Materiais constituídos por Ni/Al-HDL modificados com paládio: testes catalíticos para oxidação de rodaminda b

Abstract

In this work LDH-based materials have been modified by incorporation of Pd and they have also been studied as catalytic support and/or catalysts themselves. The materials have been calcinated at different temperatures and atmospheres. They have been characterized by X ray diffraction (XRD), infrared spectroscopy (FT-IR), thermogravimetric analysis (TG), temperature-programmed reduction (TPR), diffuse reflectance spectroscopy (DRS), and BET surface area. Rhodamine B have been applied as a model pollutant for the photocatalytic tests. Intercalated water, hydroxyl and carbonate anions losses have been observed for all LDH-based materials at temperature about 500 o C. Pd-containing materials have presented lower band gap values and catalytic activity have increased to the composites which have been submitted to UVlight reduction or calcination process. Results indicate that the co-precipitation method led to the formation of the lamellar structure and that heat treatment above 500oC caused the structure to collapse generating mixed oxides. It was verified that the addition of Pd influenced the photocatalytic activity, the reduction capacity and the band gap energy value of the precursor material. The material submitted to the reduction showed higher photocatalytic activity than the others, which, in turn, did not present a high percentage of color removal during the photocatalytic reaction.