Enhanced Photo-Fenton Activity of SnO2/α-Fe2O3 Composites Prepared by a Two-Step Solvothermal Method

Abstract

The x-SnO2/α-Fe2O3 (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 SnO2 nanoparticles were uniformly decorated on the surface of α-Fe2O3 particles in these heterogeneous composites. A comparative study of methylene blue (MB) photodegradation by α-Fe2O3 and x-SnO2/α-Fe2O3 composites was carried out. All x-SnO2/α-Fe2O3 composites showed higher MB photodegradation efficiency than α-Fe2O3. 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-SnO2/α-Fe2O3 composite was 0.0537 min−1, while that of pure α-Fe2O3 was only 0.0191 min−1. The catalytic mechanism of MB photodegradation by SnO2/α-Fe2O3 was examined. The SnO2 can act as a sink and help the effective transfer of photo-generated electrons for decomposing hydrogen peroxide (H2O2) into active radicals. This work can provide a new insight into the catalytic mechanism of the photo-Fenton process.

The Photocatalytic Oxidation Ability of Rb0.9Nb1.625Mo0.375O5.62 with Classic β‐Pyrochlore Structure

“…Thus, the cubic crystal structure of the β-pyrochlore compound formed in the system Rb 2 OÀ Nb 2 O 5 À 2MoO 3 by specific synthesis method has been investigated. The possibility of the formation for only one composition with Nb : Mo = 13 : 3 using this method 0.0007 Visible light [23] RbTe 1.5 W 0.5 O 6 0.0004 Visible light [4d] TiO 2 (P25) 0.0106 UV light [32] SnO 2 0.0233 Visible light [33] α-Fe 2 O 3 0.0191 Visible light [33] has been emphasized. The range of differences between the compounds with same Nb : Mo ratio in octahedral framework and different symmetry prepared by solid state synthesis using stoichiometric reagents mixture and modified solid state synthesis has been obtained:…”