Enhancing Fenton-like catalytic efficiency of Bi2WO6 by iodine doping for pollutant degradation

Abstract Introducing reductive species into heterogeneous catalysts can improve their catalytic efficiency in Fenton-like processes. Iodide ions (I−), a typical reductive species with good reducibility, might enhance the catalytic performance of H2O2 activation when doped in heterogeneous catalysts. In this study, the iodine-doped Bi2WO6 (IX-Bi2WO6) nanosheets were synthesized with a facile hydrothermal method and used to activate H2O2 to degrade bisphenol A (BPA). Compared with Bi2WO6, which was almost inactive, the IX-Bi2WO6 exhibited great improvement for BPA degradation. Among the fabricated catalysts, the I0.50-Bi2WO6 with an iodine content of 0.50 mmol was found to be most effective and could work efficiently in a wide pH range from 4.0 to 10.0. Moreover, with a low consumption of H2O2 (H2O2 : pollutant molar ratio = 10:1), 78% BPA was degraded within 10 min at initial pH 7.0. Unlike the conventional H2O2 activation mechanism, the direct electron transfer was verified to be the main mechanism for the BPA degradation based on the results of electron paramagnetic resonance (EPR) analysis, radical quenching, and electrochemical experiments in this work. Furthermore, the activation of H2O2 by iodine-doped BiVO4 and Bi2MoO6 was also conducted to validate the applicability of such an iodine doping approach. These results indicate that the introduction of reductive species I− is a promising and effective method to develop highly efficient Bi-based catalysts for H2O2 activation.