Direct synthesis of hydrogen peroxide in a wall coated microreactor using Au-Pd catalyst

Abstract onl

Development of uniform silica-based coatings for catalytic reactors

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Direct synthesis of hydrogen peroxide in a wall coated microreactor using Au-Pd catalyst

Abstract onl

Direct synthesis of hydrogen peroxide over Au-Pd catalyst : the effect of co-solvent addition

Direct synthesis represents a green alternative, an environmentally benign process for the production of hydrogen peroxide. This is a three-phase reaction, a solid catalyst with gas reactants and a liquid phase, which collects hydrogen peroxide formed from the catalyst surface. The choice of solvent and/or addition of promoters has a significant effect on the reaction rates observed, as well as selectivity towards peroxide. In addition to non-toxic water, short chain alcohols are very attractive, due to good solubility of reacting gases. Here we report an extensive study on the influence of different groups of solvents on the direct synthesis reaction when either applied alone or as co-solvent under non-explosive and conventionally explosive reaction conditions

Catalyst coating on prefabricated capillary microchannels for the direct synthesis of hydrogen peroxide

The geometric surface area of capillary microchannels is insufficient for the direct deposition of a catalyst active phase to reach a sufficient level of microreactor activity. For this reason it is necessary to coat a porous layer of a catalyst support on the channel wall prior to the deposition of the active metallic species. This work addresses the challenges related to the preparation of well-adhered and uniform silica coatings inside closed capillary channels suitable for catalyst deposition for the direct synthesis of hydrogen peroxide. The method used to deposit a layer of coating suspension, which upon solvent evaporation and heating is transformed into a solid film, is known as dynamic gas displacement. Variation of coating parameters and properties of the coating solution could be used to produce microreactors coated with different silica loadings. The most critical aspect of coating is maintaining the film regularity during and after displacement of the coating fluid. The uniformity of the coating thickness is greatly affected not only by the ability to maintain the coating parameters constant, such as the coating velocity, temperature, and solvent evaporation rate during and after displacement of the coating solution, but also by the rheological properties of the coating fluid. Advantages and disadvantages of different coating techniques such as colloidal coating, sol-gel, and slurry coating are discussed in detail. Finally, we demonstrate that silica wall-coated layers with embedded Au-Pd colloidal alloy nanoparticles are active in catalyzing the direct synthesis of hydrogen peroxide

Application of a bifunctional Pd/ZSM-5 catalyst in chip-microreactors

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