A heterogeneous Fenton-like reaction occurring on the thermally modified surface of a synthetic iron oxide previously treated with a H-2 stream was investigated. The quinoline decomposition, used as an organic substrate model, was monitored with electrospray ionization mass spectrometry. Quinoline was found to be oxidized through a Successive hydroxylation mechanism. These results strongly suggest that highly reactive hydroxyl radicals, generated during the reaction involving H2O2 on the catalysts surface, respond for this oxidation, and confirm that the material is an efficient heterogeneous Fenton-like catalyst. Theoretical quantum mechanics calculations, by the density functional theory (DFT), were carried Out in Order to understand the basic molecular degradation steps for quinoline decomposition mechanism on this H-2-treated goethite (alpha FeOOH) surface. (c) 2008 Elsevier B.V. All rights reserved.