In-situ fabrication of a phase continuous transition Bismuth iodide/Bismuth niobate heterojunction: Interface regulation and the enhanced photodegradation mechanism.

[Display omitted] • A Z-scheme Bismuth iodide/Bismuth niobate heterojunction was synthesized. • Photodegradation activity was rely on the interface structure of the photocatalyst. • Interface was continuously transitional with a proper molar ratio of the Nb and Bi. • DFT analysis and the Fukui index was used to explore the degradation pathway. A direct Z-scheme bismuth iodide/bismuth niobate (BiOI/BiNbO) heterojunction photocatalysts with a different molar ratio of Bi/Nb were prepared. The structural and photoelectrical properties of these as-prepared samples were investigated, photocatalytic activity and different effect factors were evaluated. The experiment results indicated that the highest RhB degradation efficiency was that of the sample with Bi/Nb = 0.7, bringing a lower interface resistance that facilitate the separation and transportation of photogenerated carrier. Furthermore, active species trapping experiments suggested that •OH was the most contributor responsible for the RhB photocatalytic process. The photodegradation mechanism and a reasonable degradation pathway were further proposed by DFT theoretical calculation. [ABSTRACT FROM AUTHOR]