Cooperative adsorbate binding catalyzes high-temperature hydrogen oxidation on palladium

• 成果类型: Article
• 署名作者: Schwarzer, Michael; Borodin, Dmitriy; Wang, Yingqi; Fingerhut, Jan; Kitsopoulos, Theofanis N.; Auerbach, Daniel J.; Guo, Hua; Wodtke, Alec M.
• 署名单位: University of Gottingen; University of New Mexico; University of Southern Mississippi
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-9767
• DOI: 10.1126/science.adk1334
• 发表日期: 2024-11-01
• 页码: 511-516
• 关键词: total-energy calculations; finding saddle-points; adsorption; oxygen; co; pd; energetics; reduction; mechanism; relevant

摘要

Atomic-scale structures that account for the acceleration of reactivity by heterogeneous catalysts often form only under reaction conditions of high temperatures and pressures, making them impossible to observe with low-temperature, ultra-high-vacuum methods. We present velocity-resolved kinetics measurements for catalytic hydrogen oxidation on palladium over a wide range of surface concentrations and at high temperatures. The rates exhibit a complex dependence on oxygen coverage and step density, which can be quantitatively explained by a density functional and transition-state theory-based kinetic model involving a cooperatively stabilized configuration of at least three oxygen atoms at steps. Here, two oxygen atoms recruit a third oxygen atom to a nearby binding site to produce an active configuration that is far more reactive than isolated oxygen atoms. Thus, hydrogen oxidation on palladium provides a clear example of how reactivity can be enhanced on a working catalyst.