Preparation and photoelectrochemical properties of WO₃/Bi₂MoO₆ composite films

The application of WO₃ materials has been attracted much attention in photoelectric catalysis, but its poor photo-generated electron hole separation ability and low utilization rate of sunlight have limited its photoelectric catalytic property. To solve this problem, WO₃ nano-films were prepared on the conductive glass (FTO) by hydrothermal method, and WO₃/Bi₂MoO₆ composite films with different reaction time (7 h, 9 h and 11 h) were synthesized on WO₃ nano-films by solvothermal method. XRD and SEM tests proved the successful preparation of WO₃/Bi₂MoO₆ composite films. The WO₃/Bi₂MoO₆ composite film samples were subjected to absorption spectrum test, photocurrent test, photoelectric catalytic test and alternating current impedance test. The results show that the WO₃/Bi₂MoO₆ composite film samples have better light absorption characteristics, more outstanding photocurrent characteristics and significantly improved photoelectrocatalysis activity compared with pure WO₃ nano-films. And the WO₃/Bi₂MoO₆ composite film samples with the hydrothermal reaction for 9 h have the highest photocurrent density and the best photoelectrocatalysis efficiency. The analysis suggests that the WO₃/Bi₂MoO₆ composite film may constitute a heterojunction structure, which reduces the electronic impedance inside the composite film and increases the effective photoelectrochemical reaction sites; Meanwhile, the response range of the spectrum is expanded by increasing the utilization rate of sunlight. So the photoelectrochemical property can be significantly improved.