Multipath collaboration mechanisms involved in the photocatalytic reduction of Cr(VI) by FeC2O4/Bi2.15WO6.

[Display omitted] • FeC 2 O 4 enhanced the separation of photogenerated e- and h+ in the system of FeC 2 O 4 /Bi 2.15 WO 6. • The reduction rate of Cr(VI) in the system of FeC 2 O 4 /Bi 2.15 WO 6 increased by 33.3 times. • Multipath collaboration mechanism enhanced the reduction of Cr(VI) by FeC 2 O 4 /Bi 2.15 WO 6. FeC 2 O 4 /Bi 2.15 WO 6 (FeC 2 O 4 /BWO) composites were prepared, and the mechanism involved in the photocatalytic reduction of Cr(VI) by FeC 2 O 4 /BWO was investigated. When the doping amount of FeC 2 O 4 was 10%, the obtained 10-FeC 2 O 4 /BWO composite exhibited the best Cr(VI) reduction activity with a rate constant of 0.1934 min−1, which was 33.3 times higher than that of BWO. The improved photocatalytic performance of 10-FeC 2 O 4 /BWO was ascribed to the efficient carrier separation, which was confirmed by the higher transient photocurrent and lower PL intensity than single BWO. Capture experiments further revealed that photogenerated electrons were the major species for reducing Cr(VI) by 10-FeC 2 O 4 /BWO. Dissolved Fe(II) (Fe(II) diss) released from the surface of FeC 2 O 4 can reduce Cr(VI) to Cr(III) directly, along with the formation of Fe(III) diss. Meanwhile, the potential difference between BWO and FeC 2 O 4 can form a built-in electric field. This field facilitates the movement of photogenerated electrons, leading to the conversion of Fe(III) diss to Fe(II) diss , could transform and drive the circulation of 'Fe(II) diss -Fe(III) diss -Fe(II) diss '. Furthermore, the electrons transferred to the conduction band (CB) of BWO enhance the reduction of Cr(VI). The above multipath collaboration mechanism enhanced the reduction of Cr(VI) by 10-FeC 2 O 4 /BWO. Therefore, this study provides data basis and theoretical support for remove Cr(VI) and other pollutants. [ABSTRACT FROM AUTHOR]