A sillenite-type Bi12MnO20 photocatalyst: UV, visible and infrared lights responsive photocatalytic properties induced by the hybridization of Mn 3d and O 2p orbitals

5 years ago

A sillenite-type Bi12MnO20 photocatalyst: UV, visible and infrared lights responsive photocatalytic properties induced by the hybridization of Mn 3d and O 2p orbitals

Although UV and visible lights induced photocatalysis has been well developed in recent years, the full spectrum of UV, visible and NIR lights responsive photocatalysis is still few, which is beneficial for energy utilization and practical application. Herein, we report a new sillenite-type Bi12MnO20 photocatalyst prepared by a facile sol-gel method. Through incorporating the Mn⁴⁺ ions into tetrahedral sites of metastable cubic γ-Bi2O3 to split the 3d orbits of Mn⁴⁺, the new-produced Bi12MnO20 crystal presents peculiar and strong absorption capability, covering the full spectrum of UV, visible and NIR lights in the range of 200–1300nm. The DFT calculation further confirms the existence of intermediate band state in the band gap of Bi12MnO20, which was formed by the hybrid of O 2p and Mn 3d orbits. More importantly, under the irradiation of UV, visible and NIR lights, Bi12MnO20 product exhibits excellent photocatalytic reduction activity for Cr(VI), which is mainly due to the relatively good charge separation enhanced by unique electronic structure of the Bi³⁺ 6s² lone pair, the suitable band positions and the introduction of intermediate band state. In addition, the Bi12MnO20 specimen also displays good visible light driven photocatalytic oxidation property for acid red G, which is mainly caused by h⁺ and O2 ⁻ species. The as-prepared Bi12MnO20 semiconductor would provide a new potential to fulfill the full spectrum responsive photocatalysis.

Publisher URL: www.sciencedirect.com/science

DOI: S0926337317306653