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使用溶胶-凝胶法制备了α-Fe2O3薄膜,研究了氢氟酸腐蚀薄膜表面对其光电化学性质的影响.实验发现,薄膜表面的孔洞和间隙随着氢氟酸浸蚀时间的增长而发生变化.氢氟酸浸蚀5 min,α-Fe2O3电极的光电流降低;随后随浸蚀时间增加而迅速增加;当浸蚀时间大于15 min时,其光电流再次下降,但对浸蚀过的样品再次退火可以使光电流大幅增加.通过电化学交流阻抗谱、拉曼和X射线光电子能谱分析,提出了两个影响光电流的因素:氢氟酸表面浸蚀造成薄膜表面的多孔性和结晶度降低.为此,通过示意图解释了结合浸蚀和退火后处理两个步骤来增强α-Fe2O3薄膜光解水电极光电活性的原理.相对于初始的α-Fe2O3电极,浸蚀并且再退火处理后,其光电性质更加稳定.
The α-Fe2O3 thin films were prepared by sol-gel method and the effects of hydrofluoric acid etching on the photoelectrochemical properties of the films were investigated. It was found that the pores and gaps on the surface of the films changed with the increase of hydrofluoric acid etching time The photocurrent of α-Fe2O3 electrode decreased after 5 minutes hydrofluoric acid etching, then increased rapidly with the increase of etching time. When the etching time was longer than 15 minutes, the photocurrent decreased again. However, The sample annealed again can increase the photocurrent greatly.According to electrochemical impedance spectroscopy, Raman and X-ray photoelectron spectroscopy analysis, two factors affecting the photocurrent were proposed: the hydrofluoric acid surface etching caused the film surface porosity and The degree of crystallinity is reduced.Therefore, the principle of enhancing the electro-optical activity of a-Fe2O3 thin film photolysis water electrode by combining the two steps of etching and post-annealing treatment is illustrated by the schematic diagram, etching and re-annealing relative to the initial α-Fe2O3 electrode After treatment, its photoelectric properties are more stable.