Effect of Halide and Acid Additives on the Direct Synthesis of Hydrogen Peroxide using Supported Gold–Palladium Catalysts

Abstract

Acidity is crucial: The effect of halide and acid addition on the direct synthesis of hydrogen peroxide is studied for magnesium oxide‐ and carbon‐supported bimetallic gold–palladium catalysts. When using a Au–Pd/C catalyst, the acidity of the methanol/water solvent has a profound effect on the productivity (P). The effect of halide and acid addition on the direct synthesis of hydrogen peroxide is studied for magnesium oxide‐ and carbon‐supported bimetallic gold–palladium catalysts. The addition of acids decreases the hydrogenation/decomposition of hydrogen peroxide, and the effect is particularly pronounced for the magnesium oxide‐supported catalysts whilst for carbon‐supported catalysts the pH requires close control to optimize hydrogen peroxide synthesis. The addition of bromide leads to a marked decrease in the hydrogenation/decomposition of hydrogen peroxide with either catalyst. These effects are discussed in terms of the structure of the gold–palladium alloy nanoparticles and the isoelectric point of the support. We conclude that with the highly active carbon‐supported gold–palladium catalysts these additives are not required and that therefore this system presents the potential for the direct synthesis of hydrogen peroxide to be operated using green process technology.