Enhanced Photo-Fenton Activity of SnO(2)/α-Fe(2)O(3) Composites Prepared by a Two-Step Solvothermal Method

The x-SnO(2)/α-Fe(2)O(3) (x = 0.04, 0.07, and 0.1) heterogeneous composites were successfully prepared via a two-step solvothermal method. These composites were systematically characterized by the X-ray diffraction technique, field emission scanning electron microscopy, an energy dispersive spectrometer, X-ray photoelectron spectroscopy and a UV–visible spectrometer. It was found that SnO(2) nanoparticles were uniformly decorated on the surface of α-Fe(2)O(3) particles in these heterogeneous composites. A comparative study of methylene blue (MB) photodegradation by α-Fe(2)O(3) and x-SnO(2)/α-Fe(2)O(3) composites was carried out. All x-SnO(2)/α-Fe(2)O(3) composites showed higher MB photodegradation efficiency than α-Fe(2)O(3). When x = 0.07, the MB photodegradation efficiency can reach 97% in 60 min. Meanwhile, the first-order kinetic studies demonstrated that the optimal rate constant of 0.07-SnO(2)/α-Fe(2)O(3) composite was 0.0537 min(−1), while that of pure α-Fe(2)O(3) was only 0.0191 min(−1). The catalytic mechanism of MB photodegradation by SnO(2)/α-Fe(2)O(3) was examined. The SnO(2) can act as a sink and help the effective transfer of photo-generated electrons for decomposing hydrogen peroxide (H(2)O(2)) into active radicals. This work can provide a new insight into the catalytic mechanism of the photo-Fenton process.