Photogeneration of singlet oxygen catalyzed by hexafluoroisopropanol for selective degradation of dyes

Singlet oxygen (O-1(2)) shows great potential for selective degradation of dyes in environmental remediation of wastewater. In this study, we showcased that O-1(2) can be effectively generated from an anion complex composed of deprotonated hexafluoroisopropanol anion ([HFIP-H](-)) with hydroperoxyl radical (center dot HO2) via ultraviolet (UV) photodetachment. Electronic structure calculations and cryogenic negative ion photoelectron spectroscopy unveil critical proton transfer upon complex formation and electron ejection, effectively photoconverting prevalent triplet ground state O-3(2) to long-lived excited O-1(2), stabilized by nearby HFIP. Inspired by this spectroscopic study, a novel ''photogeneration'' strategy is proposed to produce O-1(2) with the incorporation of atmospheric O-2 and HFIP, acting as a catalyst. Conceptually, the designed catalytic cycle upon UV irradiation and electron injection is able to achieve different degradations of dye molecules in a controllable fashion from decolorization to complete mineralization, shedding new light on potential water purification.

Automated summary

Singlet oxygen (O-1(2)) has the potential for selective degradation of dyes in wastewater remediation, and it can be effectively generated through the reaction between an anion complex ([HFIP-H](-)) and hydroperoxyl radical (center dot HO2) through UV photodetachment. A novel "photogeneration" strategy is proposed to produce O-1(2) through the incorporation of atmospheric O-2 and HFIP, acting as a catalyst. This study sheds new light on potential water purification by achieving different degradation levels of dye molecules in a controllable fashion.