Cooperative photocatalysis of dye-Ti-MCM-41 with trimethylamine for selective aerobic oxidation of sulfides illuminated by blue light

Ti-incorporated mesoporous materials have widespread applications in photocatalysis. Their adjustable pores could accommodate dyes like alizarin red S (ARS) to circumvent the lack of visible light response. Herein, Ti-MCM-41 was obtained to anchor visible light-capturing ARS, forming ARS-Ti-MCM-41. The ARS-Ti-MCM-41 was screened for the selective photocatalytic oxidation of organic sulfides. To improve the stability of the anchored ARS, electron transfer was orchestrated by a mediator trimethylamine (TMA, 2 mol%) illuminated by blue LEDs. Phenyl methyl sulfide could be almost entirely converted into phenyl methyl sulfoxide with 99% of selectivity within 18 min. In addition, Ti-MCM-41 was beneficial for the anchored ARS, which in turn guaranteed good recycling performance of ARS-Ti-MCM-41. The solvent tri-fluoroethanol enabled the stability of TMA and facilitated the highly selective formation of the target sul-foxides. This work sheds light on the vast possibility for visible light photocatalysis of dye-mesoporous materials.(c) 2022 Elsevier Inc. All rights reserved.

Automated summary

Ti-incorporated mesoporous materials, such as Ti-MCM-41, have been used to anchor visible light-capturing dyes like ARS for selective photocatalytic oxidation of organic sulfides. This study demonstrated that electron transfer mediated by TMA improved the stability of ARS and resulted in highly selective formation of sulfoxide products. The use of trifluoroethanol solvent facilitated the stability of TMA and enhanced the selectivity of the target products.