Improving the performance of Pd based catalysts for the direct synthesis of hydrogen peroxide via acid incorporation during catalyst synthesis

The direct synthesis of hydrogen peroxide from molecular H2 and O2 offers an attractive alternative to the current means of production of this powerful oxidant, on an industrial scale. Herein we investigate the role of nitric acid addition, during catalyst preparation as a means of improving catalytic performance, under reaction conditions that have previously been found to be optimal for H2O2 production. The addition of dilute nitric acid during catalyst preparation is found to lead to a significant improvement in H2O2 synthesis activity, through the modification of particle size and control of Pd oxidation state

Effect of Reaction Conditions on the Direct Synthesis of Hydrogen Peroxide with a AuPd/TiO 2

The direct synthesis of hydrogen peroxide (H2O2) represents a potential alternative to the currently industrially used anthraquinone process, and Au–Pd catalysts have been identified as effective catalysts. To obtain a direct process, a detailed understanding of the reaction conditions in a continuous flow system is needed. In this study, we use a flow reactor to study reaction conditions independently, including total gas flow rate, catalyst mass, reaction pressure, solvent flow rate, and H2/O2 molar ratio. The study was carried out without the addition of any halide or acid additives often used to suppress the sequential hydrogenation and decomposition reactions that allowed the kinetics of these reactions to be studied along with the synthesis reaction. A global kinetic model describing the net and gross synthesis rate is proposed, and on the basis of this model, we propose that the decomposition reaction suppresses the production of H2O2 to a greater extent than hydrogenation and that catalyst design studies should aim at blocking or generating catalysts without O–O dissociation sites