Solid-Solution Alloying of Immiscible Pt and AU Boosts Catalytic Performance for H 2 O 2 Direct Synthesis

In the field of bimetallic catalysis, combinations of immiscible elements have been very limited. Here, we propose the solid-solution alloy nanoparticles (NPs) composed of Pt and Au supported on TiO 2 as an efficient catalyst for direct H 2 O 2 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 TiO 2 . The most Au-rich Pt 10 Au 90 NPs/TiO 2 exhibits the best catalytic performances, H 2 O 2 selectivity (94.5±0.6%) and productivity (959±12 mmol H2O2 •g metal -1 •h -1 ), even under mild conditions (10 °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. This work will stimulate active utilization of the overlooked class of immiscible elemental combinations for catalyst development.