02700nas a2200241   4500008004100000022001400041245009100055210006900146260007300215300001200288490000800300520186300308653000902171653002302180653001902203653001202222653001702234653001702251100002602268700001602294700002602310856012202336       2006                        eng d  a1381-116900aFactors influencing decomposition of H2O2 over supported Pd catalyst in aqueous medium0 aFactors influencing decomposition of H2O2 over supported Pd cata  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC  a115-1200 v2603 a<p>Since H2O2 decomposition can result in selectivity/yield loss in the direct H2O2 synthesis process from H-2 and O-2 over supported Pd catalysts, it is important to have an enhanced understanding about the factors affecting the H2O2 decomposition reaction. Herein, detailed studies have been undertaken to investigate the influence of different factors, such as (a) nature and concentration of acid in reaction medium, (b) nature and concentration of halide in presence and absence of acid in reaction medium, (c) pretreatment procedures and (d) catalyst modification by incorporation of different halides, on the H2O2 decomposition reaction over a 5% Pd/C catalyst in aqueous medium at 25 degrees C. This study has shown that the H2O2 decomposition activity is profoundly influenced by all the above factors. The effectiveness of the acids in suppressing the H2O2 decomposition activity decreased in the following order: hydroiodic acid &gt; hydrobromic acid &gt; hydrochloric acid &gt;&gt; acetic acid &gt; phosphoric acid &gt; sulfuric acid &gt; perchloric acid. The ability of the acid to decrease the H2O2 decomposition activity was found to very strongly depend on the nature of its associated anion. Halides, such as iodide, bromide and chloride were particularly effective in suppressing the H2O2 decomposition activity. Oxidation pretreatment of the catalyst was found to strongly suppress its H2O2 decomposition activity, while a reduction treatment was found to promote its activity. A gradual decrease in the H2O2 decomposition activity of the catalyst was observed with each successive usage due to in situ sub-surface oxidation of Pd by H2O2. Halide incorporation either via the reaction medium or prior catalyst modification had a similar qualitative effect on the H2O2 decomposition activity. (c) 2006 Elsevier B.V. All rights reserved.</p>10aacid10aH2O2 decomposition10aH2O2 synthesis10ahalides10aPd catalysts10apretreatment1 aChoudhary, Vasant, R.1 aSamanta, C.1 aChoudhary, Tushar, V.  uhttps://library.ncl.res.in/content/factors-influencing-decomposition-h2o2-over-supported-pd-catalyst-aqueous-medium-0