New Complex Salts as Precursors of Porous Pd–Ir–Rh Nanoalloys

New complex salts [Pd(NH 3 ) 4 ] 3 [Ir(NO 2 ) 6 ] 2 x [Rh(NO 2 ) 6 ] 2 – 2 x ( II – VI ) were prepared, which are solid solutions based on double complex salts [Pd(NH 3 ) 4 ] 3 [Ir(NO 2 ) 6 ] 2 ( I ) and [Pd(NH 3 ) 4 ] 3 [Ir(NO 2 ) 6 ] 2 . The obtained compounds were characterized by X-ray powder diffraction analysis, IR spectroscopy, and elemental analysis. The compounds crystallize in the cubic system (space group F43̅c ). The thermal behavior of compounds I – VI in various gas atmospheres was investigated. The final products of thermolysis of [Pd(NH 3 ) 4 ] 3 [Ir(NO 2 ) 6 ] 2 x [Rh(NO 2 ) 6 ] 2 – 2 x in reducing (H 2 ) and inert (He) atmospheres were trimetallic porous Pd–Ir–Rh nanoalloys. The final products of thermolysis in an oxidizing atmosphere were mixtures of metal oxide phases with an admixture of a metal phase. The structural and morphological properties of the formed nanoalloys were studied. The obtained solid solutions of double complex salts [Pd(NH 3 ) 4 ] 3 [Ir(NO 2 ) 6 ] 2 x [Rh(NO 2 ) 6 ] 2 – 2 x were used to synthesize alloy nanoparticles on the surface of a γ-Al 2 O 3 oxide support. The catalytic activity and stability of the produced catalyst samples were tested in a model reaction of CO oxidation under forced thermal aging conditions.