Synthesis Dynamics of Silver Nanowires Galvanically Displaced by Platinum Salts
AdvisorBarile, Christopher J
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The advancement of conductive and flexible thin films is relevant to an assortment of energy applications ranging from organic photovoltaics, fuel cells, lithium ion batteries, and dynamic windows. Here, an inexpensive, fast, and adjustable method is proposed to yield nanowire arrays on flexible polyethylene terephthalate substrates for the alkaline oxygen reduction reaction and for reversible metal electrodeposition. Ag nanowires serve as a non-sacrificial template for Pt deposition and allow for the synthesis of bimetallic Pt/Ag nanowires. When not properly controlled, the galvanic displacement reaction occurring at the solid-liquid interface between Ag nanowires and aqueous Pt ions results in nonuniform nucleation and growth profiles, which creates micron-sized gaps in the nanowire arrays. These gaps, which result in poorly conducting thin films, increase in prevalence when immersion length and Pt concentration are increased. Multiple cycles of 10-minute immersions in 10 mM K2PtCl4 yield bimetallic Pt/Ag nanowires that maintain the high aspect ratios and conductivities of the initial Ag nanowires, while the added Pt improves electrocatalytic performance and electrochemical durability.