关键词: &alpha, -Fe₂O₃；Sn掺杂；氧空位；表面反应速率

Abstract:

The α-Fe₂O₃ nanoparticles containing oxygen vacancies were synthesized in atmospheric N₂ by dip-dropping method without a high vacuum employed before annealing. The influences of annealing atmosphere and Sn-doping on the photocatalytic performance of α-Fe₂O₃ nanoparticles were studied by annealing the photocatalyst in N₂ or air and adding SnCl₄ to the precursor directly. The results showed that the current density of Sn-doping α-Fe₂O₃ annealed in N₂ at 550 °C and 1.23 V (vs. RHE) was 35 times greater than that of pristine α-Fe₂O₃ annealed in N₂ at 550 °C and 15 times greater than that of Sn-doping α-Fe₂O₃ annealed in air at 550 °C, which indicated that both Sn-doping and annealing in N₂ were indispensible to obtain a good performance for α-Fe₂O₃ nanoparticles. Mott-Schottky curves and electrochemical impedance spectroscopic data proved that both Sn-doping and oxygen vacancy could lead to the increase of the donors concentration and conductivity, which resulted in the enhanced performance of α-Fe₂O₃ nanoparticles. The photocatalytic performance tested in the electrolyte containing sacrifice solvent confirmed that the Sn-doping could facilitate the surface reaction, which was another key factor contributed to the enhanced performance of α-Fe₂O₃ nanoparticles.

Key words: α-Fe₂O₃ photocatalyst, oxygen vacancy, Sn doping, surface reaction rate