Switching Off Hydrogen Peroxide Hydrogenation in the Direct Synthesis Process

Hydrogen peroxide (H 2 O 2 ) is an important disinfectant and bleach and is currently manufactured from an indirect process involving sequential hydrogenation/oxidation of anthaquinones. However, a direct process in which H 2 and O 2 are reacted would be preferable. Unfortunately, catalysts for the direct synthesis of H 2 O 2 are also effective for its subsequent decomposition, and this has limited their development. We show that acid pretreatment of a carbon support for gold-palladium alloy catalysts switches off the decomposition of H 2 O 2 . This treatment decreases the size of the alloy nanoparticles, and these smaller nanoparticles presumably decorate and inhibit the sites for the decomposition reaction. Hence, when used in the direct synthesis of H 2 O 2 , the acid-pretreated catalysts give high yields of H 2 O 2 with hydrogen selectivities greater than 95%.