Direct synthesis of hydrogen peroxide using Au–Pd-exchanged and supported heteropolyacid catalysts at ambient temperature using water as solvent

Abstract

The direct synthesis of hydrogen peroxide from molecular H₂ and O₂ represents a green and economic alternative to the current anthraquinone process used for the industrial production of H₂O₂. In order for the direct process to compete with the anthraquinone process, there is a need for enhanced H₂O₂ yields and H₂ selectivity in the process. We show that Au–Pd-exchanged and supported Cs-containing heteropolyacid catalysts with the Keggin structure are considerably more effective in achieving high H₂O₂ yields in the absence of acid or halide additives than previously reported catalysts. The Au–Pd-exchanged Cs-heteropolyacid catalysts also show superior H₂O₂ synthesis activity under challenging conditions (ambient temperature, water-only solvent and CO₂-free reaction gas). Au plays a crucial role in achieving the improved performance of these heteropolyacid-based catalysts. The heteropolyacid limits the subsequential hydrogenation/decomposition of H₂O₂.