Switching Off Hydrogen Peroxide Hydrogenation in the Direct Synthesis Process

TLDR

Hydrogen peroxide is a key disinfectant and bleach, currently produced via an indirect anthraquinone process, but catalysts for a direct synthesis are limited because they also promote H2O2 decomposition. The study aims to develop a direct synthesis of H2O2 by reacting H2 and O2. Acid pretreatment of the carbon support reduces gold‑palladium nanoparticle size, which is thought to block decomposition sites. The acid‑pretreated catalysts eliminate H2O2 decomposition and achieve high yields with >95 % hydrogen selectivity in the direct synthesis.

Abstract

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%.