Photocatalytic degradation of microplastics: From efficiency assessment to rational system design

The photocatalytic degradation of microplastics (MPs) lacks standardized analytical workflows. This gap severely hinders the comparison of studies and the interpretation of degradation mechanisms. The current literature is fragmented, as results depend on a complex mix of reaction conditions, material properties, and the intrinsic limitations of the analytical techniques themselves. This review introduces the first analytically driven framework to rationalize experimental design in this field. We systematically deconstruct the process into critical factor groups: environmental/operational parameters, photocatalyst properties, polymer characteristics and surface interaction and pretreatment. Crucially, we map how these factors directly impact the choice, applicability, and reliability of key analytical techniques, such as microscopic, spectroscopic, chromatographic, and thermal analyses. Thus, the proposed framework provides a clear roadmap for designing more rigorous and comparable studies on the photocatalytic degradation of MPs. It addresses a critical methodological gap, facilitating clearer insights into degradation features.