02262nas a2200253   4500008004100000022001400041245011900055210006900174260007300243300001200316490000800328520135700336653001801693653002101711653000901732653002001741653002001761653001701781653001301798100002601811700001601837700002601853856012901879       2006                        eng d  a0926-860X00aDirect oxidation of H-2 to H2O2 over Pd-based catalysts: influence of oxidation state, support and metal additives0 aDirect oxidation of H2 to H2O2 over Pdbased catalysts influence   aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUL  a128-1330 v3083 a<p>The influence of oxidation state (reduced and oxidized), support (ZrO2, Ga2O3, CeO2, SiO2, H-beta, ThO2, CeO2-ZrO2, BPO4 and Pd/Al2O3) and precious metal additives (Au, Pt, Rh and Ru) on the direct H2O2 synthesis has been investigated over Pd-based catalysts. For all the supports investigated herein, the oxidized Pd catalysts showed significantly superior H2O2 yields as compared to their reduced counterparts. The effect of the Pd oxidation state was found to be more important for determining the H2O2 yields than the particle size and surface area properties of the catalyst system. An excellent correlation was observed between the H2O2 selectivity and H2O2 decomposition activity of the oxidized Pd catalysts. The oxidized Pd catalysts showed almost an order of magnitude lower H2O2 decomposition activity than the reduced catalysts. The H2O2 yield in the H-2 to H2O2 oxidation passed through a maximum with increase in the An concentration. Although a similar effect was also observed in case of Pt, Au was found to be a superior promoter for the direct H2O2 synthesis process. Addition of Rh and Ru was found to be detrimental for the H2O2 yields; these results can be explained in terms of increased H2O2 decomposition activity and/or enhanced H-2 to H2O reaction activity in their presence. (c) 2006 Elsevier B.V. All rights reserved.</p>10adecomposition10adirect synthesis10aH2O210ametal additives10aoxidation state10aPd catalysts10asupports1 aChoudhary, Vasant, R.1 aSamanta, C.1 aChoudhary, Tushar, V.  uhttps://library.ncl.res.in/content/direct-oxidation-h-2-h2o2-over-pd-based-catalysts-influence-oxidation-state-support-and-0