A simple method for fabricating p–n junction photocatalyst CuFe2O4/Bi4Ti3O12 and its photocatalytic activity

Abstract

The synthesis of Bi4Ti3O12 and CuFe2O4 powders was achieved using a conventional solid-state reaction and the Sol–Gel method, respectively. A novel p–n heterojunction photocatalyst CuFe2O4/Bi4Ti3O12 was subsequently prepared through ball milling. The structures, morphologies, and optical properties of the photocatalysts were comprehensively characterized. The transmission electron microscopy (TEM) images showed a clear interface between CuFe2O4 and Bi4Ti3O12, indicating that a heterojunction between CuFe2O4 and Bi4Ti3O12 was formed during ball milling. In addition, the photocatalytic activity was evaluated based on the photocatalytic degradation of methyl orange (MO). The results indicated that the photocatalytic activity of the p–n heterojunction photocatalyst CuFe2O4/Bi4Ti3O12 was higher than that of Bi4Ti3O12 alone. The enhanced photocatalytic activity could be attributed to the formation of a heterojunction between CuFe2O4 and Bi4Ti3O12, which suppressed the recombination of photogenerated electron–hole pairs. We also investigated the effects of procedure time and dispersant (H2O) during ball milling on the photocatalytic activity. The mechanisms underlying the observed photocatalytic activity were also described based on the semiconductor energy band theory and p–n junction principle. Moreover, the analysis of the radical scavengers confirmed that •O2− and h+ were the primary reactive species to cause the degradation of the MO.