Two-dimensional layered carbon-based catalytic ozonation for water purification: Rational design of catalysts and an in-depth understanding of the interfacial reaction mechanism

This review renewed insight into the existing complex and contradictory mechanisms of catalytic ozonation by twodimensional layered carbon-based materials (2D-LCMs) for degradation toxic refractory organics in aqueous solution. Migration and capture of active electrons are central to catalytic ozonation reactions, which was not studied or reviewed more clearly. Based on this perspective, the catalytic ozonation potential of 2D-LCMs synthesized by numerous methods is firstly contrasted to guide the design of subsequent carbon based-catalysts, and not limited to 2D-LCMs. Matching ROS to active sites is a key step in understanding the catalytic mechanism. The structure-activity relationships between reported numerous active sites and ROS evolution is then constructed. Result showed that center dot OH could be produced by-OH,-C=O,-COOH groups, defective sites, immobilized metal atoms, doped heteroatoms and photo-induced electrons; and center dot O-2- could be produced by-OH groups and sp2-bonded carbon. The normalized model further be used to visually compare the contribution degree of various regulatory methods to performance improvement. More importantly, this review calls for 2D-LCMs-based catalytic ozonation to be studied without circumventing the issue of structural stability, which would lead to many proposals of catalysts and its involved catalytic reactionmechanism being meaningless.

Automated summary

This review provides detailed insights into the mechanisms of catalytic ozonation by two-dimensional layered carbon-based materials (2D-LCMs) for degrading toxic refractory organics in aqueous solutions. It emphasizes the importance of the migration and capture of active electrons in catalytic ozonation reactions and discusses the structure-activity relationships between various active sites and the evolution of reactive oxygen species (ROS). The review also highlights the significance of studying the structural stability of 2D-LCMs-based catalytic ozonation and calls for further research in this area.