| 초록 |
The bismuth vanadate (BiVO4) is one of the most promising photoanode materials. It has narrow band gap (2.4eV) and suitable band edge position for oxygen evolution reaction (OER) which is important for photoelectrochemical (PEC) water splitting. However, the actual conversion efficiency of BiVO4 photoanodes is lower than theoretical value of that, due to several drawbacks such as charge carrier recombination, poor charge transport, and sluggish OER kinetics. Thus, it is important to form the heterojunction with another materials which can overcome these drawbacks to improve the photoactivities of BiVO4 photoanodes. Herein, we report the novel technology for electrochemical synthesis of BiVO4/MeOx heterogeneous photoanodes and its improved photoactivities. Compared to vacuum process, pulsed electrodeposition is not only fast and cheap process, but also feasible to control morphology of the metal oxide materials. We show that BiVO4/MeOx photoanodes enhance the charge separation efficiency by forming TypeⅡ band alignment. Finally, we report enhanced PEC performances of BiVO4/MeOx including current density-voltage curves (J-V) and incident-photon-to-current efficiency (IPCE). This work reveals relationship between the change of band structures caused by heterogeneous metal oxide and photoactivities of BiVO4 photoanode from the combined spectroscopic analysis and photoelectrochemical measurement, and provides applicability to various photoelectrode systems. |
