• Surface-centered photocatalysis emerged as a dominant paradigm, highlighting oxide substrates (TiO2) and nanostructured metal deposition as active mediators. Studies trace noble-metal deposition on TiO2, heterogeneous cyanide oxidation on TiO2 powder, TiO2-based water electrolysis, and solvent/surface effects that tune dye-sensitized oxidation pathways [3], [4], [7], [11], [12].

• Photosensitized oxidation driven by dyes such as eosin and methylene blue, with solvent and ambient environment modulating mechanisms and efficiencies. The corpus includes eosin-driven iodide and amino-acid oxidation, methylene blue–assisted amino acid oxidation, dye-sensitized photooxygenation, and related dye photochemistry [2], [8], [9], [15].

• Polymer photodegradation and environmental photochemistry reveal pathways for polymer chain scission and surface changes under irradiation, informing material lifetimes and degradation products. Key examples include photochemical degradation of PET, and polymer oxidation in polymer I and II studies [6], [10], [13].

• Foundational photochemical mechanisms and primary processes underpinning broader photocatalysis: photoionization of alkanes, photochemical enolization of o-substituted benzophenones, unusual photochemical rearrangements, and photosynthesis photochemical systems [16], [17], [19], [20].

• Photoregulation and enzymatic photochemistry reveal early integration of light control in biocatalysis, with light-sensitive ligands modulating enzymatic activity and photophosphorylation, and ATP hydrolysis potentiation under illumination [5], [14], [18].