Iron terephthalate metal-organic framework: Revealing the effective activation of hydrogen peroxide for the degradation of organic dye under visible light irradiation

Metal-organic frameworks (MOFs), a new class of porous crystalline materials, have attracted great interest as a promising candidate for sustainable energy and environmental remediation. In this study, we demonstrate that an iron terephthalate metal-organic framework MIL-53(Fe) synthesized by a facile solvothermal reaction was capable of activating hydrogen peroxide (H2O2) to achieve high efficiency in photocatalytic process. It could completely decompose the 10 mg L-1 Rhodamine B (RhB) in the presence of a certain amount of H2O2 under visible light irradiation within 50 min. The catalytic activities were found to be strongly affected by the various operating parameters, such as solution pH, initial dye concentration, and H2O2 dosage. The activation effects of MIL-53(Fe) were investigated through the detection of hydroxyl radicals ((OH)-O-center dot) and transient photocurrent responses, which revealed that the H2O2 behaved in two ways during the catalytic process: (i) it could be catalytically decomposed by MIL(Fe)-53 to produce (OH)-O-center dot radicals through the Fenton-like reaction; (ii) it could capture the photogenerated electrons in the conduction band of excited MIL-53(Fe) to form (OH)-O-center dot radicals under visible light irradiation. The ability of such iron-based MOFs to activate H2O2 may enable rational design of advanced MOF-based catalysts for environmental remediation. (C) 2013 Elsevier B.V. All rights reserved.