Kinetics and Mechanism of Decomposition of Hydrogen Peroxide over Pd/SiO₂ Catalyst

Abstract

Kinetics of hydrogen peroxide decomposition over Pd/SiO 2 catalyst was investigated as part of a larger project to determine the overall kinetics of hydrogen peroxide formation by Pd/SiO 2 catalyzed direct combination of hydrogen and oxygen. A Pd oxidative/reductive cycle mechanism for the decomposition of H 2 O 2 over Pd/ SiO 2 was proposed. A Rideal-Eley rate expression based on this mechanism was shown to accurately correlate experimental data over a wide range of H 2 O 2 concentration and temperature. This rate equation was shown to also apply in the presence of stabilizing concentrations of H 2 SO 4 .

Direct synthesis of hydrogen peroxide using concentrated H2 and O2 mixtures in a wall-coated microchannel – kinetic study

“…This is a prerequisite for safe and long-term operation. Voloshin et al studied in detail the kinetics of direct synthesis of hydrogen peroxide over a Pd catalyst by isolating and separately studying direct synthesis [10] , hydrogenation [9] and decomposition [8] reaction in a packed-bed microchannel. Their work also indicated that the catalyst activity is highly influence by the reaction environment.…”

“…The effect of acid addition on the kinetics of the hydrogen peroxide decomposition over aPd catalyst was studied previously in detail by Voloshin et al [8] . We observed that at a sulfuric acid content of 0.05M and a NaBr content of approximately 10 ppm, the decomposition reaction is completely inhibited.…”

“…Micro-packed beds are nowadays commonly used in catalyst testing [7] or kinetic studies of heterogeneously catalyzed reactions [8][9][10] , since they simply allow application of already optimized or conventional catalysts available on the market. Typically, catalyst particles used are in a range of 50-150 µm [7,10] .…”

Electrochemical Characterization of Various Carbon-Supported Pt-Pd Bimetallic Electrocatalysts Prepared by Electroless Deposition

“…For both catalyst loadings, the amount of peroxide formed is significantly lower for the Pd-based catalyst than for the commercial Pt catalyst at potentials lower than 0.7 V vs. SHE. Both Pt and Pd not only produce H 2 O 2 during oxygen reduction (23,28), but are also active catalysts for hydrogen peroxide decomposition (29)(30)(31)(32). Vetter et al measured decomposition rates with Pt catalysts at various temperatures and determined the first order decomposition rate constant at 20-30 °C in pH 7 solution to be 3.6 x 10 -4 s -1 (29).…”

Catalytic activity of Schiff-base transition metal complexes supported on crosslinked polyacrylamides for hydrogen peroxide decomposition

“…In addition, Co (II)-monoethanolamine complex immobilized on Dowex-50W resin [39] has been effectively used for the decomposition. Moreover, functional inorganic supports have also been used for immobilization M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 3 of transition metal catalysts such as silica [40], propylpiperazine-silica matrix [41] and silicasand-goethite slurries [42] applied for this aim.…”