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

A platinum nanowire network (approximate ∅4 nm) with silica nanoparticle (Ptnet/SiO2) spacers was prepared via spray drying and hydrogen reduction. The large network had few grain boundaries of crystalline platinum and enclosed SiO2 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 m2 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 VRHE) 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, Ptnet/SiO2 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 Ptnet/SiO2 was less than half that from Pt/C.

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► We develop a Pt nanowire network/SiO2 nanoparticles (Ptnet/SiO2) catalyst.
► The catalyst is produced by spray drying and hydrogen reduction.
► We demonstrate high oxygen reduction activity and durability of Ptnet/SiO2.
► A low selectivity of H2O2 generation on Ptnet contributes to the high activity.