Mechanistic Insights into Covalent and Ionic Contributions to Molecular Adsorption and Reaction on Transition Metals

催化是一种化学物质为反应物(原料)提供一条新的、更容易产生更理想产品的途径的过程。催化化学品可以极大地提高反应速度，使反应在更温和、更可控的条件下进行，并提高对预期产品的选择性(副产品较少)。目前，为特定的、理想的反应开发良好的催化剂是具有挑战性的，并且需要对反应物和催化剂如何相互作用有很好的了解。在这个项目中，彭振梦博士正在研究决定一氧化碳(CO)氧化催化中过渡金属反应物-催化剂相互作用的关键因素。彭博士的方法是改进一个吸附模型，以便从易于进行的测量中准确地计算这些相互作用。在这项研究中获得的知识有助于显著加快寻找新催化剂的速度。催化在化工、石油化工和能源等行业中起着至关重要的作用，催化材料被广泛应用于化学转化和能源生产，具有广泛的社会影响。彭博士还积极参与了一系列外展活动，旨在培养高中生对早期科学的兴趣，并影响他们在科学、技术、工程和数学(STEM)领域的职业发展。他参与了为K-12教师开发纳米催化学习模块，指导本科生和研究生，开发社区学习网络课程，以及与阿克伦大学的工程女性(WIE)和增加工程学术(IDEA)项目的多样性拓展努力。他们还指导本科生和研究生，为他们在需要化学和工程知识的领域未来的职业生涯做好准备。在化学系化学催化项目的资助下，阿克伦大学的彭振蒙博士正在使用易于测量的催化剂参数开发一个改进的d带吸附能理论(EAD)模型。他正在使用一氧化碳氧化的多途径机制研究来测试这一改进。为此，彭博士正在合成具有可控d带中心和功函数参数的模型催化剂，并考察它们与CO和O2吸附的相关性。这项研究使用反应物种的EAD来获得关于反应机理和其他重要催化性质的信息，这些信息在实验上是具有挑战性的。建立准确的EAD-催化剂参数关系使彭博士能够表征金属衬底上的吸附和活性中间体键合，了解这些参数关系有助于了解催化机理，识别活性中间体，并指导催化剂研究。假设在d带理论中隐含共价和离子贡献可以显著提高理论的精确度，彭博士将金属d带中心和功函数分别与EAD关联，以包含共价和离子部分。在这项研究中获得的知识有助于显著加快寻找新催化剂的速度。催化在化工、石油化工和能源等行业中起着至关重要的作用，催化材料被广泛应用于化学品转化和能源生产，具有广泛的社会影响。彭博士积极参与了多项外展活动，以支持该项目的更广泛影响，教育学生并提高公众对化学知识和技术的兴趣。外联活动特别针对K-12学生和代表性不足的少数族裔学生。

Catalysis is a process in which one chemical substance provides a new and easier pathway for reactant (feedstock) chemicals to produce more desirable products. Catalytic chemicals can greatly enhance the reaction rates, which allows the reactions to proceed under milder and more controllable conditions, and improves the selectivity to the desired product (fewer by-products). Currently, developing a good catalyst for a specific, desirable reaction is challenging and requires good knowledge of how the reactants and catalyst interact. In this project, Dr. Zhenmeng Peng is researching the key factors that determine reactant-catalyst interactions for transition metals in carbon monoxide (CO) oxidation catalysis. Dr. Peng's approach is to improve upon an adsorption model for accurate calculation of these interactions from easy to perform measurements. Knowledge gained in this research helps to significantly accelerate the search for new catalysts. Catalysis plays an essential role in chemical, petrochemical and energy industries, with catalytic materials being widely used for chemical conversions and energy generation, and thus the research has broad societal impact. Dr. Peng is also actively engaged in a number of outreach activities, aimed at creating early scientific interest in high school students and influencing their career development in science, technology, engineering and mathematics (STEM) fields. He is involved in the development of a nanocatalysis learning module for K-12 teachers, mentoring of undergraduate and graduate students, development of a community learning network course, and diversity outreach efforts with Women in Engineering (WIE) and Increasing Diversity in Engineering Academics (IDEA) programs at the University of Akron. THe also mentors undergraduate and graduate students, preparing them for future careers in areas that require chemistry and engineering knowledge.With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. Zhenmeng Peng at the University of Akron is developing an improved model of d-band theory of adsorption energy (Ead) using readily-measured catalyst parameters. He is using a multi-approach mechanistic study of carbon monoxide oxidation to test this improvement. To this aim, Dr. Peng is synthesizing model catalysts with a controlled d-band center and work function parameters and examining their correlations with CO and O2 adsorption. The research employs Ead of the reacting species to obtain information on the reaction mechanism and other important catalytic properties which are challenging to measure experimentally. Establishing an exact Ead-catalyst parameter relationship allows Dr. Peng to characterize adsorbate and reactive intermediate bonding to the metal substrate, the knowledge of which helps to understand the catalytic mechanism, identify reactive intermediates, and guide catalyst research. Driven by the hypothesis that implicit inclusion of both covalent and ionic contributions to d-band theory can significantly improve the accuracy of the theory, Dr. Peng relates the metal d-band center and work function to Ead for inclusion of the covalent and ionic fractions, respectively. Knowledge gained in this research helps to significantly accelerate the search for new catalysts. Catalysis plays an essential role in chemical, petrochemical and energy industries, with catalytic materials being widely used for chemicals conversion and energy generation, and thus the research has broad societal impact. Dr. Peng is actively engaged in a number of outreach activities, in support of the broader impacts of the project, to educate students and improve the public interest in chemistry knowledge and technology. K-12 students and underrepresented minority students are particularly targeted in the outreach activities.