Decomposição catalítica de peróxido de hidrogênio sobre os catalisadores de ZnO, CuO, Nb2O5, TiO2, CuO-Nb2O5 e CuO-TiO2.

Abstract

The importance of scientific knowledge of catalysts in chemical engineering can be evidenced by an observation that 80% of industrial products require the use of catalytic processes. One of the main objectives of the present work was To study the catalytic decomposition of hydrogen peroxide on ZnO, CuO, Nb2O5, Ti02 and CuO-Nb205 and CuO-Ti02. In the case of copper oxide supported on Nb2 ° 5 and Ti02, it was intended to study the synergistic effect of catalytic activity of mixed oxides with CuO composition variation. The catalytic activities of all the above metal oxides are determined using hydrogen peroxide decomposition as an oxidation-reduction reaction model. The ZnO, Nb205 and Ti02 samples used were "commercial" pure oxides. CuO was obtained from copper nitrate, Cu (NO3) 2 3H20. They were prepared by the impregnation method from the copper nitrate solution on Nb2O5 and Ti02 respectively. Five samples of CuO-Nb205 catalysts in the 3:97, 14:86, 40:60, 72,28 and 82:18 mass compositions, and five CuO-Ti02 catalysts in the 10:90, 37:63 mass compositions, 67:33, 73:27 and 93:07 respectively. All samples were calcined at 500 ° C for 6hs. The decomposition activity of H202 was determined. in terms of the volume of oxygen generated in a constant temperature batch reactor and total mixture. A peak in the catalytic activity curves of the samples was observed as the percentage of CUO over Nb20 or Ti02 increased. The initial decomposition speed increases in the following order for the compositions: 100: 0, 0: 100, 82:18, 72:28, 3:97, 40:60 and 14:86 for CuO-Nb205, and 10:90 , 37:63, 73:27, 67:33 and 93:07 for CuO-Ti02 at 40 ° C. Apparent activation energies of the ZnO, CuO, Nb205, Ti02, CuO-Nb205 (14:86) and CuO-Ti02 (93:07) samples were calculated at 16.4, 33.3,31.2, 30.0, 18.0 and 17.5 Kcal / mol respectively.