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