Nanoparticle catalysts for the direct synthesis of hydrogen peroxide

Abstract

The direct synthesis of H2O2 from H2 and O2 is a promising atom-efficient alternative to the industrial anthraquinone auto-oxidation process. However, the realization of this reaction nowadays is mainly hampered by the development of sufficiently selective catalysts, since H2O2 is a reactive intermediate and Pd-based catalysts are often equally efficient for its subsequent degradation to H2O. Reasonable yields with high selectivity can be obtained with Pd-based catalysts in the presence of promoters such as halides and acids which have several drawbacks concerning, e.g. corrosion and purification. Moreover, doping of Pd with other metals (multi-metallic system) could replace the use of acid and halide promoters. Additionally, selective modifications of the supports could further enhance the selectivity and productivity of H2O2. Herein, we synthesize Pd and Pb doped Pd nanoparticles (NPs) via colloidal chemistry and immobilized them on different support materials to study their role in the direct synthesis reaction. Several complementary analytic tools were employed to pinpoint the structure and elemental composition of the NPs and catalysts and to link the structural and compositional information of the NPs with the catalytic performance.