Catalytic wet oxidation of reactive dyes with H_2/O_2 mixture on Pd-Pt/Al_2O_3 catalysts

摘要

The Pd-Pt/Al_2O_3 bimetallic catalysts showed extremely high activities toward the wet oxidatio of the reactive dyes in the presence of % H_2 together with excess oxygen.Palladium acted as a promoter to spillover the adsorbed H_2 onto the surface of the oxidatized Pt surface,and thereby the reducibility of the Pt increased greatly.The organic dye molecular had hihger chance to adsorb on the reduced Pt surface under the competition with excess oxygen,thich is an essential step for the catalytic wet oxidation (CWO).The Pd-Pt/Al_2O_3 catalysts also produced H_2O_2 from H_2/O_2 mixture,and the hydroxyl radical was formed through the subsequent decomposition of H_2O_2.Additional oxidation of the reactive dyes was obtained with hydroxyl radical.The extremely hihg activities of the Pd-Pt/AL_2O_3 catalysts were believed to be due to the combined effects of the faster redox cycle resultig from the increased reducibility of Pt surface and the additional oxidation of the reactive dyes with hydroxyl radical.