Bimetallic Pt-Ni Aerogels for Electrocatalysis of the Oxygen Reduction Reaction
With this motivation in mind, we have studied both the ORR activity and potential stability of PtxNi aerogels (with x=1,3) consisting of an interconnected nanoparticle network, as exemplified by the transmission electron micrograph of the Pt3Ni aerogel displayed in Fig. 1. Derivatives of this material were subsequently obtained by potential-induced and chemically-driven leaching of the non-noble metal, along with mild heat-treatment to induce surface reconstruction.[2,7] The resulting materials were electrochemically characterized using the thin-film RDE technique  to quantify the catalyst’s surface area and specific activity in 0.1 M HClO4electrolyte using a three electrode setup and a custom-made glass cell. Additionally, extended potential cycling was performed to probe the stability of the as-synthesized, acid-leached and heat-treated aerogels. Ultimately, the obtained results were compared to those gathered on monometallic Pt aerogel and commercial Pt/C catalysts.
In summary, this contribution will report on the ORR activity and stability of new bimetallic noble metal/non-noble metal aerogels based on platinum and nickel. These results will provide valuable insights for the synthesis of further aerogel compounds with various compositions.
Figure 1. Transmission electron micrographs of a Pt3Ni aerogel catalyst, showing the individually connected nanoparticles with an averaged diameter of ~ 5.0 nm at low and high magnification (inset).
Funding from the Swiss National Science Foundation for financial support (contract number 20001E_151122/1) and the Deutsche Forschungsgemeinschaft (contract number EY 16/18-1) is greatly acknowledged.
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