CuWO4|MnWO4 heterojunction thin film with improved photoelectrochemical and photocatalytic properties using simulated solar irradiation.

In this paper, we report the synthesis of CuWO₄, MnWO₄, and FTO|CuWO₄|MnWO₄ as type II heterojunction thin film prepared by the drop-casting method. These thin films were synthesized by microwave-hydrothermal method with pure phase formation confirmed by X-ray diffraction (XRD), micro-Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analyses. The photoelectrochemical response of these films was investigated under simulated illumination with AM 1.5 G type filter. The heterojunction displayed photocurrent density values two times higher than the FTO|CuWO₄ film, reaching 39 μA/cm² at 1.23 V versus normal hydrogen electrode. Optical and electrochemical characterizations revealed superior visible light absorption and lower charge transfer resistance for the FTO|CuWO₄|MnWO₄ heterojunction thin film. Low photoluminescence emission and transient photocurrent data confirmed a decreased electronic charge transfer between the valence and the conduction band, besides a reduced electron–hole recombination rate for the FTO|CuWO₄|MnWO₄ heterojunction film. Mott-Schottky photocurrent response investigation revealed that the FTO|CuWO₄|MnWO₄ heterojunction thin film can be considered an excellent photoanode for photoelectrocatalytic applications under solar irradiation. Finally, the heterojunction exhibited better performance for the photodegradation of Rhodamine B (RhB), corresponding to 55.5% at 165 min. [ABSTRACT FROM AUTHOR]