Hybridizing Engineering Strategy of Decatungstate. 2. Regulated Effect of Doping Transition Metal Ions on Photocatalytic Oxidation Performance of (nBu4N)4W10O32.

Abstract

This paper discloses a simple and productive hybridizing engineering (HE) strategy for the 3d transition-metal-ion (Mn+ = Fe3+, Fe2+, Co2+, Ni2+)-doped (nBu4N)4W10O32 (Mn+-TBADT) compounds as highly efficient visible-light catalysts. Ultraviolet visible (UV-vis), Fourier transform infrared (FT-IR) and photoluminescence (PL) spectra, and cyclic voltammetry (CV) characterizations indicate that the synthetic quality, redox capacity, and visible light harvesting efficiency of TBADT, especially the separation efficiency of its photogenerated electron-hole pairs, are regulated by the metal ion dopants and gradually improved with a change of the dopant from Fe3+, Fe2+, and Co2+ to Ni2+, along with a continuous and significant enhancement of its photocatalytic efficiency in the visible-light-triggered selective oxidation of ethylbenzene with dioxygens in acetonitrile. The best 0.5 mol % Ni2+-doped TBADT can achieve a ca. 55% conversion under optimal reaction conditions and also exhibits much higher photocatalytic activity for the photo-oxidation of toluene, cyclohexane, and benzyl alcohol compared to pure TBADT. This HE strategy showcases great potential in improving the photocatalysis performance of TBADT.