| 초록 |
Heterojunctioned composite semiconductors are an efficient system for electron-hole separation to minimize the energy wasteful electron-hole recombination. In this work we introduce a kind of heterojunctioned composite electrodes for photoelectrochemical (PEC) cell application for enhancement of WO3 efficiency. We have prepared WO3 and BiVO4 composite electrode by polymer-assisted deposition. All samples consisted of each layer of WO3 and BiVO4 and has thickness around 2~2.5μm. They were calcined at 550oC under air atmosphere. The prepared films were characterized using XRD, SEM, UV-Vis spectra and electrochemical analysis.The photocurrents were measured under AM 1.5G simulated solar light in 0.5M Na2SO4. In the IPCE data, WO3 absorbed the light of 500nm due to band gap of 2.7eV. Thus, the onset of IPCE started at 500nm for WO3 electrode. The BiVO4 could absorb more light of longer wavelengths than WO3 due to band gap of 2.5eV, so that BiVO4 showed photoactivity at 540nm. Yet, its photoactivity for O2 generation was much lower than that from WO3. The WO3-BiVO4 composite electrode show a synergism showing higher activity than WO3 and BiVO4 combined. |
