Substituent-induced oxidation-reduction molecular organic junction for interfacial hydrogen peroxide photosynthesis

Abstract

Abstract The distribution of catalytic active sites critically dictates photocatalytic efficiency, but existing catalyst design operate at the same or adjacent sites still remain limitations toward photocatalytic reaction. To address this, a kind of spatially separable oxidation-reduction assignment in fluorine substituted molecular organic junction catalyst (covalent triazine framework, CTF-TF-0.5) is constructed. By modulating the coordination of F-substituted benzene linkers, we controlled the redox nature of triazine ring in CTFs to obtain the separable oxidation-reduction assignment. It achieves a interfacial hydrogen peroxide (H 2 O 2 ) photosynthesis rate of 4664 µmol g −1 h −1 at triphasic interface with simulated sunlight and ultrasonic forces. With external forces, the photogenerated-holes allow to transfer to the oxidation site (triazine connected two benzene and a F-substituted benzene) and photogenerated-electrons to the reduction site (triazine connected a benzene and two F-substituted benzene) via benzene bridges for a dual-pathway of water oxidation and oxygen reduction reactions to synthesize H 2 O 2 . Additionally, this heterogeneous interfacial reaction system exhibits efficient purification capability for arsenic-containing mining wastewater. This study using the separable oxidation-reduction sites for addressing the coupling reaction at manipulable active sites to improve overall catalytic efficiency via molecular junction catalyst.