Slow Synthesis Methodology‐Directed Immiscible Octahedral PdxRh1−x Dual‐Atom‐Site Catalysts for Superior Three‐Way Catalytic Activities over Rh

This study provided an effective strategy to construct dual‐atom sites by solid–solution alloying. A slow synthesis methodology was established for the solid–solution preparations as dual‐atom‐site catalysts. The atomic‐level homogeneous PdxRh1−x dual‐atom‐site catalysts were successfully synthesized over the whole composition range, as evidenced by X‐ray powder diffraction and scanning transmission electron microscope energy‐dispersive X‐ray spectroscopy mapping measurements. The challenging morphology formation in the immiscible alloys was achieved by an energy‐controlling process as the octahedral Rh‐rich alloys. The Pd0.3Rh0.7 dual‐atom‐site catalyst had unique surface states to activate the key reactants of CO and NO in the complex three‐way catalytic reactions, and it performed significantly better than pure Rh. A novel synthetic methodology was established by diminishing the differences in reduction rates for the precursor systems to prepare homogeneous RhxPd1−x solid solutions as a dual‐atom‐site catalyst. The Rh−Pd dual‐atom sites in Pd0.1Rh0.9 and Pd0.3Rh0.7 could activate CO and NO in three‐way catalytic reactions, and showed superior activities over pure Rh.