Platinum nanowire network with silica nanoparticle spacers for use as an oxygen reduction catalyst

Abstract A platinum nanowire network (approximate ∅4 nm) with silica nanoparticle (Pt net /SiO 2 ) spacers was prepared via spray drying and hydrogen reduction. The large network had few grain boundaries of crystalline platinum and enclosed SiO 2 nanoparticles (average ∅ 75 nm). These properties contributed to thermal and chemical stability of the structure. The nanowire network had a high electrochemical surface area (31.3 m 2  g -Pt −1 ), and acted as a catalyst for the oxygen reduction reaction. Its initial mass activity (110.5A g -Pt −1 at 0.85 V RHE ) was high compared to commercial Pt/C catalyst. Because of the chemical stability of the silica and the minimal amount of low-coordinated platinum in the platinum nanowires, Pt net /SiO 2 retained 77% of its initial activity after 27 000 redox cycles compared to 57% for commercial Pt/C. We also demonstrate that the hydrogen peroxide generation from Pt net /SiO 2 was less than half that from Pt/C.