Solid-solution alloying of immiscible Pt and Au boosts catalytic performance for H2O2 direct synthesis

Abstract

Here, we propose the solid-solution alloy nanoparticles (NPs) composed of Pt and Au supported on TiO2 as an efficient catalyst for direct H2O2 synthesis, although Pt and Au are entirely immiscible in the bulk phases. Pt and Au atoms were homogeneously distributed in a wide composition range of Pt(x)Au(100-x)NPs (10 <= x <= 80) supported on TiO2. The most Au-rich Pt-10 Au-90 NPs/TiO2 exhibits the best catalytic performances, H2O2 selectivity (94.5 +/- 0.6%) and productivity (959 +/- 12 mmol(H2O2).g(metal)(-1).h(-1)), even under mild conditions (10 degrees C, 1 atm) and without halide-ion additives. Density functional theory calculations reveal that the introduction of inactive Au atoms strongly suppresses both O-O bond scission and OH hydrogenation, thereby enabling near unity selectivity. The Pt-Au catalyst is Pd-absent, which is noteworthy given previous efforts in direct H2O2 synthesis are mostly limited to prototypical Pd or Pd-based modifications. This work will stimulate active utilization of immiscible elemental combinations for the direct H2O2 synthesis catalyst development. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.