A recent overview of photo electro catalytic materials mechanistic insights towards PFASs degradation: By-products determination and AI/ML implications.

Around 10000 compounds of Poly-and perfluoroalkyl substances (PFASs) exposure is ill-affecting the environmental resources (Direct healthcare expenditures ∼ USD 100 billion). This review details electrochemical and photo-catalytic activities of various materials/composites towards PFASs degradation. The technical observations in the current work are majorly referenced from recent literature published in the last five years (2020-2025). The iron and titanium species have shown better remediation abilities which reported with majority of publications. Iron systems have shown better parameters for electrochemical activities (electro oxidation/reduction) whereas titanium sub oxides and bismuth sheets are better related to the photo electrochemical activity. Other 3d-metal systems like Co, Ni, and boron doped diamond, carbon structures (activated carbon, carbon sphere and aerogel) are also detailed with PFOA and PFOS treatment. In understanding the degradation mechanism, the radical species activity has densely dominated the process with the support of radical oxygen/sulphur species and charge transfers. Radical species activity, dissolved oxygen influence, and direct electron transfer (DET) mechanism are provided in understanding the heterogeneous catalytic reactions and redox materials chemistry. Decarboxylation (DHEH), and hydro-defluorination (HDF) mechanisms are explained with a set of findings based on catalyst and chain length of compound (Long/Short-chain). Determination of degradation byproducts and intermediates utilizing different state-of-the-art spectroscopy tools (LC-MS, GC-MS) are detailed in supporting the issue related to the secondary contamination in various remediation sites and necessary field studies findings (e.g., Landfills, WWTP). Implications of AI/ML towards efficient handling of the various PFASs treatment and management technologies are discussed briefly.