The nature of electrophilic oxygen: Insights from periodic density functional theory investigations

SURFACE SCIENCE

卷:679

Article

Kenge, Nivedita¹  Pitale, Sameer^1,2  Joshi, Kavita^1,2 

[1] CSIR Natl Chem Lab, Phys & Mat Chem Div, Pune 411008, Maharashtra, India

[2] Acad Sci & Innovat Res AcSIR, 2 Rafi Marg, New Delhi 110001, India

关键词: Epoxidation;    Ag(100);    DFT;    Electrophilic;    Nucleophilic oxygen;   

DOI  :  10.1016/j.susc.2018.09.009

来源: Elsevier

【 摘 要 】

Increasing demand of ethylene oxide and the cost of versatile chemical ethene has been a driving force for understanding mechanism of epoxidation to develop highly selective catalytic process. Direct epoxidation is a proposed mechanism which in theory provides 100% selectivity. A key aspect of this mechanism is an electrophilic oxygen (O-ele) species forming on the Ag surface. In the past two and half decades, large number of theoretical and experimental investigations have tried to elucidate formation of O-ele, on Ag surface with little success. Equipped with this rich literature on Ag-O interactions, we investigate the same using periodic DFT calculations to further understand how silver surface and oxygen interact with each other from a chemical standpoint. Based on energetics, Lowdin charges, topologies and pdos data described in this study, we scrutinize the established notions of O-ele. Our study provides no evidence in support of O-ele, being an atomic species nor a diatomic molecular species. In fact, a triatomic molecular species described in this work bears multiple signatures which are very convincing evidence for considering it as the most sought for electrophilic entity.

【 授权许可】

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