Preparation And Performance Study Of Novel Ta/Al-Fe₂O₃, Fe₂O₃-FeOOH-NiOOH And Fe₂O₃-MoS₂ Thin Films

Photoelectrochemical (PEC) technology is a kind of green, clean and sustainable new technology since it can both utilize solar energy for efficiently degradation of organic pollutants and simultaneously conduct photoelectrochemical water splitting into hydrogen. The efficient and stable catalysts which can utilize visible light play a key role in PEC process.A nanorod structure of Ta/Al-Fe2O3 film was triumphantly synthesized by facile electrodeposition and drop coating method. The EDX pattern showed that Tantalum and aluminum were sucessfully co-doped into Fe2O3. The composite films shown more efficient separation and easier transfer of photogenerated electron-hole pairs. Furthermore, the Ta/Al-Fe2O3 film exhibited higher efficiency in the simultaneous reduction of Cr(Ⅵ) and oxidation of phenol solution than film under visible light irradiation. The PEC reaction rate of Cr(Ⅵ) and phenol of Ta/Al-Fe2O3 film was 2 times and 1.3 times higher than that of the pure Fe2O3 film, respectively. The best degradation efficiency can be achieved in the appropriate condition of the pH, the applied voltage and the initial concentration of Cr(VI) and phenol. Ta/Al-Fe2O3 films displayed the excellently enhanced PEC activity and stability.The composite Fe2O3-FeOOH-NiOOH was prepared by simple electrodeposition and cyclic voltammetry method, which exhibit higher activity of water splitting into oxygen and better stability. The photocurrent density of Fe2O3-FeOOH-NiOOH film in NaOH solution under visble light irradiation presented 70 times higher than pure Fe2O3 film under the condition of 0.60 V vs. Ag/AgCl. The analyses of surface characterization and PEC properties indicated that FeOOH and NiOOH were sucessfully co-doped with Fe2O3 film. The composite Fe2O3-FeOOH-NiOOH film under PEC degradation of phenol showed significantly higher efficiency than that under pure photocatalytic or electrocatalytic effect. Moreover, the phenol degradation efficiency of the composite film was about 2 times higher than that of pure Fe2O3 film. After 4 times recycle experiments of phenol degradation, it also showed that the composite film had good stability and better reusability.Fe2O3-MoS2 composite film was synthesized through the two-step electrodeposition method. PEC activity of the Fe203-MoS2 composite film was greatly increased due to MoS2 doping. The as-prepared film can significantly hinder the recombination of generate electron and hole by Fe2O3 itself produced under light irradiation. The photocurrent density of Fe2O3-MoS2 film exhibited 78 times higher than pure Fe2O3 film at 0.60 V vs. Ag/AgCl under light irradiation. The H2 evolution reaction on Fe2O3-MoS2 film was conducted more easily than that on Fe2O3 film. The composite film presented excellent photostability by FeOOH and NiOOH doping. Moreover, the PEC reaction rate of phenol of Fe2O3-MoS2 film was 2 times and 3 times higher than that of the single PC or EC, respectively. The main degradation intermediate were benzoquinone and hydroquinone during phenol degradation process. In addition, the possible mechanism of PEC reactions about phenol was proposed.