BiOCl/TiO2 heterojunction network with high energy facet exposed for highly efficient photocatalytic degradation of benzene

Abstract

Benzene is known for its difficulty of degradation as well as enormous harmful intermediates released during degradation, which arouses urgent demand for highly efficient photocatalysts as solution. In this paper, we fabricated a 3D hierarchical structure of 2D single crystalline BiOCl nanosheets with high energy (001) facets exposed using 1D single-crystalline TiO2 nanorod array as supporting framework and charge transfer tunnel. Compared to releasing various intermediates by the TiO2 nanorod array during photocatalysis, the BiOCl/TiO2 heterojunction network exhibited phenomenal photocatalytic activity for fully degradation of 150ppm gaseous benzene within 80min, yielding stoichiometric 900ppm CO2 with excellent repeat stability. The outstanding photocatalytic performance is ascribed to the charge separation across the BiOCl/TiO2 interface, which is evidenced by density functional theory (DFT) based calculation as well as photoluminescence and photocurrent experiments. Furthermore, the internal electric fields of BiOCl and TiO2 nanorod high-speed transferring tunnel also make contributes to the charge separation. Then the reserved holes at (001) facets of BiOCl, which is believed to be the major actives for gaseous photocatalysis, can migrate to the surface oxygen vacancies for decomposing benzene with oxygen molecules. In addition, the scavenging effect due to oxygen vacancies on (001) facet of BiOCl is also responsible for the excellent and sustainable photocatalytic activity. This work reveals an approach for novel photocatalysts by building band-aligned 3D heterojunction network with high energy facet exposed as active sites.