts made out of metal nanoparticles with specific shapes dispersed on high-surface-area supports. This project involves the training of graduate students, with an emphasis in recruiting students from groups underrepresented in science research fields by taking advantage of the several international outreach activities. The broader impacts of this project also include the potential development of cleaner catalytic processes for energy and other applications.