Density Functional Theory Study on the Epoxidation of Propylene on Ag(100) Surface With Oxygen Coverage

ABSTRACT Propylene oxide (PO) is a crucial chemical intermediate, but its conventional production methods come with several limitations. In contrast, the propylene gas phase epoxidation process has garnered significant interest due to its environmentally friendly approach, utilizing cost‐effective and readily available raw materials and producing water as the sole byproduct. This study employs density functional theory to systematically explore catalytic propylene epoxidation on the Ag(100) surface. By systematically examining the effect of varying oxygen coverages on the Ag(100) surface, the research determines the saturation oxygen coverage through successive oxygen atom adsorption. Furthermore, it assesses the propylene epoxidation reaction at different oxygen coverage levels on the same surface. During this process, two parallel reaction pathways are studied: α‐H‐stripping to produce acrolein and the formation of a metal‐epoxide intermediate (OMMP2) through epoxidation, which further produces PO and acetone (AC). For the primary competitive reaction, a lower oxygen coverage favors the first step of α‐H abstraction, while the opposite is true for the epoxidation process; for the secondary competitive reaction, increasing the oxygen coverage favors the formation of PO and AC. The findings reveal that oxygen exposure substantially affects the primary competitive response and also exerts a considerable influence on the secondary competitive process. The second α‐H abstraction to produce acrolein requires higher activation energy compared to the secondary competitive reaction producing PO, thus making PO more likely to be formed than acrolein as the oxygen coverage increases.