A promising type-II/Z-scheme ternary MoS2/Bi2S3/Bi2WO6 heterostructure photoanode for photocatalytic fuel cell effective hydrogen production and electricity generation in organic wastewater

Developing efficient and stable bismuth-based photoelectrodes is one of the key points for producing green hydrogen in photocatalytic fuel cell (PFC). In this study, a PFC system with two photoelectrodes (a MoS 2 /Bi 2 S 3 /Bi 2 WO 6 photoanode and a MoS 2 -Ni foam photocathode) was established for the first time. The ternary Bi 2 WO 6 -based composite photoanode was characterized as having not only the broad visible absorption region but also strong interactions between Bi 2 WO 6 , Bi 2 S 3 and MoS 2 . Additionally, the ternary composite photoanode exhibits excellent photoelectrochemical performance, achieving a photocurrent density reaches 3.2 mA/cm 2 , which is 17.78 times that of pure Bi 2 WO 6 . These observations can be explained by the creation of a type II/Z-scheme heterostructure of MoS 2 /Bi 2 S 3 /Bi 2 WO 6 photoanode. The Density Functional Theory (DFT) simulation proves the formation of Z-scheme heterojunction between MoS 2 and Bi 2 S 3 , which offers an opportunity for facilitating the mitigation and separation of photoexcited charge. The dual-photoelectrode PFC system demonstrated an effective hydrogen production capacity, exhibiting an output of 18.32 μmol/cm 2 /h. At the same time, the power density was 0.1325 mW/cm 2 , exhibiting a 1.41-fold increase relative to the MoS 2 /Bi 2 S 3 /Bi 2 WO 6 -Pt PFC system. This work offers a novel method for building effective PFC systems that co-produce electricity and hydrogen.