Novel CoFe2O4/Bi2WO6 S-scheme heterostructure photocatalyst for effective and rapid visible-light-driven reduction of toxic nitrobenzene into industrially valuable aniline

Abstract

Photocatalytic transformation of toxic nitrobenzene (NB) into highly industrially valuable aniline (AN) has emerged as a promising and prospective strategy. In this work, mesoporous S-scheme CoFe2O4/Bi2WO6 (CFO/BWO) heterostructure photocatalysts were constructed using a simple surfactant-aided sol–gel technique for visible-light-induced reduction of NB into AN. The characterization findings demonstrated the successful loading of p-type CFO nanoparticles (NPs) on a 2D n-type BWO framework, forming a p-n heterostructure. The as-synthesized heterostructure exhibited enhanced visible light absorbance, with superior photosensitivity up to 564.43 nm, which surpassed the optical absorbance of bare BWO by ∼ 1.26 times. In addition, PL and photoelectrical measurements demonstrated significantly enhanced separation and kinetics for light-generated charge carriers for the constructed CFO/BWO heterostructures compared to bare specimens. Therefore, the CFO/BWO heterostructure photocatalysts exhibited superior efficacy compared to pristine CFO and BWO. The NB was reduced into AN with a conversion efficacy of 100.0 % within 40.0 min on the 12.0 % CFO/BWO with a reaction rate constant of ca. 0.07616 min−1, which outperformed the pure CFO and BWO by more than 3.5- and 4.2-folds, separately. This optimized heterojunction exhibited excellent repeatability (98 %) during five cycles. This superb photocatalytic effectiveness can be pinned to the effective growth of the S-scheme heterostructure between CFO and BWO, substantially accelerating the transmission of carriers and their spatial separation by forming an inherent electric field and band curving at the interface. Our contribution offers novel and distinct hot points for the design of scalable and highly effective S-scheme heterostructures for multiple promising photocatalytic purposes.