02189nas a2200205   4500008004100000022001400041245016800055210006900223260007300292300001400365490000600379520132800385653002601713653002601739653002301765653002101788100002201809700002601831856012601857       2007                        eng d  a1566-736700aDirect formation of H2O2 from H-2 and O-2 and decomposition/hydrogenation of H2O2 in aqueous acidic reaction medium over halide-containing Pd/SiO2 catalytic system0 aDirect formation of H2O2 from H2 and O2 and decompositionhydroge  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC  a2222-22280 v83 a<p>Formation of H2O2 from H-2 and O-2 and decomposition/hydrogenation of H2O2 have been studied in aqueous acidic medium over Pd/SiO2 catalyst in presence of different halide ions (viz. F-, Cl- and Br-). The halide ions were introduced in the catalytic system via incorporating them in the catalyst or by adding into the reaction medium. The nature of the halide ions present in the catalytic system showed profound influence on the H2O2 formation selectivity in the H-2 to H2O2 oxidation over the catalyst. The H2O2 destruction via catalytic decomposition and by hydrogenation (in presence of hydrogen) was also found to be strongly dependent upon the nature of the halide ions present in the catalytic system. Among the different halides, Br- was found to selectivity promote the conversion of H-2 to H2O2 by significantly reducing the H2O2 decomposition and hydrogenation over the catalyst. The other halides, on the other hand, showed a negative influence on the H2O2 formation by promoting the H-2 combustion to water and/or by increasing the rate of decomposition/hydrogenation of H2O2 over the catalyst. An optimum concentration of Br- ions in the reaction medium or in the catalyst was found to be crucial for obtaining the higher H2O2, yield in the direct synthesis. (c) 2007 Elsevier B.V. All rights reserved.</p>10aBr- catalyst promoter10adirect H2O2 formation10aH2O2 decomposition10aPd/SiO2 catalyst1 aSamanta, Chanchal1 aChoudhary, Vasant, R.  uhttps://library.ncl.res.in/content/direct-formation-h2o2-h-2-and-o-2-and-decompositionhydrogenation-h2o2-aqueous-acidic-0