PVA(Polyvincyl Acohol)-assisted Hydrothermal Preparation of Bi 25 FeO 40 and Its Photocatalytic Activity
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1217-Y03-22
PVA(Polyvincyl Acohol)-assisted Hydrothermal Preparation of Bi25FeO40 and its Photocatalytic Activity Jianmin Li,Juyue Song,Jianguo Chen,Shengwen Yu ,Dengren Jin and Jinrong Cheng School of Material Science and Engineering,Shanghai University,Shanghai,China ABSTRACT A PVA-assisted hydrothermal synthesis route was utilized to fabricate single-phase Bi25FeO40 crystallites.X-ray diffraction results indicated that sillenite Bi25FeO40 have been synthesized at the temperature of 200 ℃ using the KOH concentration of 7 M. Scanning electron microscopy showed the morphology of the as-prepared products were cubic shape with side length of 26 µm. The band gap of Bi25FeO40 was determined to be 1.8 eV (688 nm) by using UV-vis diffuse reflectance spectroscopy. It was found that Bi25FeO40 exhibited a high photocatalytic activity for the degradation of methyl orange under UV-Vis irradiation, being a potential material for photocatalytic decomposition of organic contaminants. INTRODUCTION Semiconductor photocatalysis has been shown to be a promising technology for the removal of toxic organic contaminants from water[1]. To date, most investigations have focused on the photocatalyst TiO2 because of its high activity and chemical stability. However, TiO2 is only able to optically respond to ultraviolet irradiation (< 387 nm) owing to its wide bandgap (Eg = 3.2 eV)[2].Therefore, it is of great scientific and technological interest to develop new photocatalysts that has photocatalytic activities under visible light. The sillenites, with the general formula Bi12MO20 (M=Ge, Ti, Ga, Fe, Bi, V, etc.), exhibit various properties such as photorefractivity, optical activity and photo-conductivity[3,4]. Recently, sillenite compounds as a kind of novel photocatalysts with a high photocatalytic activity, have been receiving more and more attention[5]. So far, sillenites such as Bi12TiO20[6], Bi24Ga2O39[7], Bi24AlO39 [8] and Bi12SiO20[9] have been reported the high photocatalytic property owing to the Bi-O polyhedra in Bi12MO20 crystals.It is repoted that the BiO7 polyhedron results in a dipole moment of 0.174 Debye,which were assumed to eliminate the recombination of electron–hole pairs and significantly facilitate the photocatalytic activity of the catalysts [7,10]. Bi25FeO40 crystals have been attracted attention because of its optical property[11]. Bi25FeO40,as a kind of sillenite compounds, however, as far as we know,its photocatalytic properties has never been reported . In this paper, single-phase Bi25FeO40 crystallites were prepared by using the PVA-assisted hydrothermal method, which is simple, energy saving and cost effective[12]. This technique possessed the potential to produce well-crystallized Bi25FeO40 powders with narrow distribution of particle size. The photocatalytic activity of Bi25FeO40 particles is also reported.
EXPERIMENT The sillenite catalysts were synthesized by PVA-assissted hydrothermal method. The chemical regents used in this work were bismuth nitrate [Bi(NO3)3·5H2O], iron nitrate [Fe(NO3)3·9H2O], hydro
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