Solid Acid Additives as Recoverable Promoters for the Direct Synthesis of Hydrogen Peroxide

The effectiveness of Cs-exchanged phosphotungstic acid as a recoverable solid acid additive for the direct synthesis of hydrogen peroxide (H 2 O 2 ) using an Au–Pd/TiO 2 catalyst is investigated and compared to the promotion effect of common oxides and nonhalo acids. A clear improvement in catalytic activity toward H 2 O 2 synthesis is reported when utilizing Cs-containing heteropolyacids in addition to a standard H 2 O 2 synthesizing catalyst. The effect of Cs content on the promotion of H 2 O 2 formation is investigated, and the feasibility of a reusable heterogeneous additive has been explored revealing that the presence of the acid additive not only stabilizes the H 2 O 2 that is produced but also increases the H 2 O 2 synthesis rate.