Synthesis of iron-doped Bi_2WO_6 high-performance visible-light-induced photo catalyst by a single-step solvo thermal process

摘要

In this study, iron-doped Bi2WO6 (FeBWs) photo catalyst was synthesized by a single-step solvo thermal process. Fe/W molar ratios of 0.1-10 were used. The surface characteristics of the prepared FeBWs were analyzed by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, transmission electron microscopy, specific surface area analysis, UV-Vis spectrophotometry, fluorescence spectrophotometry and X-ray photo electron spectroscopy. The photo catalytic activities of FeBWs were compared using the decolorization of C.I. Reactive Red 2 (RR2) with solar-light photo catalysis and visible-light photo catalysis. No XRD peaks of iron metal or iron oxide were detected, possibly because iron ions were doped into the lattice of Bi2WO6. The results of FTIR revealed that some iron ions substituted Bi3+ in FeBWs. Iron doping into Bi2WO6 reduced the band gap from 3.1 to 1.3 eV. All prepared FeBWs were visible-light-induced photo catalysts. The optimal Fe/W molar ratio was 5 and solar-light photo catalysis increased the RR2 decolorization rate from 3.34 h(-1) (Bi2WO6) to 8.48 h(-1) (FeBWs) while visible-light photo catalysis increased it from 0.11 h(-1) to 7.36 h(-1). The doping of iron ions into Bi2WO6 increased the separation of photo generated electron-hole pairs by acting as traps and increased photo catalytic performance. The photo generated holes and super oxide radicals were the major active species in FeBW photo catalysts.