Direct synthesis of H2O2 on monometallic and bimetallic catalytic membranes using methanol as reaction medium

Tubular catalytic membranes (TMCs) active in the direct synthesis of hydrogen peroxide were prepared, characterized, and tested using methanol as the reaction medium. Low hydrogen peroxide selectivity was found When Only palladium was used as a catalyst, whereas palladium/platinum bimetallic samples gave higher productivity and selectivity, with an optimum molar ratio of 18. The H2O2 decomposition rate is influenced by the feed gases. O-2 improves H2O2 stability, whereas H-2 causes hydrogen peroxide to decompose at it higher rate. The most likely decomposition pathway should be the reduction of H2O2 to water by H-2. Bromide ion was used as a promoter and when used in excess (60 ppm) causes a decrease in overall catalytic activity. (c) 2005 Elsevier Inc. All rights reserved.