α-Ga2O3 is a wide-bandgap semiconductor material which was prepared by a novel synthesis method from metallic gallium. It was characterized by X-ray diffraction, infrared spectroscopy, ultraviolet spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy. This oxide was also evaluated as a photocatalyst toward the decomposition of malachite green (MG). X-ray photoelectron spectroscopy was used with the purpose of analyzing the changes on the surface of the material before and after the photocatalytic reaction. The results found by X-ray diffraction shows that alfa phase did not transform to another crystalline phase during the reaction. However, a slight change on the relative intensities of the planes (104) and (110), may explain the variation of the morphology of the oxide, associated to a preferential particle erosion. High resolution XPS analyses revealed a shift toward lower binding energies of the O1s level after the photocatalytic reaction, suggesting the presence of oxygen bound to carbonyls or alcohols. Organic nitrogenous residues associated to MG were also detected by the presence of the N1s band observed at 396.7 eV.