Atomic insights into hydrogen peroxide decomposition on the surface of pure and pre-treated silver: A reactive molecular dynamics simulation study

• Published in: Applied surface science Vol. 644; p. 158701
• Main Authors: Zhao, Xiao, Feng, Yiming, Zhang, Bowei, Jin, Hui, Wei, Xianggeng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.01.2024
• Subjects: Hydrogen peroxide decomposition; Pretreatment; ReaxFF MD simulation; Silver-based catalyst; Surface reaction; Surface reaction; Hydrogen peroxide decomposition; Pretreatment; ReaxFF MD simulation; Silver-based catalyst
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2023.158701

[Display omitted] •The decomposition of H2O2 on pure and pre-treated silver catalyst is studied by ReaxFF MD.•The pretreatment causes Ag2O to be formed on the catalyst surface.•A four-stage HOOH bond break mechanism is found for both catalysts but requires different time.•The activation energy of pre-treated catalyst is about 50 % lower than pure silver catalyst.•Redundant hydrogen and oxygen atoms are deposited to block the active sites. Based on ReaxFF molecular dynamics simulation, H2O2 decomposition on pure and pre-treated silver catalyst is studied at a microscopic level. The pretreatment undergoes a surface annealing with redundant H2O2 on top of catalyst. The simulation results indicate that H2O2 decomposition can be drastically accelerated by elevating temperature. The extent of decomposition is closely related to bond, hydrogen bond, and potential energy of simulation system. It is found that H2O2 decomposition follows a four-stage HOOH bond break mechanism while it needs three times longer for pre-treated silver catalyst than pure silver catalyst. The activation energy of pre-treated silver catalyst is about 50 % lower than pure silver catalyst. However, the overall reaction rate of pre-treated silver catalyst is about an order of magnitude slower than pure silver catalyst, which owes to the much smaller pre-factor. It is believed that although the pretreatment causes silver oxide to be formed on the surface, it leads to more hydrogen and oxygen atoms deposited so that most active sites for catalytic reaction are blocked for further decomposition. This may be helpful to understand the inherent mechanism of H2O2 decomposition on silver-based catalyst and provide instructional advice for further catalyst modification design.