Hydrothermal synthesis of Fe3+–Bi2MoO6/Ppy heterojunction for enhanced the performance of catalytic reduction of Cr (VI)

The heavy metal Cr(VI) has caused serious impacts on human health and the ecological environment. To reduce the impact of Cr(VI), we prepared Fe³⁺-doped Bi₂MoO₆ using a hydrothermal method for the reduction of Cr(VI) to Cr(III). The effect of Fe doping on the structure, morphology, and properties of Bi₂MoO₆, and obtained the optimal doping amount of Fe³⁺. Fe ions doping can significantly reduce the bandgap, resulting in good visible-light absorption intensity and significantly expand the light absorption range. Fe–Bi₂MoO₆/Ppy heterojunctions were prepared by in situ polymerization deposition methods to improve their photo-reduction performance. During the reduction, the reduction rate of single Bi₂MoO₆ is 29.4%. When the Fe³⁺ doping amount is 1.0 wt%, the Cr(VI) reduction rate of 1.0Fe-Bi₂MoO₆ material is 33.6%, and the reduction efficiency is slightly improved. The Cr(VI) reduction rate of the 1.0Fe-Bi₂MoO₆/0.5Ppy composite photo-catalyst reached 92.5%, significantly improving the Cr(VI) reduction effect. Its corresponding reduction rate is 7.24 times that of Bi₂MoO₆ and 11.74 times that of Ppy. This work indicated that the construction of 1.0Fe–Bi₂MoO₆/0.5Ppy heterojunction is an effective approach to improve photocatalytic activity of Bi₂MoO₆ and efficiently reduce Cr(VI).