Bifunctional TiO2 (anatase, brookite, rutile)-based photocatalysis for environment remediation: Efficient simultaneous glyphosate degradation and H2 production

Glyphosate is currently the most widely used herbicide in the world due to its broad-spectrum effectiveness and relatively low cost. However, its massive and prolonged application has raised serious environmental concerns. In this context, novel strategies for the effective degradation of glyphosate and its derivatives are urgently needed. One promising and sustainable approach is the use of the photocatalytic method. In this study, we explore a polyfunctional photocatalytic system capable of producing high-value compounds by oxidation of glyphosate and simultaneously obtaining H2, a clean energy carrier. Namely, both organic and inorganic valuable compounds have been obtained by the partial oxidation of glyphosate. The effectiveness of various TiO2-based commercial and home-prepared polycrystalline photocatalysts has been explored. Pt-TiO2 and Cu2O-TiO2 heterostructured samples have been also investigated. The photocatalysts showed stability over repeated cycles and maintained their activity, indicating their practical potential. Mechanistic studies suggest that photogenerated holes were primarily responsible for the oxidative degradation of glyphosate, while photoexcited electrons drove the reduction of protons to H2 gas. Pt-Brookite, used for the first time in this reaction, resulted in the most active photocatalyst affording about 51% of glyphosate conversion and an H2 production of 0.34 mM.