Controlled synthesis and exceptional photoelectrocatalytic properties of Bi2S3/MoS2/Bi2MoO6 ternary hetero-structured porous film.

In this work, Bi2S3/MoS2/Bi2MoO6 hetero-structured porous films were fabricated via a facile anion exchange process using the as-prepared Bi2MoO6 nanoflake array film as substrate material. The formation of Bi2S3/MoS2/Bi2MoO6 ternary hetero-structured porous film is both thermodynamically controllable and reaction time dependent. Systematic experiments were done to investigate the products at each reaction stage and disclose the relationships between the composite components and reaction temperature and time. The study showed that the energy barrier need to be overpassed when MoS2 and Bi2S3 were simultaneously produced. The optimized Bi2S3/MoS2/Bi2MoO6 photoelectrode exhibited significantly higher photoelectrocatalytic efficiency than Bi2MoO6, binary Bi2S3/Bi2MoO6 and Bi2S3/MoS2 photoelectrodes. The remarkable degradation efficiency of the Bi2S3/MoS2/Bi2MoO6 photoelectrode comes from the synergy of high quality assembly and heterostructure interfaces between the three components. The optimized film assembly and stepwise band alignment in the ternary heterostructure composite contribute to visible light utilization, transport and separation of charge carriers, mass transport, and accessibility of active sites. The generated active species such as superoxide anions (O2-) and holes were detected to promote the decomposition of organic pollutants. The reasonable photoeletrocatalytic degradation mechanism was also proposed.