Photo-Fenton catalytic and photocatalytic performance of FeWO4 nanorods prepared at different pH

Abstract

Different sizes of FeWO4 nanorods were prepared employing a hydrothermal approach, solely by altering the pH of the precursor solution. The FeWO4 nanorods prepared at pH = 7 (FeWO4-7) were shorter than those prepared at pH = 2 (FeWO4-2). Compared with FeWO4-2, FeWO4-7 had bigger specific surface area, stronger visible-light-absorbing ability (smaller bandgap), and higher photogenerated charge separation and transfer efficiencies. Accordingly, FeWO4-7 exhibited much superior activity than FeWO4-2 in both photo-Fenton catalytic degradation of methylene blue (MB) and photocatalytic reduction of Cr(VI) under visible-light (λ > 420 nm) irradiation. The photo-Fenton catalytic and photocatalytic efficiencies of FeWO4-7 were about 8.5 and 2.9 times those of FeWO4-2, respectively. Furthermore, FeWO4-7 was reusable and fairly stable in both the photo-Fenton catalytic and photocatalytic applications. This study would be useful for guiding the hydrothermal preparation of high-efficiency visible-light-active FeWO4 photo-Fenton catalyst and photocatalyst, and the pH-modulated microstructural control method may be applicable to synthesize semiconductor nanomaterials with varied microstructures.