Generation of H2O2 from H2 and O2 over zeolite beta containing Pd and heterogenized organic compounds

The catalytic generation of H2O2 from H-2 and O-2 has been studied over zeolite beta-supported Pd and zeolite beta-adsorbed organic compounds such as 1,4-benzoquinone (BQ), hydroquinone (HQ), azobenzene (AB) and hydrazobenzene (HAB). According to catalytic results, zeolite beta-supported Pd catalysts display effective performance relative to those prepared from other types of zeolites reported and Pd-loaded zeolite beta-adsorbed HQ catalysts show enhanced activity compared to zeolite beta-supported Pd catalysts. In situ UV-Vis spectroscopic study indicates that HQ can readily be converted to BQ reversibly under H-2 and air inside zeolite beta only in the presence of Pd. The results suggest that HQ acts as a strong hydrogen transfer agent to promote the production of H2O2 from H-2 and O-2 in cooperation with a Pd catalyst. By contrast, adsorption of BQ, AB and HAB induces suppression of the catalytic properties of Pd/zeolite beta. (C) 2000 Elsevier Science B.V. All rights reserved.