Plasma-Activated Homogeneous Catalysis for Water Decontamination: Mechanisms, Synergies, and Future Perspectives

The pervasive contamination of water bodies by refractory organic pollutants necessitates the development of advanced purification technologies. Plasma has emerged as a promising solution, capable of generating a broad spectrum of reactive oxygen and nitrogen species (RONS), UV photons, and electrons in situ, thereby directly degrading contaminants. However, the practical application of plasma-alone systems is often constrained by limited energy efficiency and insufficient mineralization capacity. To overcome these challenges, the integration of plasma with homogeneous advanced oxidation processes (AOPs) has been established as a highly effective strategy. By coupling plasma with catalysts such as peroxymonosulfate (PMS), peracetic acid (PAA), periodate (PI), and Fenton reagents (Fe2+/Fe3+), a remarkable synergistic effect is achieved. This synergy arises from the multi-modal activation of catalysts by plasma via energetic electrons, UV photolysis, and radical-induced reactions, while the catalysts, in turn, consume long-lived plasma products and regulate reaction pathways. The resultant ‘plasma/catalytic’ system significantly enhances the degradation rate and mineralization efficiency of pollutants, broadens the operational pH window, and improves overall energy utilization. This review systematically examines the mechanisms, performance, and influencing factors of these hybrid systems, and discusses current challenges and future prospects to guide the development of this synergistic technology for sustainable water remediation.