Electron transfer enhancing the Mn(II)/Mn(III) cycle in MnO/CN towards catalytic ozonation of atrazine via a synergistic effect between MnO and CN. (15th February 2023)

• Record Type: Journal Article
• Authors: Wang, Da; He, Yinning; Chen, Yi; Yang, Fan; He, Zhiqiao; Zeng, Tao; Lu, Xiaohui; Wang, Lizhang; Song, Shuang; Ma, Jun
• Is Part Of: Water research. Volume 230(2023)
• Publication Date: 2023-02-15
• Subjects: Catalytic ozonation -- MnO -- CN -- Synergistic effect -- Atrazine; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2023.119574
• Languages: English
• ISSNs: 0043-1354

Abstract

Highlights: Manganese oxide (MnO) dispersed on CN (Mn-nCN) was fabricated. Excellent HCO performance achieved via the synergistic effects between MnO and CN. Electron-rich Mn(Ⅱ) sites and electron-poor CN sites were the main active sites. C–N–Mn and C–O–Mn bonds assisted the cycle of Mn(II)/Mn(III) during HCO. Abstract: In this study, manganese oxide (MnO) dispersed on CN (Mn- n CN) was fabricated as a catalyst in heterogeneous catalytic ozonation (HCO), achieving excellent catalytic performance on refractory organic pollutant degradation via the synergistic effects between MnO and CN. The study demonstrated that the C–N−Mn and C−O−Mn bonds constructed in the catalyst linking MnO and CN created the synergistic effects which could overcome typical problems, such as metal leaching etc. The C−N−Mn and C−O−Mn bonds could promote electron transfer from cation-π reactions to form electron-rich Mn(II) sites and electron-poor CN sites. The electron-rich Mn(II) sites as active sites supplied electrons to ozone which then further evolved into reactive oxygen species (ROS). The electron-poor CN sites captured electrons from the pollutant intermediate radicals to electron-rich Mn(II) sites via cation-π reactions with the help of C−N−Mn and C−O−Mn bonds, which promote the redox reactions of Mn. The surface hydroxyl groups also participated in ozone decomposition and ROS production. Additionally, OH was the dominant ROS of the Mn- n CN HCO processes. This study presents the excellent HCO performance of Mn- n CN, as well as provides views on the electron transfer route between the catalyst, pollutant and ozone, which is crucial for the design of the catalyst. Graphical abstract: Image, graphical abstract